Serine 77 in the PDZ domain of PICK1 is a protein kinase Cα phosphorylation site regulated by lipid membrane binding
Research output: Contribution to journal › Journal article › peer-review
PICK1 (protein interacting with C kinase 1) contains an N-terminal protein binding PDZ domain and a C-terminal lipid binding BAR domain. PICK1 plays a key role in several physiological processes, including synaptic plasticity. However, little is known about the cellular mechanisms governing the activity of PICK1 itself. Here we show that PICK1 is a substrate in vitro both for PKCα (protein kinase Cα), as previously shown, and for CaMKIIα (Ca(2+)-calmodulin-dependent protein kinase IIα). By mutation of predicted phosphorylation sites, we identify Ser77 in the PDZ domain as a major phosphorylation site for PKCα. Mutation of Ser77 reduced the level of PKCα-mediated phosphorylation ~50%, whereas no reduction was observed upon mutation of seven other predicted sites. Addition of lipid vesicles increased the level of phosphorylation of Ser77 10-fold, indicating that lipid binding is critical for optimal phosphorylation. Binding of PKCα to the PICK1 PDZ domain was not required for phosphorylation, but a PDZ domain peptide ligand reduced the overall level of phosphorylation ~30%. The phosphomimic S77D reduced the extent of cytosolic clustering of eYFP-PICK1 in COS7 cells and thereby conceivably its lipid binding and/or polymerization capacity. We propose that PICK1 is phosphorylated at Ser77 by PKCα preferentially when bound to membrane vesicles and that this phosphorylation in turn modulates its cellular distribution.
Original language | English |
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Journal | Biochemistry |
Volume | 51 |
Issue number | 2 |
Pages (from-to) | 586-96 |
Number of pages | 11 |
DOIs | |
Publication status | Published - 17 Jan 2012 |
- Amino Acid Substitution, Animals, Binding Sites, COS Cells, Calcium-Calmodulin-Dependent Protein Kinase Type 2, Carrier Proteins, Cell Membrane, Cercopithecus aethiops, Lipid Metabolism, Models, Molecular, Mutagenesis, Site-Directed, Mutation, Nuclear Proteins, PDZ Domains, Phosphorylation, Protein Kinase C-alpha, Protein Transport, Serine
Research areas
ID: 46375150