Functional crosstalk between Cdc42 and two downstream targets Par6B and PAK4

The establishment of polarity is an essential step in epithelial morphogenesis. Polarity proteins promote an apical/basal axis, which together with the assembly of apical adherens and tight junctions, directed vesicle transport, and the reorganization of the actomyosin filament network generate a stable epithelium. The regulation of these cellular activities is complex, but the Rho family GTPase Cdc42 is known to play a key role in the establishment of polarity from yeast to man. We previously identified two Cdc42 target proteins, the kinase PAK4 and the scaffold Par6B, required to promote the assembly of apical junctions in human bronchial epithelial cells. We show here that PAK4 phosphorylates Par6B at Ser-143 blocking its interaction with Cdc42. This provides a potential new mechanism for controlling the sub-cellular localization of Par6B and its interaction with other proteins.

Source: BJ Signal - February 9, 2015 Category: Biochemistry Authors: D Jin, J Durgan, A Hall Tags: BJ Signal Source Type: research