| Structural highlights
Disease
[RAF1_HUMAN] Defects in RAF1 are the cause of Noonan syndrome type 5 (NS5) [MIM:611553]. Noonan syndrome (NS) is a disorder characterized by dysmorphic facial features, short stature, hypertelorism, cardiac anomalies, deafness, motor delay, and a bleeding diathesis. It is a genetically heterogeneous and relatively common syndrome, with an estimated incidence of 1 in 1000-2500 live births.[1] [2] [3] Defects in RAF1 are the cause of LEOPARD syndrome type 2 (LEOPARD2) [MIM:611554]. LEOPARD syndrome is an autosomal dominant disorder allelic with Noonan syndrome. The acronym LEOPARD stands for lentigines, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonic stenosis, abnormalities of genitalia, retardation of growth, and deafness.[4]
Function
[1433Z_HUMAN] Adapter protein implicated in the regulation of a large spectrum of both general and specialized signaling pathways. Binds to a large number of partners, usually by recognition of a phosphoserine or phosphothreonine motif. Binding generally results in the modulation of the activity of the binding partner.[5] [6] [7] [8] [9] [RAF1_HUMAN] Serine/threonine-protein kinase that acts as a regulatory link between the membrane-associated Ras GTPases and the MAPK/ERK cascade, and this critical regulatory link functions as a switch determining cell fate decisions including proliferation, differentiation, apoptosis, survival and oncogenic transformation. RAF1 activation initiates a mitogen-activated protein kinase (MAPK) cascade that comprises a sequential phosphorylation of the dual-specific MAPK kinases (MAP2K1/MEK1 and MAP2K2/MEK2) and the extracellular signal-regulated kinases (MAPK3/ERK1 and MAPK1/ERK2). The phosphorylated form of RAF1 (on residues Ser-338 and Ser-339, by PAK1) phosphorylates BAD/Bcl2-antagonist of cell death at 'Ser-75'. Phosphorylates adenylyl cyclases: ADCY2, ADCY5 and ADCY6, resulting in their activation. Phosphorylates PPP1R12A resulting in inhibition of the phosphatase activity. Phosphorylates TNNT2/cardiac muscle troponin T. Can promote NF-kB activation and inhibit signal transducers involved in motility (ROCK2), apoptosis (MAP3K5/ASK1 and STK3/MST2), proliferation and angiogenesis (RB1). Can protect cells from apoptosis also by translocating to the mitochondria where it binds BCL2 and displaces BAD/Bcl2-antagonist of cell death. Regulates Rho signaling and migration, and is required for normal wound healing. Plays a role in the oncogenic transformation of epithelial cells via repression of the TJ protein, occludin (OCLN) by inducing the up-regulation of a transcriptional repressor SNAI2/SLUG, which induces down-regulation of OCLN. Restricts caspase activation in response to selected stimuli, notably Fas stimulation, pathogen-mediated macrophage apoptosis, and erythroid differentiation.[10] [11] [12] [13] [14] [15] [16]
Publication Abstract from PubMed
C-RAF kinase is a central component of the Ras-RAF-MEK (mitogen-activated protein kinase/extracellular signal-regulated kinase)-ERK (extracellular signal-regulated kinase) pathway, which has been shown to be activated in 30% of human tumors. 14-3-3 proteins inactivate C-RAF by binding to the two N-terminal phosphorylation-dependent binding sites surrounding S233 and S259. 14-3-3 proteins can bind two target sequences located on one polypeptide chain simultaneously, thereby increasing binding affinity compared to single-site binding and possibly allowing regulated 14-3-3 binding through gatekeeper phosphorylation. To date, it was unclear whether 14-3-3 proteins can bind the two N-terminal phosphorylation-dependent binding site of C-RAF simultaneously. Fluorescence polarization using phosphorylated peptides demonstrated that S233 is the low-affinity and S259 is the high-affinity binding site, while simultaneous engagement of both sites by 14-3-3zeta enhances affinity compared to single-site binding. Determination of a 1:1 stoichiometry for the di-phosphorylatedpeptide binding to one 14-3-3zeta dimer with isothermal titration calorimetry was supported by the crystal structure of the 14-3-3zeta/C-RAFpS233,pS259 complex. Cellular localization studies validate the significance of these sites for cytoplasmic retention of C-RAF, suggesting an extended mechanism of RAF regulation by 14-3-3 proteins.
