First published online November 9, 2007
Development 134, 2306e (2007)
© The Company of Biologists Limited
Polarity proteins seal cell fate
Cell polarity is thought to generate cell fate diversity through asymmetric
cell divisions, but which components of polarized cells convert polarity
information into cell fate determination? On
p. 4297, Sergei Sokol
and co-workers report that the answer in Xenopus epidermal ectoderm
is the conserved polarity proteins atypical protein kinase (aPKC) and
partitioning-defective 1 (PAR1). Early asymmetric divisions in
Xenopus embryos produce superficial (apical) and deep (basal)
ectodermal layers. These contain superficial epidermal cells and ciliated
cells, respectively. In gain- and loss-of-function studies, the researchers
show that aPKC, which is localized to the apical domain of the superficial
cells, inhibits ciliated cell differentiation and promotes superficial cell
fates. aPKC, they report, phosphorylates PAR1 and targets it to the
basolateral domain of the superficial cells and PAR1, they show, stimulates
ciliated cell differentiation and inhibits superficial epidermal cell fates,
possibly through Notch signalling. This aPKC/PAR1 pathway, the researchers
suggest, may link cell polarity to cell fate determination in epithelial
tissues in many species.
Related articles in Development:
- PAR1 specifies ciliated cells in vertebrate ectoderm downstream of aPKC
- Olga Ossipova, Jacqui Tabler, Jeremy B. A. Green, and Sergei Y. Sokol
Development 2007 134: 4297-4306.
[Abstract]
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