Sánchez C, Díaz-Nido J, Avila J
Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain.
Biochem J. 1995 Mar 1;306 ( Pt 2)(Pt 2):481-7. doi: 10.1042/bj3060481.
Microtubule-associated protein 2 (MAP2) is an in vitro substrate for MAP kinase. Part of the phosphorylation occurs at the C-terminal microtubule-binding domain of the molecule which contains a cluster of putative consensus sites for MAP kinase on a proline-rich region. A peptide with the sequence RTPGTPG-TPSY, located at this region of the molecule, is efficiently phosphorylated by MAP kinase in vitro. An antibody (972) raised against this non-phosphorylated peptide has been used to test for in vivo phosphorylation at the proline-rich domain of the MAP2 molecule. The reaction of purified MAP2 with antibody 972 diminishes after in vitro phosphorylation by MAP kinase and is enhanced after in vitro dephosphorylation by alkaline phosphatase. A fraction of brain MAP2 isolated by iron-chelation affinity chromatography appears to be phosphorylated in vivo at the site recognized by antibody 972. There is some variation in the phosphorylation of MAP2 at the proline-rich region throughout rat brain development. MAP2C is more highly phosphorylated in the developing rat brain, whereas high-molecular-mass MAP2 is more extensively phosphorylated in the adult rat brain.
微管相关蛋白2（MAP2）是丝裂原活化蛋白激酶（MAP激酶）的一种体外底物。部分磷酸化发生在该分子的C末端微管结合结构域，此结构域在富含脯氨酸的区域含有一簇推测的MAP激酶共有位点。位于该分子此区域的序列为RTPGTPG - TPSY的肽段在体外能被MAP激酶有效磷酸化。一种针对这种未磷酸化肽段产生的抗体（972）已被用于检测MAP2分子富含脯氨酸结构域的体内磷酸化情况。纯化的MAP2与抗体972的反应在经MAP激酶体外磷酸化后减弱，而在经碱性磷酸酶体外去磷酸化后增强。通过铁螯合亲和层析分离得到的一部分脑MAP2似乎在体内抗体972识别的位点发生了磷酸化。在大鼠脑发育过程中，MAP2在富含脯氨酸区域的磷酸化存在一些差异。MAP2C在发育中的大鼠脑中磷酸化程度更高，而高分子量的MAP2在成年大鼠脑中磷酸化更广泛。
