The PACSINs are a family of cytoplasmic phosphoproteins that play a role in vesicle formation and transport. We report the cloning and cDNA sequencing of PACSIN 3 and the analysis of all three PACSIN isoforms with regard to tissue distribution, ligand binding properties and influence on endocytosis. PACSIN 3 differs from the other family members in having a short proline-rich region and lacking asparagine-proline-phenylalanine motifs. In contrast to the neurospecific PACSIN 1 and the ubiquitously expressed PACSIN 2, PACSIN 3 is mainly detected in lung and muscle tissues. All isoforms potentially oligomerize and bind to dynamin, synaptojanin 1 and N-WASP via their Src homology 3 domains. The PACSIN proteins colocalize with dynamin, but not with clathrin, implying a specific role with a distinct subpopulation of dynamin at defined cellular sites. Transferrin endocytosis is blocked in a dose-dependent manner in cells overexpressing the PACSIN variants, but the inhibitory effect can be abolished by mutating specific amino acid residues in the Src homology 3 domains. These characteristics of the PACSIN protein family suggest a general function in recruitment of the interacting proteins to sites of endocytosis.
Pubmed ID: 11082044 RIS Download
Mesh terms: Adaptor Proteins, Signal Transducing | Amino Acid Sequence | Animals | Base Sequence | DNA, Complementary | Dynamins | Endocytosis | GTP Phosphohydrolases | Humans | Intracellular Signaling Peptides and Proteins | Mice | Molecular Sequence Data | Nerve Tissue Proteins | Phosphoproteins | Phosphoric Monoester Hydrolases | Protein Isoforms | Proteins | Tissue Distribution | Transferrin | Wiskott-Aldrich Syndrome Protein, Neuronal
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