PHOSPHORYLATION OF UBIQUITIN-ACTIVATING ENZYME IN CULTURED-CELLS

被引：17

作者：

COOK, JC ^{[1
]}

CHOCK, PB ^{[1
]}

机构：

[1] NHLBI,BIOCHEM LAB,METAB REGULAT SECT,BETHESDA,MD 20892

来源：

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA | 1995年 / 92卷 / 08期

关键词：

D O I：

10.1073/pnas.92.8.3454

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Ubiquitin-activating enzyme, E1, is the first enzyme in the pathway leading: to formation of ubiquitin-protein conjugates. E1 exists as two isoforms in human cells which are separable by electrophoresis. These isoforms migrate with apparent molecular sizes of 110 kDa and 117 kDa in SDS/polyacrylamide gels. Immunoprecipitiation of E1 from lysates of HeLa cells metabolically labeled with [P-32]phosphate indicated the presence of a phosphorylated form of E1 which migrates at 117 kDa. Phospho amino acid analysis identified serine as the phosphorylated residue in E1. Phosphorylated E1 was also detected in normal and transformed cells from another human cell line. Phosphatase-catalyzed dephosphorylation of E1 in vitro did not eliminate the 117-kDa E1 isoform detected by Coomassie staining after SDS/polyacrylamide gel electrophoresis, thereby demonstrating that phosphorylation is not the sole structural feature differentiating the isoforms of E1. These observations suggest new hypotheses concerning mechanisms of metabolic regulation of the ubiquitin conjugation pathway.

引用

页码：3454 / 3457

页数：4

共 26 条

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