Developmental Cell
Volume 42, Issue 4, 21 August 2017, Pages 400-415.e9
Journal home page for Developmental Cell

Article
aPKC Cycles between Functionally Distinct PAR Protein Assemblies to Drive Cell Polarity

https://doi.org/10.1016/j.devcel.2017.07.007Get rights and content
Under a Creative Commons license
open access

Highlights

  • Distinct aPKC-containing assemblies respond to cues and generate polarity signals

  • Clustering of aPAR proteins on the membrane enables segregation by cortical flow

  • PAR-3 promotes both loading and polarization of aPKC but limits its activity in vivo

  • aPKC activity links cue-sensing and effector assemblies to drive efficient polarization

Summary

The conserved polarity effector proteins PAR-3, PAR-6, CDC-42, and atypical protein kinase C (aPKC) form a core unit of the PAR protein network, which plays a central role in polarizing a broad range of animal cell types. To functionally polarize cells, these proteins must activate aPKC within a spatially defined membrane domain on one side of the cell in response to symmetry-breaking cues. Using the Caenorhabditis elegans zygote as a model, we find that the localization and activation of aPKC involve distinct, specialized aPKC-containing assemblies: a PAR-3-dependent assembly that responds to polarity cues and promotes efficient segregation of aPKC toward the anterior but holds aPKC in an inactive state, and a CDC-42-dependent assembly in which aPKC is active but poorly segregated. Cycling of aPKC between these distinct functional assemblies, which appears to depend on aPKC activity, effectively links cue-sensing and effector roles within the PAR network to ensure robust establishment of polarity.

Keywords

cell polarity
PAR proteins
atypical protein kinase C
symmetry breaking
actomyosin flow
PAR clusters
PAR-3
PAR-6
CDC-42
PKC-3

Cited by (0)

6

These authors contributed equally

7

Lead Contact