Synergistic Binding of the Phosphorylated S233- and S259-Binding Sites of C-RAF to One 14-3-3zeta Dimer.,Molzan M, Ottmann C J Mol Biol. 2012 Aug 24. PMID:22922483[17]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Pandit B, Sarkozy A, Pennacchio LA, Carta C, Oishi K, Martinelli S, Pogna EA, Schackwitz W, Ustaszewska A, Landstrom A, Bos JM, Ommen SR, Esposito G, Lepri F, Faul C, Mundel P, Lopez Siguero JP, Tenconi R, Selicorni A, Rossi C, Mazzanti L, Torrente I, Marino B, Digilio MC, Zampino G, Ackerman MJ, Dallapiccola B, Tartaglia M, Gelb BD. Gain-of-function RAF1 mutations cause Noonan and LEOPARD syndromes with hypertrophic cardiomyopathy. Nat Genet. 2007 Aug;39(8):1007-12. Epub 2007 Jul 1. PMID:17603483 doi:10.1038/ng2073
- ↑ Razzaque MA, Nishizawa T, Komoike Y, Yagi H, Furutani M, Amo R, Kamisago M, Momma K, Katayama H, Nakagawa M, Fujiwara Y, Matsushima M, Mizuno K, Tokuyama M, Hirota H, Muneuchi J, Higashinakagawa T, Matsuoka R. Germline gain-of-function mutations in RAF1 cause Noonan syndrome. Nat Genet. 2007 Aug;39(8):1013-7. Epub 2007 Jul 1. PMID:17603482 doi:ng2078
- ↑ Longoni M, Moncini S, Cisternino M, Morella IM, Ferraiuolo S, Russo S, Mannarino S, Brazzelli V, Coi P, Zippel R, Venturin M, Riva P. Noonan syndrome associated with both a new Jnk-activating familial SOS1 and a de novo RAF1 mutations. Am J Med Genet A. 2010 Sep;152A(9):2176-84. doi: 10.1002/ajmg.a.33564. PMID:20683980 doi:10.1002/ajmg.a.33564
- ↑ Pandit B, Sarkozy A, Pennacchio LA, Carta C, Oishi K, Martinelli S, Pogna EA, Schackwitz W, Ustaszewska A, Landstrom A, Bos JM, Ommen SR, Esposito G, Lepri F, Faul C, Mundel P, Lopez Siguero JP, Tenconi R, Selicorni A, Rossi C, Mazzanti L, Torrente I, Marino B, Digilio MC, Zampino G, Ackerman MJ, Dallapiccola B, Tartaglia M, Gelb BD. Gain-of-function RAF1 mutations cause Noonan and LEOPARD syndromes with hypertrophic cardiomyopathy. Nat Genet. 2007 Aug;39(8):1007-12. Epub 2007 Jul 1. PMID:17603483 doi:10.1038/ng2073
- ↑ Dubois T, Rommel C, Howell S, Steinhussen U, Soneji Y, Morrice N, Moelling K, Aitken A. 14-3-3 is phosphorylated by casein kinase I on residue 233. Phosphorylation at this site in vivo regulates Raf/14-3-3 interaction. J Biol Chem. 1997 Nov 14;272(46):28882-8. PMID:9360956
- ↑ Zheng W, Zhang Z, Ganguly S, Weller JL, Klein DC, Cole PA. Cellular stabilization of the melatonin rhythm enzyme induced by nonhydrolyzable phosphonate incorporation. Nat Struct Biol. 2003 Dec;10(12):1054-7. Epub 2003 Oct 26. PMID:14578935 doi:10.1038/nsb1005
- ↑ Tsuruta F, Sunayama J, Mori Y, Hattori S, Shimizu S, Tsujimoto Y, Yoshioka K, Masuyama N, Gotoh Y. JNK promotes Bax translocation to mitochondria through phosphorylation of 14-3-3 proteins. EMBO J. 2004 Apr 21;23(8):1889-99. Epub 2004 Apr 8. PMID:15071501 doi:10.1038/sj.emboj.7600194
