Inhibition of H-Ras and MAPK is compensated by PKC-dependent pathways in annexin A6 expressing cells
High-density lipoprotein (HDL)-induced activation of the Ras/MAPK pathway can be mediated by protein kinase C (PKC)-dependent and independent pathways. Although both pathways co-exist in cells, we showed that binding of HDL to scavenger receptor BI (SR-BI) in CHO cells activates Ras and MAPK in a PKC-independent manner. We have recently identified that HDL-induced activation of Ras and Raf-1 is reduced in annexin A6 expressing CHO cells (CHOanx6). In the present study we demonstrate that despite the loss of Ras and Raf-1 activity, HDL induces MAPK phosphorylation in CHOanx6 cells. Since annexin A6 is a PKCalpha-binding protein we therefore investigated the possible involvement of PKC in HDL-induced Ras and MAPK activation in CHOanx6 cells. Taken together our findings demonstrate that HDL-induced H-Ras and MAPK activation is PKC-dependent in cells expressing annexin A6 to compensate for the loss of PKC-independent activation of H-Ras and MAPK.
|Authors||Rentero, C.;Evans, R.;Wood, P.;Tebar, F.;Vila de Muga, S.;Cubells, L.;de Diego, I.;Hayes, T. E.;Hughes, W. E.;Pol, A.;Rye, K. A.;Enrich, C.;Grewal, T. :|
|Publisher Name||CELLULAR SIGNALLING|
|URL link to publisher's version||http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=16183252|