Wong K, Cantley L C
Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115.
J Biol Chem. 1994 Nov 18;269(46):28878-84.
Phosphatidylinositol (PtdIns) 4-kinase catalyzes the first committed step in the biosynthesis of phosphatidylinositol 4,5-bisphosphate. Here we report the first mammalian cDNA clone of a PtdIns 4-kinase (named PI4K alpha). The 2.6-kb cDNA encodes a protein of 854 amino acids that is highly homologous to the recently cloned yeast PtdIns 4-kinase STT4 and is also homologous to a second yeast PtdIns 4-kinase, PIK1. PI4K alpha has more distant sequence homology to the catalytic domains of mammalian and yeast PtdIns 3-kinases and to the yeast Tor family of proteins. It also has a region of similarity to pleckstrin homology domains and a potential ankyrin repeat. Cross-hybridizing messages were detected in all human tissues investigated. The enzymatic properties of the protein expressed in insect cells are characteristic of type II PtdIns 4-kinases (activated by detergent and inhibited by adenosine), and PI4K alpha is recognized by an antibody specific for type II PtdIns 4-kinases.
磷脂酰肌醇（PtdIns）4-激酶催化磷脂酰肌醇4,5-二磷酸生物合成中的首个关键步骤。在此，我们报道了首个哺乳动物PtdIns 4-激酶（命名为PI4Kα）的cDNA克隆。这个2.6kb的cDNA编码一个含854个氨基酸的蛋白质，它与最近克隆的酵母PtdIns 4-激酶STT4高度同源，同时也与另一个酵母PtdIns 4-激酶PIK1同源。PI4Kα与哺乳动物和酵母PtdIns 3-激酶的催化结构域以及酵母Tor蛋白家族具有较远的序列同源性。它还有一个与普列克底物蛋白同源结构域相似的区域以及一个潜在的锚蛋白重复序列。在所研究的所有人类组织中均检测到交叉杂交信号。在昆虫细胞中表达的该蛋白的酶学特性属于II型PtdIns 4-激酶（被去污剂激活且被腺苷抑制），并且PI4Kα能被针对II型PtdIns 4-激酶的特异性抗体识别。
