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CHO-K1

RRID:CVCL_0214

Organism

Cricetulus griseus

Comments

Doubling time: ~24 hours (DSMZ). Omics: Deep RNAseq analysis. Omics: Genome sequenced. Omics: Metabolome analysis. Omics: miRNA expression profiling. Omics: Transcriptome analysis. DT Created: 04-04-12; Last updated: 05-07-19; Version: 27

Proper Citation

BCRC Cat# 60006, RRID:CVCL_0214

Category

Spontaneously immortalized cell line DT Created: 04-04-12; Last updated: 05-07-19; Version: 27

Sex

DT Created: 04-04-12; Last updated: 05-07-19; Version: 27

Synonyms

CHO K1, CHOK1, CHO cell clone K1, GM15452 DT Created: 04-04-12, Last updated: 05-07-19, Version: 27

Vendor

BCRC

Cat Num

60006

Cross References

BTO; BTO:0000457 CLO; CLO_0002427 CLO; CLO_0002462 CLO; CLO_0002463 CLO; CLO_0026669 CLO; CLO_0050409 CLO; CLO_0050420 CLO; CLO_0050423 MCCL; MCC:0000103 CLDB; cl730 CLDB; cl731 CLDB; cl732 CLDB; cl734 CLDB; cl735 CLDB; cl738 CLDB; cl739 CLDB; cl740 CLDB; cl741 CLDB; cl4897 AddexBio; P0017001/33 ATCC; CCL-61 ATCC; CRL-9618 BCRC; 60006 BCRJ; 0069 CCLV; CCLV-RIE 0134 CCLV; CCLV-RIE 0315 CCRID; 3111C0001CCC000004 CCRID; 3111C0002000000006 CCRID; 3131C0001000100007 CCRID; 3142C0001000000018 CCRID; 3142C0001000000406 CCRID; 3153C0001000000066 CCTCC; GDC0018 ChEMBL-Cells; CHEMBL3307512 ChEMBL-Targets; CHEMBL614031 CLS; 603480/p693_CHO-K1 Coriell; GM15452 DSMZ; ACC-110 ECACC; 85051005 GEO; GSM1968555 GEO; GSM1968563 GEO; GSM1968571 GEO; GSM1968572 GEO; GSM1968569 GEO; GSM1968570 GEO; GSM1968594 GEO; GSM1968596 GEO; GSM1968598 GEO; GSM1968589 GEO; GSM1968600 GEO; GSM1968599 GEO; GSM1968591 GEO; GSM1968593 GEO; GSM1968595 GEO; GSM1968597 GEO; GSM1968565 GEO; GSM1968566 GEO; GSM1968560 GEO; GSM1968559 GEO; GSM1968558 GEO; GSM1968561 GEO; GSM1968557 GEO; GSM1968562 GEO; GSM1968564 GEO; GSM1968567 GEO; GSM1968556 GEO; GSM1968568 IBRC; C10136 ICLC; ATL98003 IZSLER; BS CL 15 JCRB; IFO50414 JCRB; JCRB9018 KCB; KCB 88028YJ KCLB; 10061 Lonza; 44 MetaboLights; MTBLS493 NCBI_Iran; C645 RCB; RCB0285 RCB; RCB2330 RCB; RCB2869 TKG; TKG 0328 TOKU-E; 949 TOKU-E; 950 Wikidata; Q54812705 DT Created: 04-04-12; Last updated: 05-07-19; Version: 27

Hierarchy

DT Created: 04-04-12; Last updated: 05-07-19; Version: 27

Immunomimetic Designer Cells Protect Mice from MRSA Infection.

