Location and functional significance of retinol-binding sites on the serine/threonine kinase, c-Raf Journal Article
| Authors: | Hoyos, B.; Jiang, S.; Hammerling, U. |
| Article Title: | Location and functional significance of retinol-binding sites on the serine/threonine kinase, c-Raf |
| Abstract: | Redox activations of serine/threonine kinases represent alternate pathways in which vitamin A plays a crucial co-factor role. Vitamin A binds the zinc finger domain of c-Raf with nanomolar affinity. The retinoid-binding site has been mapped within this structure by scanning mutagenesis. The deduced contact sites were found anchored on Phe-8, counting from the 1st conserved histidine of the zinc finger. These sites agreed with contact amino acids identified by computational docking. The boundaries of a related binding pocket were identified by mutagenesis and partially confirmed by docking trials in the protein kinase C-α C1A zinc finger. They comprised Phe-7, Phe-8, and Trp-22. This trio was absent from the αC1B domain, explaining why the latter did not bind retinol. Reconfiguring at a minimum the two corresponding amino acids of αC1B, Thr-7 and Tyr-22, to conform to αC1A converted this domain to a binder. Deletion of the predicted retinoid-binding site in the full-length molecule created a mutant c-Raf that was deficient in retinol-dependent redox activation but fully responsive to epidermal growth factor. Our findings indicate that ligation of retinol to a specific site embedded in the regulatory domain is an important feature of c-Raf regulation in the redox pathway. © 2005 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Keywords: | epidermal growth factor; controlled study; sequence deletion; raf protein; nonhuman; mutant protein; binding affinity; protein domain; proteins; animal cell; animals; mice; protein binding; enzyme activation; transfection; protein serine threonine kinase; tyrosine; cos cells; amino acid sequence; protein-serine-threonine kinases; binding site; threonine; protein kinase c; binding energy; binding sites; amino acids; retinol; zinc; mutagenesis; enzymes; oxidation reduction reaction; oxidation-reduction; histidine; phenylalanine; protein kinase c alpha; zinc finger motif; protein kinase c-alpha; proto-oncogene proteins c-raf; vitamin a; zinc fingers; vitamins; redox reactions; computational docking; nanomolar affinity; retinol-binding sites; vitamin metabolism |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 280 |
| Issue: | 8 |
| ISSN: | 0021-9258 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Date Published: | 2005-02-25 |
| Start Page: | 6872 |
| End Page: | 6878 |
| Language: | English |
| DOI: | 10.1074/jbc.M412695200 |
| PUBMED: | 15591313 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 13" - "Export Date: 24 October 2012" - "CODEN: JBCHA" - "Source: Scopus" |
