Cell Asymmetry

Asymmetry at Maturation

Science's STKE  07 Nov 2000:
Vol. 2000, Issue 57, pp. tw6
DOI: 10.1126/stke.2000.57.tw6

The atypical isotype of protein kinase C (aPKC) has a role in polarization in mammalian cells. Along with an adaptor, the PDZ domain-containing protein ASIP (atypical PKC isotype-specific interacting protein), aPKC is localized to tight junctions in epithelial cells. In Caenorhabditis elegans, aPKC and the ASIP homolog PAR-3 are asymmetrically localized in one-celled embryos. Nakaya et al. studied the localization of Xenopus aPKC (XaPKC) and its ASIP-binding protein. In immature oocytes, the proteins were distributed uniformly, but progesterone-induced maturation caused localization of the complex to the animal hemisphere of mature oocytes. A point mutation in the ATP-binding site of XaPKC blocked this redistribution, indicating that activity of the kinase is required. Further analysis of the regulated redistribution of XaPKC may enhance our understanding of the highly conserved roles of aPKC and ASIP in generating cell asymmetry in very different biological contexts in organisms ranging from C. elegans to mammals.

Nakaya, M.-a., Fukui, A., Izumi, Y., Akimoto, K., Asashima, M., and Ohno, S. (2000) Meiotic maturation induces animal-vegetal symmetric distribution of aPKC and ASIP/PAR-3 in Xenopus oocytes. Development 127:5021-5031. [Online Journal]