  • Liu Y
  • Cell
  • 2018 Jun 12

Literature context:


Abstract:

Many community- and hospital-acquired bacterial infections are caused by antibiotic-resistant pathogens. Methicillin-resistant Staphylococcus aureus (MRSA) predisposes humans to invasive infections that are difficult to eradicate. We designed a closed-loop gene network programming mammalian cells to autonomously detect and eliminate bacterial infections. The genetic circuit contains human Toll-like receptors as the bacterial sensor and a synthetic promoter driving reversible and adjustable expression of lysostaphin, a bacteriolytic enzyme highly lethal to S. aureus. Immunomimetic designer cells harboring this genetic circuit exhibited fast and robust sense-and-destroy kinetics against live staphylococci. When tested in a foreign-body infection model in mice, microencapsulated cell implants prevented planktonic MRSA infection and reduced MRSA biofilm formation by 91%. Notably, this system achieved a 100% cure rate of acute MRSA infections, whereas conventional vancomycin treatment failed. These results suggest that immunomimetic designer cells could offer a therapeutic approach for early detection, prevention, and cure of pathogenic infections in the post-antibiotic era.

Funding information:
  • Biotechnology and Biological Sciences Research Council - BB/J015652/1(United Kingdom)

Single-Molecule Microscopy Reveals Dynamic FLNA Interactions Governing SSTR2 Clustering and Internalization.

  • Treppiedi D
  • Endocrinology
  • 2018 Jun 19

Literature context:


Abstract:

The cytoskeletal protein filamin A (FLNA) has been suggested to play an important role in the responsiveness of GH-secreting pituitary tumors to somatostatin receptor subtype 2 (SSTR2) agonists, by regulating SSTR2 expression and signaling. However, the underlying mechanisms are unknown. Here, we use fast multi-color single-molecule microscopy to image individual SSTR2 and FLNA molecules at the surface of living cells with unprecedented spatiotemporal resolution. We find that SSTR2 and FLNA undergo transient interactions, which occur preferentially along actin fibers and contribute to restraining SSTR2 diffusion. Agonist stimulation increases the localization of SSTR2 along actin fibers and, subsequently, SSTR2 clustering and recruitment to clathrin-coated pits (CCPs). Interfering with FLNA-SSTR2 binding with a dominant-negative FLNA fragment increases SSTR2 mobility, hampers the formation and alignment of SSTR2 clusters along actin fibers, and impairs both SSTR2 recruitment to CCPs and SSTR2 internalization. These findings indicate that dynamic SSTR2-FLNA interactions critically control the nanoscale localization of SSTR2 at the plasma membrane and are required for coupling SST2R clustering to internalization. These mechanisms explain the critical role of FLNA in the control of SST2R expression and signaling and suggest the possibility of targeting SSTR2-FLNA interactions for the therapy of pharmacologically resistant GH-secreting pituitary tumors.

Funding information:
  • NIAID NIH HHS - AI063523-03(United States)

Unbiased Combinatorial Screening Identifies a Bispecific IgG1 that Potently Inhibits HER3 Signaling via HER2-Guided Ligand Blockade.

  • Geuijen CAW
  • Cancer Cell
  • 2018 May 14

Literature context:


Abstract:

HER2-driven cancers require phosphatidylinositide-3 kinase (PI3K)/Akt signaling through HER3 to promote tumor growth and survival. The therapeutic benefit of HER2-targeting agents, which depend on PI3K/Akt inhibition, can be overcome by hyperactivation of the heregulin (HRG)/HER3 pathway. Here we describe an unbiased phenotypic combinatorial screening approach to identify a bispecific immunoglobulin G1 (IgG1) antibody against HER2 and HER3. In tumor models resistant to HER2-targeting agents, the bispecific IgG1 potently inhibits the HRG/HER3 pathway and downstream PI3K/Akt signaling via a "dock & block" mechanism. This bispecific IgG1 is a potentially effective therapy for breast cancer and other tumors with hyperactivated HRG/HER3 signaling.

Funding information:
  • Wellcome Trust - (United Kingdom)

Dynamic Ligand Discrimination in the Notch Signaling Pathway.

  • Nandagopal N
  • Cell
  • 2018 Feb 8

Literature context:


Abstract:

The Notch signaling pathway comprises multiple ligands that are used in distinct biological contexts. In principle, different ligands could activate distinct target programs in signal-receiving cells, but it is unclear how such ligand discrimination could occur. Here, we show that cells use dynamics to discriminate signaling by the ligands Dll1 and Dll4 through the Notch1 receptor. Quantitative single-cell imaging revealed that Dll1 activates Notch1 in discrete, frequency-modulated pulses that specifically upregulate the Notch target gene Hes1. By contrast, Dll4 activates Notch1 in a sustained, amplitude-modulated manner that predominantly upregulates Hey1 and HeyL. Ectopic expression of Dll1 or Dll4 in chick neural crest produced opposite effects on myogenic differentiation, showing that ligand discrimination can occur in vivo. Finally, analysis of chimeric ligands suggests that ligand-receptor clustering underlies dynamic encoding of ligand identity. The ability of the pathway to utilize ligands as distinct communication channels has implications for diverse Notch-dependent processes.

