Maucuer A, Le Caer J P, Manceau V, Sobel A
INSERM U440, Institut du Fer à Moulin, Paris, France.
Eur J Biochem. 2000 Jul;267(14):4456-64. doi: 10.1046/j.1432-1327.2000.01493.x.
We present here a first appraisal of the phosphorylation site specificity of KIS (for 'kinase interacting with stathmin'), a novel mammalian kinase that has the unique feature among kinases to possess an RNP type RNA-recognition motif (RRM). In vitro kinase assays using various standard substrates revealed that KIS has a narrow specificity, with myelin basic protein (MBP) and synapsin I being the best in vitro substrates among those tested. Mass spectrometry and peptide sequencing allowed us to identify serine 164 of MBP as the unique site phosphorylated by KIS. Phosphorylation of synthetic peptides indicated the importance of the proline residue at position +1. We also identified a tryptic peptide of synapsin I phosphorylated by KIS and containing a phosphorylatable Ser-Pro motif. Altogether, our results suggest that KIS preferentially phosphorylates proline directed residues but has a specificity different from that of MAP kinases and cdks.
我们在此首次评估KIS（“与微管相关蛋白2相互作用的激酶”）的磷酸化位点特异性，KIS是一种新型哺乳动物激酶，在激酶中具有独特特征，即拥有一个RNP型RNA识别基序（RRM）。使用各种标准底物进行的体外激酶测定表明，KIS具有狭窄的特异性，在测试的底物中，髓鞘碱性蛋白（MBP）和突触素I是最佳的体外底物。质谱分析和肽测序使我们能够确定MBP的丝氨酸164是被KIS磷酸化的唯一位点。合成肽的磷酸化表明了+1位脯氨酸残基的重要性。我们还鉴定出了突触素I的一个经KIS磷酸化且含有可磷酸化的Ser-Pro基序的胰蛋白酶肽段。总之，我们的结果表明，KIS优先磷酸化脯氨酸导向的残基，但具有与丝裂原活化蛋白激酶和周期蛋白依赖性激酶不同的特异性。
