Author: ["Fumio Motegi","Seth Zonies","Yingsong Hao","Adrian A. Cuenca","Erik Griffin","Geraldine Seydoux"]
CITE.CC academic search helps you expand the influence of your papers.
Abstract
PAR polarity proteins are asymmetrically localized at the cortex of Caenorhabditis elegans zygotes. Seydoux and colleagues show that aPKC-mediated phosphorylation of PAR-2, which inhibits recruitment of PAR-2 to the cortex, is directly inhibited by microtubules emanating from the sperm-donated centrosomes. This protection allows PAR-2, and subsequently the PAR-1 kinase to access the cortex nearby the sperm, thus defining the posterior of the embryo. PAR-1 in turn phosphorylates PAR-3 to induce dissociation of PAR-3–aPKC from the posterior. A hallmark of polarized cells is the segregation of the PAR polarity regulators into asymmetric domains at the cell cortex1,2. Antagonistic interactions involving two conserved kinases, atypical protein kinase C (aPKC) and PAR-1, have been implicated in polarity maintenance1,2, but the mechanisms that initiate the formation of asymmetric PAR domains are not understood. Here, we describe one pathway used by the sperm-donated centrosome to polarize the PAR proteins in Caenorhabditis elegans zygotes. Before polarization, cortical aPKC excludes PAR-1 kinase and its binding partner PAR-2 by phosphorylation. During symmetry breaking, microtubules nucleated by the centrosome locally protect PAR-2 from phosphorylation by aPKC, allowing PAR-2 and PAR-1 to access the cortex nearest the centrosome. Cortical PAR-1 phosphorylates PAR-3, causing the PAR-3–aPKC complex to leave the cortex. Our findings illustrate how microtubules, independently of actin dynamics, stimulate the self-organization of PAR proteins by providing local protection against a global barrier imposed by aPKC.Cite this article
Motegi, F., Zonies, S., Hao, Y. et al. Microtubules induce self-organization of polarized PAR domains in Caenorhabditis elegans zygotes. Nat Cell Biol 13, 1361–1367 (2011). https://doi.org/10.1038/ncb2354 