Publications

Abstract

In this study, we describe a new post-translational modification at position -1 of the PDZ-binding motif in the Mutated in Colorectal Cancer protein and its role in lamellipodia formation. The Serine 828 at position -1 of this motif is phosphorylated, which is predicted to increase MCC binding affinity with the polarity protein Scrib. We show that endogenous MCC localises at the active migratory edge of cells, where it interacts with the polarity protein Scrib and the non-muscle motor protein Myosin-IIB. Expression of MCC harbouring a phosphomimetic mutation MCC-S828D strongly impaired lamellipodia formation and resulted in accumulation of Myosin-IIB in the membrane cortex fraction. We propose that MCC regulates lamellipodia formation by binding to Scrib and its downstream partner Myosin-IIB in a multiprotein complex. Importantly, we propose that the function of this complex is under the regulation of a newly described phosphorylation of the PDZ-binding motif at position -1.