按区室划分的Gα(h)（转谷氨酰胺酶II）的独特特征：GTP酶和转谷氨酰胺酶活性。

Distinct characteristic of Galpha(h) (transglutaminase II) by compartment: GTPase and transglutaminase activities.

作者信息

Park H, Park E S, Lee H S, Yun H Y, Kwon N S, Baek K J

机构信息

Institute of Medical Science, Department of Biochemistry, College of Medicine, Chung-Ang University, 221 Heuksuk-Dong, Dongjak-Ku, Seoul, 156-756, Republic of Korea.

出版信息

Biochem Biophys Res Commun. 2001 Jun 8;284(2):496-500. doi: 10.1006/bbrc.2001.4997.

DOI:10.1006/bbrc.2001.4997

PMID:11394908

Abstract

Galpha(h) (transglutaminase II) is a bifunctional enzyme possessing transglutaminase and GTPase activities. To better understand the factors affecting these two functions of Galpha(h), we have examined the characteristics of purified Galpha(h) from membrane and cytosol. GTP binding activity of mouse heart Galpha(h) was higher in membrane than that from cytosol. Furthermore, phospholipase C-delta1 (PLC-delta1) activity and coimmunoprecipitation of Galpha(h)-coupled PLC-delta1 in the alpha(1)-adrenoceptor-Galpha(h)-PLC-delta1 complex preparations were increased by phenylephrine in the presence of membranous Galpha(h). On the other hand, transglutaminase activity of cytosolic Galpha(h) was higher than that from membrane Galpha(h). These results demonstrate that bifunctions of Galpha(h) are regulated by its localization that can reflect the cellular functions of Galpha(h).

摘要

Gα(h)（转谷氨酰胺酶II）是一种具有转谷氨酰胺酶和GTP酶活性的双功能酶。为了更好地理解影响Gα(h)这两种功能的因素，我们研究了从膜和胞质溶胶中纯化得到的Gα(h)的特性。小鼠心脏Gα(h)的GTP结合活性在膜中高于胞质溶胶中的。此外，在存在膜性Gα(h)的情况下，苯肾上腺素可增加α(1)-肾上腺素能受体-Gα(h)-磷脂酶C-δ1（PLC-δ1）复合物制剂中Gα(h)偶联的PLC-δ1的活性和共免疫沉淀。另一方面，胞质溶胶Gα(h)的转谷氨酰胺酶活性高于膜Gα(h)的。这些结果表明，Gα(h)的双功能受其定位调节，而这种定位能够反映Gα(h)的细胞功能。