Bianchi M W, Guivarc'h D, Thomas M, Woodgett J R, Kreis M
Centre de Recherches sur les Plantes URA 1128, Université de Paris-Sud, Orsay, France.
Mol Gen Genet. 1994 Feb;242(3):337-45. doi: 10.1007/BF00280424.
The conservation in evolution of fundamental signal transduction modules offers a means of isolating genes likely to be involved in plant development. We have amplified by PCR Arabidopsis cDNA and genomic sequences related to the product of the shaggy/zeste-white 3 (sgg) segment polarity gene of Drosophila. This regulatory protein is functionally homologous to glycogen synthase kinase-3 in mammals (GSK-3), which regulates, among others, the DNA-binding activity of the c-jun/AP1 transcription factor. Analysis of PCR products led to the identification of five genes; for two of which, corresponding full-length cDNAs, ASK-alpha and gamma (for Arabidopsis shaggy-related protein kinase), were characterized. The encoded proteins were 70% identical to GSK-3 and sgg over the protein kinase catalytic domain and, after production in Escherichia coli, autophosphorylated mainly on threonine and serine residues, but phosphotyrosine was also detected. ASK-alpha and ASK-gamma also phosphorylated phosphatase inhibitor-2 and myelin basic protein, on threonine and serine, respectively. The high conservation of the protein kinases of GSK-3 family, and their action at the transcriptional level, suggest that the ASK proteins have important functions in higher plants.
基本信号转导模块在进化过程中的保守性为分离可能参与植物发育的基因提供了一种方法。我们通过PCR扩增了与果蝇的粗短/小体白色3(sgg)节段极性基因产物相关的拟南芥cDNA和基因组序列。这种调节蛋白在功能上与哺乳动物中的糖原合酶激酶-3(GSK-3)同源,GSK-3除其他外还调节c-jun/AP1转录因子的DNA结合活性。对PCR产物的分析导致鉴定出五个基因;其中两个基因的相应全长cDNA,即ASK-α和γ(用于拟南芥粗短相关蛋白激酶),得到了表征。编码的蛋白质在蛋白激酶催化结构域上与GSK-3和sgg有70%的同一性,在大肠杆菌中产生后,主要在苏氨酸和丝氨酸残基上进行自磷酸化,但也检测到了磷酸酪氨酸。ASK-α和ASK-γ还分别在苏氨酸和丝氨酸上磷酸化磷酸酶抑制剂-2和髓鞘碱性蛋白。GSK-3家族蛋白激酶的高度保守性及其在转录水平上的作用表明,ASK蛋白在高等植物中具有重要功能。