Structural basis for recognition of acidic-cluster dileucine sequence by GGA1.
GGAs (Golgi-localizing, gamma-adaptin ear homology domain, ARF-interacting proteins) are critical for the transport of soluble proteins from the trans-Golgi network (TGN) to endosomes/lysosomes by means of interactions with TGN-sorting receptors, ADP-ribosylation factor (ARF), and clathrin. The amino-terminal VHS domains of GGAs form complexes with the cytoplasmic domains of sorting receptors by recognizing acidic-cluster dileucine (ACLL) sequences. Here we report the X-ray structure of the GGA1 VHS domain alone, and in complex with the carboxy-terminal peptide of cation-independent mannose 6-phosphate receptor containing an ACLL sequence. The VHS domain forms a super helix with eight alpha-helices, similar to the VHS domains of TOM1 and Hrs. Unidirectional movements of helices alpha6 and alpha8, and some of their side chains, create a set of electrostatic and hydrophobic interactions for correct recognition of the ACLL peptide. This recognition mechanism provides the basis for regulation of protein transport from the TGN to endosomes/lysosomes, which is shared by sortilin and low-density lipoprotein receptor-related protein.
Pubmed ID: 11859376 RIS Download
ADP-Ribosylation Factors | Adaptor Proteins, Vesicular Transport | Amino Acid Sequence | Binding Sites | Carrier Proteins | Cloning, Molecular | Crystallography, X-Ray | Escherichia coli | Hydrogen-Ion Concentration | Leucine | Membrane Glycoproteins | Models, Molecular | Molecular Sequence Data | Nerve Tissue Proteins | Protein Binding | Protein Conformation | Protein Structure, Tertiary | Protein Transport | Receptor, IGF Type 2 | Structure-Activity Relationship | Two-Hybrid System Techniques