Funding information:
  • NEI NIH HHS - EY012135(United States)

Ca2+ -dependent down-regulation of human histamine H1 receptors in Chinese hamster ovary cells.

  • Hishinuma S
  • J. Neurochem.
  • 2018 Jan 2

Literature context:


Abstract:

Gq/11 protein-coupled human histamine H1 receptors in Chinese hamster ovary cells stimulated with histamine undergo clathrin-dependent endocytosis followed by proteasome/lysosome-mediated down-regulation. In this study, we evaluated the effects of a sustained increase in intracellular Ca2+ concentrations induced by a receptor-bypassed stimulation with ionomycin, a Ca2+ ionophore, on the endocytosis and down-regulation of H1 receptors in Chinese hamster ovary cells. All cellular and cell-surface H1 receptors were detected by the binding of [3 H]mepyramine to intact cells sensitive to the hydrophobic and hydrophilic H1 receptor ligands, mepyramine and pirdonium, respectively. The pretreatment of cells with ionomycin markedly reduced the mepyramine- and pirdonium-sensitive binding sites of [3 H]mepyramine, which were completely abrogated by the deprivation of extracellular Ca2+ and partially by a ubiquitin-activating enzyme inhibitor (UBEI-41), but were not affected by inhibitors of calmodulin (W-7 or calmidazolium) and protein kinase C (chelerythrine or GF109203X). These ionomycin-induced changes were also not affected by inhibitors of receptor endocytosis via clathrin (hypertonic sucrose) and caveolae/lipid rafts (filipin or nystatin) or by inhibitors of lysosomes (E-64, leupeptin, chloroquine, or NH4 Cl), proteasomes (lactacystin or MG-132), and a Ca2+ -dependent non-lysosomal cysteine protease (calpain) (MDL28170). Since H1 receptors were normally detected by confocal immunofluorescence microscopy with an antibody against H1 receptors, even after the ionomycin treatment, H1 receptors appeared to exist in a form to which [3 H]mepyramine was unable to bind. These results suggest that H1 receptors are apparently down-regulated by a sustained increase in intracellular Ca2+ concentrations with no process of endocytosis and lysosomal/proteasomal degradation of receptors.

Funding information:
  • Medical Research Council - G117/563(United Kingdom)

Sculpting ion channel functional expression with engineered ubiquitin ligases.

  • Kanner SA
  • Elife
  • 2017 Dec 19

Literature context:


Abstract:

The functional repertoire of surface ion channels is sustained by dynamic processes of trafficking, sorting, and degradation. Dysregulation of these processes underlies diverse ion channelopathies including cardiac arrhythmias and cystic fibrosis. Ubiquitination powerfully regulates multiple steps in the channel lifecycle, yet basic mechanistic understanding is confounded by promiscuity among E3 ligase/substrate interactions and ubiquitin code complexity. Here we targeted the catalytic domain of E3 ligase, CHIP, to YFP-tagged KCNQ1 ± KCNE1 subunits with a GFP-nanobody to selectively manipulate this channel complex in heterologous cells and adult rat cardiomyocytes. Engineered CHIP enhanced KCNQ1 ubiquitination, eliminated KCNQ1 surface-density, and abolished reconstituted K+ currents without affecting protein expression. A chemo-genetic variation enabling chemical control of ubiquitination revealed KCNQ1 surface-density declined with a ~ 3.5 hr t1/2 by impaired forward trafficking. The results illustrate utility of engineered E3 ligases to elucidate mechanisms underlying ubiquitin regulation of membrane proteins, and to achieve effective post-translational functional knockdown of ion channels.

