Larochelle S, Suter B
Department of Biology, McGill University, Montreal, Québec, Canada.
Gene. 1995 Oct 3;163(2):209-14. doi: 10.1016/0378-1119(95)00279-f.
Recently, a mammalian kinase cascade was discovered that is triggered by stress and heat shock, and leads to the stimulation of mitogen-activated protein kinase (MAPK)-activated protein kinase-2 (MAPKAPK-2). Surprisingly, this process turns out to be independent of the classical MAPK. The stress-induced activation of MAPKAPK-2, in turn, results in the phosphorylation of small heat-shock proteins (Hsp). We have isolated a Drosophila melanogaster (Dm) cDNA encoding a polypeptide that has extensive sequence similarity to the mammalian MAPKAPK-2. As in mammalian MAPKAPK-2, the Dm MAPKAPK-2 possesses a MAPK phosphorylation site and a nuclear targeting sequence located C-terminal to the catalytic domain. However, in contrast to its mammalian counterpart, it lacks the Pro-rich N-terminal region proposed to form Src-homology domain 3 (SH3) binding domains. A 2.4-kb MAPKAPK-2 message is expressed throughout development, while two shorter transcripts of 2.3 and 1.8 kb appear to be specifically expressed in the germline. The 1.8-kb transcript results from the usage of an atypical germline-specific polyadenylation signal (AATATA) located early within the 3' untranslated region. Dm MAPKAPK-2 is located at cytological position 5D in the Dm genome.
最近，发现了一种哺乳动物激酶级联反应，它由应激和热休克触发，并导致丝裂原活化蛋白激酶（MAPK）激活的蛋白激酶-2（MAPKAPK-2）的激活。令人惊讶的是，这个过程与经典的MAPK无关。应激诱导的MAPKAPK-2激活反过来导致小热休克蛋白（Hsp）的磷酸化。我们分离出了一种果蝇（Dm）cDNA，其编码的多肽与哺乳动物MAPKAPK-2具有广泛的序列相似性。与哺乳动物MAPKAPK-2一样，Dm MAPKAPK-2具有一个MAPK磷酸化位点和一个位于催化结构域C末端的核靶向序列。然而，与它的哺乳动物对应物不同，它缺乏被认为形成Src同源结构域3（SH3）结合结构域的富含脯氨酸的N末端区域。一个2.4kb的MAPKAPK-2信使RNA在整个发育过程中表达，而两个较短的2.3kb和1.8kb转录本似乎在生殖系中特异性表达。1.8kb的转录本是由于使用了位于3'非翻译区早期的非典型生殖系特异性聚腺苷酸化信号（AATATA）。Dm MAPKAPK-2位于Dm基因组的细胞学位置5D处。
