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Molecular basis for association of PIPKI gamma-p90 with clathrin adaptor AP-2

Item Type:Article
Title:Molecular basis for association of PIPKI gamma-p90 with clathrin adaptor AP-2
Creators Name:Kahlfeldt, N. and Vahedi-Faridi, A. and Koo, S.J. and Schaefer, J.G. and Krainer, G. and Keller, S. and Saenger, W. and Krauss, M. and Haucke, V.
Abstract:Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P(2)) is an essential determinant in clathrin-mediated endocytosis (CME). In mammals three type I phosphatidylinositol-4-phosphate 5-kinase (PIPK) enzymes are expressed, with the I gamma-p90 isoform being highly expressed in the brain where it regulates synaptic vesicle (SV) exo-/endocytosis at nerve terminals. How precisely PI(4,5)P(2) metabolism is controlled spatially and temporally is still uncertain, but recent data indicate that direct interactions between type I PIPK and components of the endocytic machinery, in particular the AP-2 adaptor complex, are involved. Here we demonstrated that PIPKI gamma-p90 associates with both the mu and beta2 subunits of AP-2 via multiple sites. Crystallographic data show that a peptide derived from the splice insert of the human PIPKI gamma-p90 tail binds to a cognate recognition site on the sandwich subdomain of the beta2 appendage. Partly overlapping aromatic and hydrophobic residues within the same peptide also can engage the C-terminal sorting signal binding domain of AP-2mu, thereby potentially competing with the sorting of conventional YXXØ motif-containing cargo. Biochemical and structure-based mutagenesis analysis revealed that association of the tail domain of PIPKI gamma-p90 with AP-2 involves both of these sites. Accordingly the ability of overexpressed PIPKI gamma tail to impair endocytosis of SVs in primary neurons largely depends on its association with AP-2 beta and AP-2mu. Our data also suggest that interactions between AP-2 and the tail domain of PIPKI gamma-p90 may serve to regulate complex formation and enzymatic activity. We postulate a model according to which multiple interactions between PIPKI gamma-p90 and AP-2 lead to spatiotemporally controlled PI(4,5)P(2) synthesis during clathrin-mediated SV endocytosis.
Keywords:Cell, Membrane, Clathrin, Phosphatidylinositol Kinase, Synaptic Vesicle Recycling, Animals, Rabbits, Rats
Source:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology
Page Range:2734-2749
Date:22 January 2010
Official Publication:https://doi.org/10.1074/jbc.M109.074906
PubMed:View item in PubMed

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