Funding information:
  • NCI NIH HHS - P30 CA013696()
  • NCRR NIH HHS - S10 RR027050()
  • NEI NIH HHS - (R01EY021716(United States)
  • NHLBI NIH HHS - R01 HL121253()
  • NHLBI NIH HHS - R01 HL122421()
  • NIGMS NIH HHS - T32 GM007367()

A J-Protein Co-chaperone Recruits BiP to Monomerize IRE1 and Repress the Unfolded Protein Response.

  • Amin-Wetzel N
  • Cell
  • 2017 Dec 14

Literature context:


Abstract:

When unfolded proteins accumulate in the endoplasmic reticulum (ER), the unfolded protein response (UPR) increases ER-protein-folding capacity to restore protein-folding homeostasis. Unfolded proteins activate UPR signaling across the ER membrane to the nucleus by promoting oligomerization of IRE1, a conserved transmembrane ER stress receptor. However, the coupling of ER stress to IRE1 oligomerization and activation has remained obscure. Here, we report that the ER luminal co-chaperone ERdj4/DNAJB9 is a selective IRE1 repressor that promotes a complex between the luminal Hsp70 BiP and the luminal stress-sensing domain of IRE1α (IRE1LD). In vitro, ERdj4 is required for complex formation between BiP and IRE1LD. ERdj4 associates with IRE1LD and recruits BiP through the stimulation of ATP hydrolysis, forcibly disrupting IRE1 dimers. Unfolded proteins compete for BiP and restore IRE1LD to its default, dimeric, and active state. These observations establish BiP and its J domain co-chaperones as key regulators of the UPR.

Funding information:
  • NIDDK NIH HHS - DK-64400(United States)

Bias Factor and Therapeutic Window Correlate to Predict Safer Opioid Analgesics.

  • Schmid CL
  • Cell
  • 2017 Nov 16

Literature context:


Abstract:

Biased agonism has been proposed as a means to separate desirable and adverse drug responses downstream of G protein-coupled receptor (GPCR) targets. Herein, we describe structural features of a series of mu-opioid-receptor (MOR)-selective agonists that preferentially activate receptors to couple to G proteins or to recruit βarrestin proteins. By comparing relative bias for MOR-mediated signaling in each pathway, we demonstrate a strong correlation between the respiratory suppression/antinociception therapeutic window in a series of compounds spanning a wide range of signaling bias. We find that βarrestin-biased compounds, such as fentanyl, are more likely to induce respiratory suppression at weak analgesic doses, while G protein signaling bias broadens the therapeutic window, allowing for antinociception in the absence of respiratory suppression.

Control of Cell Shape, Neurite Outgrowth, and Migration by a Nogo-A/HSPG Interaction.

  • Kempf A
  • Dev. Cell
  • 2017 Oct 9

Literature context:


Abstract:

Heparan sulfate proteoglycans (HSPGs) critically modulate adhesion-, growth-, and migration-related processes. Here, we show that the transmembrane protein, Nogo-A, inhibits neurite outgrowth and cell spreading in neurons and Nogo-A-responsive cell lines via HSPGs. The extracellular, active 180 amino acid Nogo-A region, named Nogo-A-Δ20, binds to heparin and brain-derived heparan sulfate glycosaminoglycans (GAGs) but not to the closely related chondroitin sulfate GAGs. HSPGs are required for Nogo-A-Δ20-induced inhibition of adhesion, cell spreading, and neurite outgrowth, as well as for RhoA activation. Surprisingly, we show that Nogo-A-Δ20 can act via HSPGs independently of its receptor, Sphingosine-1-Phosphate receptor 2 (S1PR2). We thereby identify the HSPG family members syndecan-3 and syndecan-4 as functional receptors for Nogo-A-Δ20. Finally, we show in explant cultures ex vivo that Nogo-A-Δ20 promotes the migration of neuroblasts via HSPGs but not S1PR2.

Heterophilic Type II Cadherins Are Required for High-Magnitude Synaptic Potentiation in the Hippocampus.

