Nature Cell Biology2, 531 - 539 (2000)
Published online: 17 July 2000; | doi:10.1038/35019573
The cell-polarity protein Par6 links Par3 and atypical protein kinase
C to Cdc42
Gérard Joberty, Clark Petersen, Lin Gao
& Ian G. Macara
Markey Center for Cell Signaling, University of Virginia
Health Sciences Center, Charlottesville, Virginia
22908-0577, USA
gmj4h@virginia.edu
PAR (partitioning-defective) proteins, which were first identified in the
nematode Caenorhabditis elegans, are essential for asymmetric cell
division and polarized growth, whereas Cdc42 mediates establishment of cell
polarity. Here we describe an unexpected link between these two systems. We
have identified a family of mammalian Par6 proteins that are similar to the
C. elegans PDZ-domain protein PAR-6. Par6 forms a complex with Cdc42−GTP,
with a human homologue of the multi-PDZ protein PAR-3 and with the regulatory
domains of atypical protein kinase C (PKC) proteins. This assembly is implicated
in the formation of normal tight junctions at epithelial cell−cell contacts.
Thus, Par6 is a key adaptor that links Cdc42 and atypical PKCs to Par3.
