Protein kinase N3 (PKN3) is a serine/threonine kinase implicated in tumor progression of multiple cancer types, however, its substrates and effector proteins still remain largely understudied. In the present work we aimed to identify novel PKN3 substrates in a phosphoproteomic screen using analog sensitive PKN3. Among the identified putative substrates we selected ARHGAP18, a protein from RhoGAP family, for validation of the screen and further study. We confirmed that PKN3 can phosphorylate ARHGAP18 in vitro and we also characterized the interaction of the two proteins, which is mediated via the N-terminal part of ARHGAP18. We present strong evidence that PKN3-ARHGAP18 interaction is increased upon ARHGAP18 phosphorylation and that the phosphorylation of ARHGAP18 by PKN3 enhances its GAP domain activity and contributes to negative regulation of active RhoA. Taken together, we identified new set of potential PKN3 substrates and revealed a new negative feedback regulatory mechanism of Rho signaling mediated by PKN3-induced ARHGAP18 activation.

• Klíčová slova
• ARHGAP18, PKN3, Rho-GTP, phosphoproteomic screen, phosphorylation,
• MeSH
• fosforylace MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• proteinkinasa C genetika   metabolismus   MeSH
• proteiny aktivující GTPasu metabolismus   MeSH
• proteomika metody   MeSH
• sekvence aminokyselin MeSH
• signální transdukce MeSH
• substrátová specifita MeSH
• vazba proteinů MeSH
• zpětná vazba fyziologická MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ARHGAP18 protein, human MeSH Prohlížeč
• protein kinase N MeSH Prohlížeč
• proteinkinasa C MeSH
• proteiny aktivující GTPasu MeSH