Dernayka Layal, Rauch Nora, Jarboui Mohamed-Ali, Zebisch Armin, Texier Yves, Horn Nicola, Romano David, Gloeckner Christian Johannes, Kriegsheim Alex von, Ueffing Marius, Kolch Walter, Boldt Karsten
Medical Proteome Center, Division for Experimental Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany.
Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
Cell Signal. 2016 Sep;28(9):1432-1439. doi: 10.1016/j.cellsig.2016.06.016. Epub 2016 Jun 21.
The BRAF proto-oncogene serine/threonine-protein kinase, known as BRAF, belongs to the RAF kinase family. It regulates the MAPK/ERK signalling pathway affecting several cellular processes such as growth, survival, differentiation, and cellular transformation. BRAF is mutated in ~8% of all human cancers with the V600E mutation constituting ~90% of mutations. Here, we have used quantitative mass spectrometry to map and compare phosphorylation site patterns between BRAF and BRAF V600E. We identified sites that are shared as well as several quantitative differences in phosphorylation abundance. The highest difference is phosphorylation of S614 in the activation loop which is ~5fold enhanced in BRAF V600E. Mutation of S614 increases the kinase activity of both BRAF and BRAF V600E and the transforming ability of BRAF V600E. The phosphorylation of S614 is mitogen inducible and the result of autophosphorylation. These data suggest that phosphorylation at this site is inhibitory, and part of the physiological shut-down mechanism of BRAF signalling.
BRAF原癌基因丝氨酸/苏氨酸蛋白激酶，简称为BRAF，属于RAF激酶家族。它调控MAPK/ERK信号通路，影响多种细胞过程，如生长、存活、分化和细胞转化。在所有人类癌症中，约8%的病例存在BRAF突变，其中V600E突变约占所有突变的90%。在此，我们利用定量质谱技术绘制并比较了BRAF与BRAF V600E之间的磷酸化位点图谱。我们鉴定出了共有的位点以及磷酸化丰度方面的一些定量差异。差异最大的是激活环中S614的磷酸化，在BRAF V600E中增强了约5倍。S614突变会增加BRAF和BRAF V600E的激酶活性以及BRAF V600E的转化能力。S614的磷酸化是有丝分裂诱导的，并且是自磷酸化的结果。这些数据表明，该位点的磷酸化具有抑制作用，是BRAF信号传导生理关闭机制的一部分。
