Engel K, Plath K, Gaestel M
Max-Delbrück-Center of Molecular Medicine, Berlin, Germany.
FEBS Lett. 1993 Dec 20;336(1):143-7. doi: 10.1016/0014-5793(93)81628-d.
The protein sequence of MAP kinase-activated protein kinase 2 (MAPKAP kinase 2) deduced from mouse cDNA sequence reveals structural features of the enzyme, which could be of importance for its function: a proline-rich SH3-binding domain N-terminal to the catalytic region, a MAP kinase phosphorylation site and a bipartite nuclear targeting sequence located C-terminal to the catalytic region. The catalytic domain itself has the strongest homology to calcium/calmodulin-dependent protein kinase II. Northern blot analysis demonstrates a 3.5 kb MAPKAP kinase 2 transcript which is ubiquitously expressed and, hence, co-expressed with the mRNA of the recently identified substrate Hsp25 in all tissues analysed. However, the functional consequences of the nuclear targeting sequence present in MAPKAP kinase 2 suggest the existence of further substrates for the enzyme in the nucleus.
从小鼠cDNA序列推导出来的丝裂原活化蛋白激酶激活的蛋白激酶2（MAPKAP激酶2）的蛋白质序列揭示了该酶的结构特征，这可能对其功能具有重要意义：在催化区域N端有一个富含脯氨酸的SH3结合结构域，一个丝裂原活化蛋白激酶磷酸化位点，以及一个位于催化区域C端的双分型核靶向序列。催化结构域本身与钙/钙调蛋白依赖性蛋白激酶II具有最强的同源性。Northern印迹分析显示有一个3.5 kb的MAPKAP激酶2转录本，它在所有组织中广泛表达，因此在所有分析的组织中都与最近鉴定出的底物Hsp25的mRNA共表达。然而，MAPKAP激酶2中存在的核靶向序列的功能后果表明该酶在细胞核中存在其他底物。
