Urao T, Katagiri T, Mizoguchi T, Yamaguchi-Shinozaki K, Hayashida N, Shinozaki K
Laboratory of Plant Molecular Biology, Institute of Physical and Chemical Research (RIKEN), Tsukuba Life Science Center, Ibaraki, Japan.
Mol Gen Genet. 1994 Aug 15;244(4):331-40. doi: 10.1007/BF00286684.
Two cDNA clones, cATCDPK1 and cATCDPK2, encoding Ca(2+)-dependent, calmodulin-independent protein kinases (CDPK) were cloned from Arabidopsis thaliana and their nucleotide sequences were determined. Northern blot analysis indicated that the mRNAs corresponding to the ATCDPK1 and ATCDPK2 genes are rapidly induced by drought and high-salt stress but not by low-temperature stress or heat stress. Treatment of Arabidopsis plants with exogenous abscisic acid (ABA) had no effect on the induction of ATCDPK1 or ATCDPK2. These findings suggest that a change in the osmotic potential of the environment can serve as a trigger for the induction of ATCDPK1 and ATCDPK2. Putative proteins encoded by ATCDPK1 and ATCDPK2 which contain open reading frames of 1479 and 1488 bp, respectively, are designated ATCDPK1 and ATCDPK2 and show 52% identity at the amino acid sequence level. ATCDPK1 and ATCDPK2 exhibit significant similarity to a soybean CDPK (51% and 73%, respectively). Both proteins contain a catalytic domain that is typical of serine/threonine protein kinases and a regulatory domain that is homologous to the Ca(2+)-binding sites of calmodulin. Genomic Southern blot analysis suggests the existence of a few additional genes that are related to ATCDPK1 and ATCDPK2 in the Arabidopsis genome. The ATCDPK2 protein expressed in Escherichia coli was found to phosphorylate casein and myelin basic protein preferentially, relative to a histone substrate, and required Ca2+ for activation.
从拟南芥中克隆出了两个编码依赖Ca(2+)、不依赖钙调蛋白的蛋白激酶（CDPK）的cDNA克隆，即cATCDPK1和cATCDPK2，并测定了它们的核苷酸序列。Northern印迹分析表明，与ATCDPK1和ATCDPK2基因相对应的mRNA可被干旱和高盐胁迫快速诱导，但不受低温胁迫或热胁迫诱导。用外源脱落酸（ABA）处理拟南芥植株对ATCDPK1或ATCDPK2的诱导没有影响。这些发现表明，环境渗透势的变化可能是诱导ATCDPK1和ATCDPK2的触发因素。由ATCDPK1和ATCDPK2编码的推定蛋白分别包含1479和1488 bp的开放阅读框，被命名为ATCDPK1和ATCDPK2，在氨基酸序列水平上具有52%的同一性。ATCDPK1和ATCDPK2与一种大豆CDPK具有显著相似性（分别为51%和73%）。这两种蛋白都含有一个典型的丝氨酸/苏氨酸蛋白激酶催化结构域和一个与钙调蛋白的Ca(2+)结合位点同源的调节结构域。基因组Southern印迹分析表明，在拟南芥基因组中存在一些与ATCDPK1和ATCDPK2相关的其他基因。相对于组蛋白底物，在大肠杆菌中表达的ATCDPK2蛋白被发现优先磷酸化酪蛋白和髓鞘碱性蛋白，并且激活需要Ca2+。
