Spatiotemporal analysis of the molecular interaction between PICK1 and PKC.

PICK1 is a protein which was initially identified as a protein kinase Calpha (alphaPKC) binding protein using the yeast two-hybrid system. In addition to alphaPKC, the PICK1 complex binds to and regulates various transmembrane proteins including receptors and transporters. However, it has not been clarified when and where PICK1 binds to alphaPKC. We examined the spatio-temporal interaction of PICK1 and PKC using live imaging techniques and showed that the activated alphaPKC binds to PICK1 and transports it to the plasma membrane. Although the membrane translocation of PICK1 requires the activation of alphaPKC, PICK1 is retained on the membrane even after PKC moves back to the cytosol. These results suggest that the interaction between alphaPKC and PICK1 is transient and may not be necessary for the regulation of receptors/transporters by PICK1 or by alphaPKC on the membrane.