  • Basu R
  • Neuron
  • 2017 Sep 27

Literature context:


Abstract:

Hippocampal CA3 neurons form synapses with CA1 neurons in two layers, stratum oriens (SO) and stratum radiatum (SR). Each layer develops unique synaptic properties but molecular mechanisms that mediate these differences are unknown. Here, we show that SO synapses normally have significantly more mushroom spines and higher-magnitude long-term potentiation (LTP) than SR synapses. Further, we discovered that these differences require the Type II classic cadherins, cadherins-6, -9, and -10. Though cadherins typically function via trans-cellular homophilic interactions, our results suggest presynaptic cadherin-9 binds postsynaptic cadherins-6 and -10 to regulate mushroom spine density and high-magnitude LTP in the SO layer. Loss of these cadherins has no effect on the lower-magnitude LTP typically observed in the SR layer, demonstrating that cadherins-6, -9, and -10 are gatekeepers for high-magnitude LTP. Thus, Type II cadherins may uniquely contribute to the specificity and strength of synaptic changes associated with learning and memory.

Funding information:
  • NEI NIH HHS - R01 EY022073()

SUMOylation determines the voltage required to activate cardiac IKs channels.

  • Xiong D
  • Proc. Natl. Acad. Sci. U.S.A.
  • 2017 Aug 8

Literature context:


Abstract:

IKs channels open in response to depolarization of the membrane voltage during the cardiac action potential, passing potassium ions outward to repolarize ventricular myocytes and end each beat. Here, we show that the voltage required to activate IKs channels depends on their covalent modification by small ubiquitin-like modifier (SUMO) proteins. IKs channels are comprised of four KCNQ1 pore-forming subunits, two KCNE1 accessory subunits, and up to four SUMOs, one on Lys424 of each KCNQ1 subunit. Each SUMO shifts the half-maximal activation voltage (V1/2) of IKs ∼ +8 mV, producing a maximal +34-mV shift in neonatal mouse cardiac myocytes or Chinese hamster ovary (CHO) cells expressing the mouse or human subunits. Unexpectedly, channels formed without KCNE1 carry at most two SUMOs despite having four available KCNQ1-Lys424 sites. SUMOylation of KCNQ1 is KCNE1 dependent and determines the native attributes of cardiac IKs in vivo.

Expression, purification, and spectral tuning of RhoGC, a retinylidene/guanylyl cyclase fusion protein and optogenetics tool from the aquatic fungus Blastocladiella emersonii.

  • Trieu MM
  • J. Biol. Chem.
  • 2017 Jun 23

Literature context:


Abstract:

RhoGC is a rhodopsin (Rho)-guanylyl cyclase (GC) gene fusion molecule that is central to zoospore phototaxis in the aquatic fungus Blastocladiella emersonii It has generated considerable excitement because of its demonstrated potential as a tool for optogenetic manipulation of cell-signaling pathways involving cyclic nucleotides. However, a reliable method for expressing and purifying RhoGC is currently lacking. We present here an expression and purification system for isolation of the full-length RhoGC protein expressed in HEK293 cells in detergent solution. The protein exhibits robust light-dependent guanylyl cyclase activity, whereas a truncated form lacking the 17- to 20-kDa N-terminal domain is completely inactive under identical conditions. Moreover, we designed several RhoGC mutants to increase the utility of the protein for optogenetic studies. The first class we generated has altered absorption spectra designed for selective activation by different wavelengths of light. Two mutants were created with blue-shifted (E254D, λmax = 390 nm; D380N, λmax = 506 nm) and one with red-shifted (D380E, λmax = 533 nm) absorption maxima relative to the wild-type protein (λmax = 527 nm). We also engineered a double mutant, E497K/C566D, that changes the enzyme to a specific, light-stimulated adenylyl cyclase that catalyzes the formation of cAMP from ATP. We anticipate that this expression/purification system and these RhoGC mutants will facilitate mechanistic and structural exploration of this important enzyme.

Funding information:
  • NEI NIH HHS - R01 EY007965()
  • NIGMS NIH HHS - R01 GM034548()
  • NIGMS NIH HHS - R01 GM094468()
  • NIGMS NIH HHS - R01 GM096053()
  • NIGMS NIH HHS - T32 GM007596()

An Adenosine Receptor for Olfaction in Fish.

