scholarly journals Rap1 and Canoe/afadin are essential for establishment of apical–basal polarity in the Drosophila embryo

2013 ◽  
Vol 24 (7) ◽  
pp. 945-963 ◽  
Author(s):  
Wangsun Choi ◽  
Nathan J. Harris ◽  
Kaelyn D. Sumigray ◽  
Mark Peifer
Keyword(s):  
Protein Kinase C ◽  
Cell Polarity ◽  
Cell Shape ◽  
Adherens Junctions ◽  
Small Gtpase ◽  
Drosophila Embryo ◽  
Current View ◽  
Kinase C ◽  
Polarity Establishment ◽  
Drosophila Embryos

The establishment and maintenance of apical–basal cell polarity is critical for assembling epithelia and maintaining organ architecture. Drosophila embryos provide a superb model. In the current view, apically positioned Bazooka/Par3 is the initial polarity cue as cells form during cellularization. Bazooka then helps to position both adherens junctions and atypical protein kinase C (aPKC). Although a polarized cytoskeleton is critical for Bazooka positioning, proteins mediating this remained unknown. We found that the small GTPase Rap1 and the actin-junctional linker Canoe/afadin are essential for polarity establishment, as both adherens junctions and Bazooka are mispositioned in their absence. Rap1 and Canoe do not simply organize the cytoskeleton, as actin and microtubules become properly polarized in their absence. Canoe can recruit Bazooka when ectopically expressed, but they do not obligatorily colocalize. Rap1 and Canoe play continuing roles in Bazooka localization during gastrulation, but other polarity cues partially restore apical Bazooka in the absence of Rap1 or Canoe. We next tested the current linear model for polarity establishment. Both Bazooka and aPKC regulate Canoe localization despite being “downstream” of Canoe. Further, Rap1, Bazooka, and aPKC, but not Canoe, regulate columnar cell shape. These data reshape our view, suggesting that polarity establishment is regulated by a protein network rather than a linear pathway.

E-cadherin mediates adherens junction organization through protein kinase C

1994 ◽  
Vol 107 (12) ◽  
pp. 3615-3621 ◽  
Author(s):  
J.E. Lewis ◽  
P.J. Jensen ◽  
K.R. Johnson ◽  
M.J. Wheelock
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Adherens Junctions ◽  
Adherens Junction ◽  
Human Keratinocytes ◽  
Kinase C ◽  
E Cadherin

Cultured human keratinocytes maintained in 30 microM Ca2+ do not form adherens junctions; however, when the extracellular Ca2+ concentration is raised to 1 mM, adherens junctions form very rapidly. The formation of a junction involves the coordinate organization of intracellular and extracellular components. Cadherins have been shown to mediate this coordinate organization. In this report we show that E-cadherin organizes the various junctional components by signalling through protein kinase C.

The cell-polarity protein Par6 links Par3 and atypical protein kinase C to Cdc42

2000 ◽  
Vol 2 (8) ◽  
pp. 531-539 ◽  
Author(s):  
Gérard Joberty ◽  
Clark Petersen ◽  
Lin Gao ◽  
Ian G. Macara
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Polarity ◽  
Atypical Protein Kinase C ◽  
Atypical Protein Kinase ◽  
Kinase C

scholarly journals Involvement of integrin-induced activation of protein kinase C in the formation of adherens junctions

2007 ◽  
Vol 12 (5) ◽  
pp. 651-662 ◽  
Author(s):  
Misa Ozaki ◽  
Hisakazu Ogita ◽  
Yoshimi Takai
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Adherens Junctions ◽  
Kinase C

scholarly journals CalDAG-GEFI and protein kinase C represent alternative pathways leading to activation of integrin αIIbβ3 in platelets

Blood ◽  
2008 ◽  
Vol 112 (5) ◽  
pp. 1696-1703 ◽  
Author(s):  
Stephen M. Cifuni ◽  
Denisa D. Wagner ◽  
Wolfgang Bergmeier
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Small Gtpase ◽  
Wild Type ◽  
Pkc Inhibitor ◽  
Integrin Αiibβ3 ◽  
Alternative Pathways ◽  
Kinase C ◽  
Induced Aggregation ◽  
Inside Out

AbstractSecond messenger-mediated inside-out activation of integrin αIIbβ3 is a key step in platelet aggregation. We recently showed strongly impaired but not absent αIIbβ3-mediated aggregation of CalDAG-GEFI–deficient platelets activated with various agonists. Here we further evaluated the roles of CalDAG-GEFI and protein kinase C (PKC) for αIIbβ3 activation in platelets activated with a PAR4 receptor–specific agonist, GYPGKF (PAR4p). Compared with wild-type controls, platelets treated with the PKC inhibitor Ro31-8220 or CalDAG-GEFI–deficient platelets showed a marked defect in aggregation at low (< 1mM PAR4p) but not high PAR4p concentrations. Blocking of PKC function in CalDAG-GEFI–deficient platelets, how-ever, strongly decreased aggregation at all PAR4p concentrations, demonstrating that CalDAG-GEFI and PKC represent separate, but synergizing, pathways important for αIIbβ3 activation. PAR4p-induced aggregation in the absence of CalDAG-GEFI required cosignaling through the Gαi-coupled receptor for ADP, P2Y12. Independent roles for CalDAG-GEFI and PKC/Gαi signaling were also observed for PAR4p-induced activation of the small GTPase Rap1, with CalDAG-GEFI mediating the rapid but reversible activation of this small GTPase. In summary, our study identifies CalDAG-GEFI and PKC as independent pathways leading to Rap1 and αIIbβ3 activation in mouse platelets activated through the PAR4 receptor.

scholarly journals Atypical protein kinase C controls sea urchin ciliogenesis

2011 ◽  
Vol 22 (12) ◽  
pp. 2042-2053 ◽  
Author(s):  
Gérard Prulière ◽  
Jacky Cosson ◽  
Sandra Chevalier ◽  
Christian Sardet ◽  
Janet Chenevert
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Cell Polarity ◽  
Sea Urchin ◽  
Primary Cilium ◽  
Atypical Protein Kinase C ◽  
Atypical Protein Kinase ◽  
Kinase C ◽  
Motile Cilia ◽  
Sensory Processes

The atypical protein kinase C (aPKC) is part of the conserved aPKC/PAR6/PAR3 protein complex, which regulates many cell polarity events, including the formation of a primary cilium at the apical surface of epithelial cells. Cilia are highly organized, conserved, microtubule-based structures involved in motility, sensory processes, signaling, and cell polarity. We examined the distribution and function of aPKC in the sea urchin embryo, which forms a swimming blastula covered with motile cilia. We found that in the early embryo aPKC is uniformly cortical and becomes excluded from the vegetal pole during unequal cleavages at the 8- to 64-cell stages. During the blastula and gastrula stages the kinase localizes at the base of cilia, forming a ring at the transition zone between the basal body and the elongating axoneme. A dose-dependent and reversible inhibition of aPKC results in mislocalization of the kinase, defective ciliogenesis, and lack of swimming. Thus, as in the primary cilium of differentiated mammalian cells, aPKC controls the growth of motile cilia in invertebrate embryos. We suggest that aPKC might function to phosphorylate kinesin and so activate the transport of intraflagellar vesicles.

Sign in / Sign up

Export Citation Format

Share Document