The Drosophila melanogaster homolog of the mammalian MAPK-activated protein kinase-2 (MAPKAPK-2) lacks a proline-rich N-terminus.
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.
Larochelle
S
S
Department of Biology, McGill University, Montreal, Québec, Canada.
Suter
B
B
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004331:Drosophila melanogaster / Q000235:genetics*; D006360:Heat-Shock Proteins / Q000235:genetics*; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D011392:Proline / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics*; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D017421:Sequence Analysis
D006360:Heat-Shock Proteins; D011392:Proline; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D048370:MAP Kinase Kinase 2; D020929:Mitogen-Activated Protein Kinase Kinases