Binding to PKC-3, but not to PAR-3 or to a conventional PDZ domain ligand, is required for PAR-6 function in C. elegans

作者：Li Jin; Kim Heon; Aceto Donato G; Hung Jeffrey; Aono Shinya; Kemphues Kenneth J^*

来源：Developmental Biology, 2010, 340(1): 88-98.

DOI：10.1016/j.ydbio.2010.01.023

• Embryogenesis
• Embryonic polarity
• Cell polarity
• Asymmetric division
• Atypical protein kinase

PAR-6 is a conserved protein important for establishment and maintenance of cell polarity in a variety of metazoans. PAR-6 proteins function together with PAR-3, aPKC and CDC-42. Mechanistic details of their interactions, however, are not fully understood. We studied the biochemical interactions between C. elegans PAR-6 and its binding partners and tested the requirements of these interactions in living worms. We show that PB1 domain-mediated binding of PAR-6 to PKC-3 is necessary for polarity establishment and PAR-6 cortical localization in C. elegans embryos. We also show that binding of PAR-6 and PAR-3 is mediated in vitro by a novel type of PDZ-PDZ interaction; the beta C strand of PAR-6 PDZ binds the beta D strand of PAR-3 PDZ1. However, this interaction is dispensable in vivo for PAR-6 function throughout the life of C elegans. Mutations that specifically abolish conventional ligand binding to the PAR-6 PDZ domain also failed to affect PAR-6 function in vivo. We conclude that PAR-6 binding to PKC-3, but not to PAR-3 nor to a conventional PDZ ligand, is required for PAR-6 cortical localization and function in C elegans.

• 出版日期2010-4-1