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The polarity‐inducing kinase Par‐1 controls Xenopus gastrulation in cooperation with 14‐3‐3 and aPKC
Author(s) -
Kusakabe Morioh,
Nishida Eisuke
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600381
Subject(s) - biology , xenopus , gastrulation , polarity (international relations) , microbiology and biotechnology , kinase , embryo , genetics , gene , embryogenesis , cell
Par ( partitioning‐defective ) genes were originally identified in Caenorhabditis elegans as determinants of anterior/posterior polarity. However, neither their function in vertebrate development nor their action mechanism has been fully addressed. Here we show that two members of Par proteins, 14‐3‐3 (Par‐5) and atypical PKC (aPKC), regulate the serine/threonine kinase Par‐1 to control Xenopus gastrulation. We find first that Xenopus Par‐1 (xPar‐1) is essential for gastrulation but not for cell fate specification during early embryonic development. We then find that xPar‐1 binds to 14‐3‐3 in an aPKC‐dependent manner. Our analyses identify two aPKC phosphorylation sites in xPar‐1, which are essential for 14‐3‐3 binding and for proper gastrulation movements. The aPKC phosphorylation‐dependent binding of xPar‐1 to 14‐3‐3 does not markedly affect the kinase activity of xPar‐1, but induces relocation of xPar‐1 from the plasma membranes to the cytoplasm. Finally, we show that Xenopus aPKC and its binding partner Xenopus Par‐6 are also essential for gastrulation. Thus, our results identify a requirement of Par proteins for Xenopus gastrulation and reveal a novel interrelationship within Par proteins that may provide a general mechanism for spatial control of Par‐1.