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PICK1: a perinuclear binding protein and substrate for protein kinase C isolated by the yeast two-hybrid system
J Staudinger1, J Zhou, R Burgess
1Department of Biochemistry and Molecular Biology, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Abstract:
Protein kinase C (PKC) plays a central role in the control of proliferation and differentiation of a wide range of cell types by mediating the signal transduction response to hormones and growth factors. Upon activation by diacylglycerol, PKC translocates to different subcellular sites where it phosphorylates numerous proteins, most of which are unidentified. We used the yeast two-hybrid system to identify proteins that interact with activated PKC alpha. Using the catalytic region of PKC fused to the DNA binding domain of yeast GAL4 as "bait" to screen a mouse T cell cDNA library in which cDNA was fused to the GAL4 activation domain, we cloned several novel proteins that interact with C-kinase (PICKs). One of these proteins, designated PICK1, interacts specifically with the catalytic domain of PKC and is an efficient substrate for phosphorylation by PKC in vitro and in vivo. PICK1 is localized to the perinuclear region and is phosphorylated in response to PKC activation. PICK1 and other PICKs may play important roles in mediating the actions of PKC.
Insights
Researchers identified novel proteins interacting with Protein Kinase C alpha (PKC). One protein, PICK1, binds to PKC, is phosphorylated by it, and may mediate PKC signaling pathways in cell proliferation and differentiation.
Area of Science:
- Molecular Biology
- Cell Signaling
- Biochemistry
Background:
- Protein Kinase C (PKC) is crucial for cell proliferation and differentiation, mediating signal transduction.
- Activated PKC translocates within cells and phosphorylates numerous, often unidentified, target proteins.
- Understanding PKC interactions is key to deciphering its role in cellular processes.
Purpose of the Study:
- To identify novel proteins that interact with activated Protein Kinase C alpha (PKCα).
- To characterize the interaction and function of these novel PKC-interacting proteins (PICKs).
Main Methods:
- Yeast two-hybrid system was employed to screen for interacting proteins.
- The catalytic region of PKCα was used as bait against a mouse T cell cDNA library.
- Interaction specificity and phosphorylation status of identified proteins were analyzed.
Main Results:
- Several novel proteins interacting with PKCα were identified and designated PICKs.
- One identified protein, PICK1, specifically interacts with the PKC catalytic domain.
- PICK1 is an efficient substrate for PKC phosphorylation both in vitro and in vivo, and is localized to the perinuclear region.
Conclusions:
- PICK1 is a novel PKC-binding protein and a substrate for PKC.
- PICK1 and other PICKs are likely involved in mediating the cellular actions of PKC.
- These findings provide new insights into the molecular mechanisms of PKC signaling pathways.