The atypical protein kinase C (aPKC) is required for the polarisation of many cell types and has important roles in neural stem cell identity and proliferation. Yet, despite its importance for cell polarity and growth,little is known about how its activity is regulated. Now Chabu and Doe (on ) report that,in Drosophila, Dynamin-associated protein 160 (Dap160) positively regulates aPKC, and that aPKC requires it to establish neuroblast (NB) cell polarity and cell cycle progression. The authors identified Dap160 by performing immunoprecipitation experiments coupled to mass spectrometry using aPKC as the bait. They show that Dap160 directly interacts with aPKC and stimulates its activity in vitro. In vivo, it colocalises with aPKC at the apical cortex of embryonic NBs; in dap160 mutants, aPKC delocalises from here and has reduced activity. In addition, in both dap160 and aPKC mutants, fewer proliferating NBs with a prolonged cell cycle are found. Exactly how Dap160 localises aPKC and promotes cell cycle progression remain questions for the future.
