Kulman J D, Harris J E, Haldeman B A, Davie E W
Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.
Proc Natl Acad Sci U S A. 1997 Aug 19;94(17):9058-62. doi: 10.1073/pnas.94.17.9058.
Two human cDNAs that encode novel vitamin K-dependent proteins have been cloned and sequenced. The predicted amino acid sequences suggest that both are single-pass transmembrane proteins with amino-terminal gamma-carboxyglutamic acid-containing domains preceded by the typical propeptide sequences required for posttranslational gamma-carboxylation of glutamic acid residues. The polypeptides, with deduced molecular masses of 23 and 17 kDa, are proline-rich within their putative cytoplasmic domains and contain several copies of the sequences PPXY and PXXP, motifs found in a variety of signaling and cytoskeletal proteins. Accordingly, these two proteins have been called proline-rich Gla proteins (PRGP1 and PRGP2). Unlike the gamma-carboxyglutamic acid domain-containing proteins of the blood coagulation cascade, the two PRGPs are expressed in a variety of extrahepatic tissues, with PRGP1 and PRGP2 most abundantly expressed in the spinal cord and thyroid, respectively, among those tissues tested. Thus, these observations suggest a novel physiological role for these two new members of the vitamin K-dependent family of proteins.
已克隆并测序了两个编码新型维生素K依赖性蛋白的人cDNA。预测的氨基酸序列表明，这两种蛋白都是单次跨膜蛋白，其氨基末端含有γ-羧基谷氨酸的结构域之前是谷氨酸残基翻译后γ-羧化所需的典型前肽序列。这两种多肽的推导分子量分别为23 kDa和17 kDa，在其假定的细胞质结构域中富含脯氨酸，并包含多个PPXY和PXXP序列拷贝，这些基序存在于多种信号蛋白和细胞骨架蛋白中。因此，这两种蛋白被称为富含脯氨酸的Gla蛋白（PRGP1和PRGP2）。与凝血级联反应中含γ-羧基谷氨酸结构域的蛋白不同，这两种PRGP在多种肝外组织中表达，在所测试的组织中，PRGP1和PRGP2分别在脊髓和甲状腺中表达最为丰富。因此，这些观察结果表明了维生素K依赖性蛋白家族这两个新成员的新生理作用。