- ↑ Ganguly S, Weller JL, Ho A, Chemineau P, Malpaux B, Klein DC. Melatonin synthesis: 14-3-3-dependent activation and inhibition of arylalkylamine N-acetyltransferase mediated by phosphoserine-205. Proc Natl Acad Sci U S A. 2005 Jan 25;102(4):1222-7. Epub 2005 Jan 11. PMID:15644438 doi:0406871102
- ↑ Gu YM, Jin YH, Choi JK, Baek KH, Yeo CY, Lee KY. Protein kinase A phosphorylates and regulates dimerization of 14-3-3 epsilon. FEBS Lett. 2006 Jan 9;580(1):305-10. Epub 2005 Dec 19. PMID:16376338 doi:S0014-5793(05)01485-7
- ↑ Dubois T, Rommel C, Howell S, Steinhussen U, Soneji Y, Morrice N, Moelling K, Aitken A. 14-3-3 is phosphorylated by casein kinase I on residue 233. Phosphorylation at this site in vivo regulates Raf/14-3-3 interaction. J Biol Chem. 1997 Nov 14;272(46):28882-8. PMID:9360956
- ↑ Chen J, Fujii K, Zhang L, Roberts T, Fu H. Raf-1 promotes cell survival by antagonizing apoptosis signal-regulating kinase 1 through a MEK-ERK independent mechanism. Proc Natl Acad Sci U S A. 2001 Jul 3;98(14):7783-8. Epub 2001 Jun 26. PMID:11427728 doi:10.1073/pnas.141224398
- ↑ Broustas CG, Grammatikakis N, Eto M, Dent P, Brautigan DL, Kasid U. Phosphorylation of the myosin-binding subunit of myosin phosphatase by Raf-1 and inhibition of phosphatase activity. J Biol Chem. 2002 Jan 25;277(4):3053-9. Epub 2001 Nov 21. PMID:11719507 doi:10.1074/jbc.M106343200
- ↑ Ding Q, Gros R, Gray ID, Taussig R, Ferguson SS, Feldman RD. Raf kinase activation of adenylyl cyclases: isoform-selective regulation. Mol Pharmacol. 2004 Oct;66(4):921-8. PMID:15385642 doi:10.1124/mol.66.4.
- ↑ O'Neill E, Rushworth L, Baccarini M, Kolch W. Role of the kinase MST2 in suppression of apoptosis by the proto-oncogene product Raf-1. Science. 2004 Dec 24;306(5705):2267-70. PMID:15618521 doi:10.1126/science.1103233
- ↑ Jin S, Zhuo Y, Guo W, Field J. p21-activated Kinase 1 (Pak1)-dependent phosphorylation of Raf-1 regulates its mitochondrial localization, phosphorylation of BAD, and Bcl-2 association. J Biol Chem. 2005 Jul 1;280(26):24698-705. Epub 2005 Apr 22. PMID:15849194 doi:10.1074/jbc.M413374200
- ↑ Wang Z, Wade P, Mandell KJ, Akyildiz A, Parkos CA, Mrsny RJ, Nusrat A. Raf 1 represses expression of the tight junction protein occludin via activation of the zinc-finger transcription factor slug. Oncogene. 2007 Feb 22;26(8):1222-30. Epub 2006 Aug 21. PMID:16924233 doi:10.1038/sj.onc.1209902
- ↑ Molzan M, Ottmann C. Synergistic Binding of the Phosphorylated S233- and S259-Binding Sites of C-RAF to One 14-3-3zeta Dimer. J Mol Biol. 2012 Aug 24. PMID:22922483 doi:10.1016/j.jmb.2012.08.009
|
