Authors
Sheng-Ping Hsu, Daniel J Dickinson
Published in
Proceedings of the National Academy of Sciences of the United States of America. Volume 123. Issue 26. Pages e2509713123. Jun 30, 2026. Epub Jun 22, 2026.
Abstract
Cell polarity is essential for the formation and function of animal tissues. Atypical protein kinase C (aPKC), its cofactor PAR-6, and scaffold protein PAR-3 regulate cell polarity in many different animal cell types. PAR-3 oligomerization is important to establish cell polarity, but how oligomerization relates to the assembly of the PAR-3/aPKC/PAR-6 complex is still unclear. Here, we use in vivo and ex vivo single-molecule techniques to demonstrate cooperativity between PAR-3 oligomerization and its binding to aPKC/PAR-6 in the Caenorhabditis elegans zygote. Using genetic perturbations, we present evidence that aPKC and PAR-6 have independent binding sites for PAR-3. We propose that multivalency drives cooperativity because a single aPKC/PAR-6 heterodimer can interact simultaneously with multiple PAR-3 molecules in an oligomer. Although single binding site mutations do not fully eliminate PAR-3/aPKC/PAR-6 binding, they do abolish anterior-posterior polarity, suggesting that PAR-3/aPKC cooperativity contributes to PAR-3 function during polarity establishment. Finally, PAR-3/aPKC cooperativity is downregulated in polarity maintenance, and this downregulation depends on the mitotic kinase PLK-1. Together, our results show how cells can developmentally regulate multivalent assembly of a key polarity complex to achieve timely segregation of cell fate determinants.
PMID:
42330287
Bibliographic data and abstract were imported from PubMed on 23 Jun 2026.
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