An aPKC-exocyst complex controls paxillin phosphorylation and migration through localised JNK1 activation.
Atypical protein kinase C (aPKC) isoforms have been implicated in cell polarisation and migration through association with Cdc42 and Par6. In distinct migratory models, the Exocyst complex has been shown to be involved in secretory events and migration. By RNA interference (RNAi) we show that the polarised delivery of the Exocyst to the leading edge of migrating NRK cells is dependent upon aPKCs. Reciprocally we demonstrate that aPKC localisation at the leading edge is dependent upon the Exocyst. The basis of this inter-dependence derives from two-hybrid, mass spectrometry, and co-immunoprecipitation studies, which demonstrate the existence of an aPKC-Exocyst interaction mediated by Kibra. Using RNAi and small molecule inhibitors, the aPKCs, Kibra, and the Exocyst are shown to be required for NRK cell migration and it is further demonstrated that they are necessary for the localized activation of JNK at the leading edge. The migration associated control of JNK by aPKCs determines JNK phosphorylation of the plasma membrane substrate Paxillin, but not the phosphorylation of the nuclear JNK substrate, c-jun. This plasma membrane localized JNK cascade serves to control the stability of focal adhesion complexes, regulating migration. The study integrates the polarising behaviour of aPKCs with the pro-migratory properties of the Exocyst complex, defining a higher order complex associated with the localised activation of JNK at the leading edge of migrating cells that determines migration rate.
Rosse
Carine
C
Protein Phosphorylation Laboratory, Cancer Research UK London Research Institute, London, United Kingdom.
Formstecher
Etienne
E
Boeckeler
Katrina
K
Zhao
Yingming
Y
Kremerskothen
Joachim
J
White
Michael D
MD
Camonis
Jacques H
JH
Parker
Peter J
PJ
D000818:Animals; D015153:Blotting, Western; D002227:Carbazoles / Q000494:pharmacology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement; D002478:Cells, Cultured; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis; D022001:Focal Adhesions / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D051419:Paxillin / Q000378:metabolism*; D010750:Phosphoproteins; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D020798:Two-Hybrid System Techniques
D002227:Carbazoles; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; C076326:Exoc4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051419:Paxillin; D010750:Phosphoproteins; D011506:Proteins; C513637:WWC1 protein, human; C081021:Go 6976; C115015:PKC-3 protein; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048055:Mitogen-Activated Protein Kinase 8; D020929:Mitogen-Activated Protein Kinase Kinases