Publication Date:
1994-06-03
Description:
The small guanine nucleotide binding protein Ras participates in a growth promoting signal transduction pathway. The mechanism by which interaction of Ras with the protein kinase Raf leads to activation of Raf was studied. Raf was targeted to the plasma membrane by addition of the COOH-terminal localization signals of K-ras. This modified form of Raf (RafCAAX) was activated to the same extent as Raf coexpressed with oncogenic mutant Ras. Plasma membrane localization rather than farnesylation or the presence of the additional COOH-terminal sequence accounted for the activation of RafCAAX. The activation of RafCAAX was completely independent of Ras; it was neither potentiated by oncogenic mutant Ras nor abrogated by dominant negative Ras. Raf, once recruited to the plasma membrane, was not anchored there by Ras; most activated Raf in cells was associated with plasma membrane cytoskeletal elements, not the lipid bilayer. Thus, Ras functions in the activation of Raf by recruiting Raf to the plasma membrane where a separate, Ras-independent, activation of Raf occurs.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Stokoe, D -- Macdonald, S G -- Cadwallader, K -- Symons, M -- Hancock, J F -- New York, N.Y. -- Science. 1994 Jun 3;264(5164):1463-7.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉ONXY Pharmaceuticals, Richmond, CA 94806.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7811320" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Animals
;
Cell Line
;
Cell Membrane/*enzymology
;
Cytosol/enzymology
;
Enzyme Activation
;
GTP-Binding Proteins/*metabolism
;
MAP Kinase Kinase 1
;
Mitogen-Activated Protein Kinase 1
;
*Mitogen-Activated Protein Kinase Kinases
;
Models, Biological
;
Molecular Sequence Data
;
Protein-Serine-Threonine Kinases/chemistry/*metabolism
;
Protein-Tyrosine Kinases/metabolism
;
Proto-Oncogene Proteins/chemistry/*metabolism
;
Proto-Oncogene Proteins c-raf
;
Recombinant Fusion Proteins/metabolism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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