  • Wakisaka N
  • Curr. Biol.
  • 2017 May 22

Literature context:


Abstract:

Nucleotides released from food sources into environmental water are supposed to act as feeding cues for many fish species. However, it remains unknown how fish can sensitively detect those nucleotides. Here we discover a novel olfactory mechanism for ATP sensing in zebrafish. Upon entering into the nostril, ATP is efficiently converted into adenosine through enzymatic reactions of two ecto-nucleotidases expressed in the olfactory epithelium. Adenosine subsequently activates a small population of olfactory sensory neurons expressing a novel adenosine receptor A2c that is unique to fishes and amphibians. The information is then transmitted to a single glomerulus in the olfactory bulb and further to four regions in higher olfactory centers. These results provide conclusive evidence for a sophisticated enzyme-linked receptor mechanism underlying detection of ATP as a food-derived attractive odorant linking to foraging behavior that is crucial and common to aquatic lower vertebrates.

Co-option of an endogenous retrovirus envelope for host defense in hominid ancestors.

  • Blanco-Melo D
  • Elife
  • 2017 Apr 11

Literature context:


Abstract:

Endogenous retroviral sequences provide a molecular fossil record of ancient infections whose analysis might illuminate mechanisms of viral extinction. A close relative of gammaretroviruses, HERV-T, circulated in primates for ~25 million years (MY) before apparent extinction within the past ~8 MY. Construction of a near-complete catalog of HERV-T fossils in primate genomes allowed us to estimate a ~32 MY old ancestral sequence and reconstruct a functional envelope protein (ancHTenv) that could support infection of a pseudotyped modern gammaretrovirus. Using ancHTenv, we identify monocarboxylate transporter-1 (MCT-1) as a receptor used by HERV-T for attachment and infection. A single HERV-T provirus in hominid genomes includes an env gene (hsaHTenv) that has been uniquely preserved. This apparently exapted HERV-T env could not support virion infection but could block ancHTenv mediated infection, by causing MCT-1 depletion from cell surfaces. Thus, hsaHTenv may have contributed to HERV-T extinction, and could also potentially regulate cellular metabolism.

Cell-Cell Contact Area Affects Notch Signaling and Notch-Dependent Patterning.

  • Shaya O
  • Dev. Cell
  • 2017 Mar 13

Literature context:


Abstract:

During development, cells undergo dramatic changes in their morphology. By affecting contact geometry, these morphological changes could influence cellular communication. However, it has remained unclear whether and how signaling depends on contact geometry. This question is particularly relevant for Notch signaling, which coordinates neighboring cell fates through direct cell-cell signaling. Using micropatterning with a receptor trans-endocytosis assay, we show that signaling between pairs of cells correlates with their contact area. This relationship extends across contact diameters ranging from micrometers to tens of micrometers. Mathematical modeling predicts that dependence of signaling on contact area can bias cellular differentiation in Notch-mediated lateral inhibition processes, such that smaller cells are more likely to differentiate into signal-producing cells. Consistent with this prediction, analysis of developing chick inner ear revealed that ligand-producing hair cell precursors have smaller apical footprints than non-hair cells. Together, these results highlight the influence of cell morphology on fate determination processes.

KCTD Hetero-oligomers Confer Unique Kinetic Properties on Hippocampal GABAB Receptor-Induced K+ Currents.

  • Fritzius T
  • J. Neurosci.
  • 2017 Feb 1

Literature context:


Abstract:

GABAB receptors are the G-protein coupled receptors for the main inhibitory neurotransmitter in the brain, GABA. GABAB receptors were shown to associate with homo-oligomers of auxiliary KCTD8, KCTD12, KCTD12b, and KCTD16 subunits (named after their T1 K+-channel tetramerization domain) that regulate G-protein signaling of the receptor. Here we provide evidence that GABAB receptors also associate with hetero-oligomers of KCTD subunits. Coimmunoprecipitation experiments indicate that two-thirds of the KCTD16 proteins in the hippocampus of adult mice associate with KCTD12. We show that the KCTD proteins hetero-oligomerize through self-interacting T1 and H1 homology domains. Bioluminescence resonance energy transfer measurements in live cells reveal that KCTD12/KCTD16 hetero-oligomers associate with both the receptor and the G-protein. Electrophysiological experiments demonstrate that KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties on G-protein-activated Kir3 currents. During prolonged receptor activation (one min) KCTD12/KCTD16 hetero-oligomers produce moderately desensitizing fast deactivating K+ currents, whereas KCTD12 and KCTD16 homo-oligomers produce strongly desensitizing fast deactivating currents and nondesensitizing slowly deactivating currents, respectively. During short activation (2 s) KCTD12/KCTD16 hetero-oligomers produce nondesensitizing slowly deactivating currents. Electrophysiological recordings from hippocampal neurons of KCTD knock-out mice are consistent with these findings and indicate that KCTD12/KCTD16 hetero-oligomers increase the duration of slow IPSCs. In summary, our data demonstrate that simultaneous assembly of distinct KCTDs at the receptor increases the molecular and functional repertoire of native GABAB receptors and modulates physiologically induced K+ current responses in the hippocampus. SIGNIFICANCE STATEMENT: The KCTD proteins 8, 12, and 16 are auxiliary subunits of GABAB receptors that differentially regulate G-protein signaling of the receptor. The KCTD proteins are generally assumed to function as homo-oligomers. Here we show that the KCTD proteins also assemble hetero-oligomers in all possible dual combinations. Experiments in live cells demonstrate that KCTD hetero-oligomers form at least tetramers and that these tetramers directly interact with the receptor and the G-protein. KCTD12/KCTD16 hetero-oligomers impart unique kinetic properties to GABAB receptor-induced Kir3 currents in heterologous cells. KCTD12/KCTD16 hetero-oligomers are abundant in the hippocampus, where they prolong the duration of slow IPSCs in pyramidal cells. Our data therefore support that KCTD hetero-oligomers modulate physiologically induced K+ current responses in the brain.

Atomic structures of fibrillar segments of hIAPP suggest tightly mated β-sheets are important for cytotoxicity.

  • Krotee P
  • Elife
  • 2017 Jan 3

Literature context:


Abstract:

hIAPP fibrils are associated with Type-II Diabetes, but the link of hIAPP structure to islet cell death remains elusive. Here we observe that hIAPP fibrils are cytotoxic to cultured pancreatic β-cells, leading us to determine the structure and cytotoxicity of protein segments composing the amyloid spine of hIAPP. Using the cryoEM method MicroED, we discover that one segment, 19-29 S20G, forms pairs of β-sheets mated by a dry interface that share structural features with and are similarly cytotoxic to full-length hIAPP fibrils. In contrast, a second segment, 15-25 WT, forms non-toxic labile β-sheets. These segments possess different structures and cytotoxic effects, however, both can seed full-length hIAPP, and cause hIAPP to take on the cytotoxic and structural features of that segment. These results suggest that protein segment structures represent polymorphs of their parent protein and that segment 19-29 S20G may serve as a model for the toxic spine of hIAPP.

SUMOylation of NaV1.2 channels mediates the early response to acute hypoxia in central neurons.

  • Plant LD
  • Elife
  • 2016 Dec 28

Literature context:


Abstract:

The mechanism for the earliest response of central neurons to hypoxia-an increase in voltage-gated sodium current (INa)-has been unknown. Here, we show that hypoxia activates the Small Ubiquitin-like Modifier (SUMO) pathway in rat cerebellar granule neurons (CGN) and that SUMOylation of NaV1.2 channels increases INa. The time-course for SUMOylation of single NaV1.2 channels at the cell surface and changes in INa coincide, and both are prevented by mutation of NaV1.2-Lys38 or application of a deSUMOylating enzyme. Within 40 s, hypoxia-induced linkage of SUMO1 to the channels is complete, shifting the voltage-dependence of channel activation so that depolarizing steps evoke larger sodium currents. Given the recognized role of INa in hypoxic brain damage, the SUMO pathway and NaV1.2 are identified as potential targets for neuroprotective interventions.

Funding information:
  • NHLBI NIH HHS - R01 HL105949()
  • NIGMS NIH HHS - R01 GM111716()
  • NINDS NIH HHS - R01 NS056313()
  • NINDS NIH HHS - R01 NS058505()