‘Piggy-Back’ Transport of Xenopus Hyaluronan Synthase (XHAS1) via the Secretory Pathway to the Plasma Membrane
‘Piggy-Back’ Transport of Xenopus Hyaluronan Synthase (XHAS1) via the Secretory Pathway to the Plasma Membrane
复制标题
非洲爪蟾透明质酸合酶 (XHAS1) 通过分泌途径“搭载”运输至质膜
DOI：
10.1515/bc.2003.019
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Lepperdinger
中科院分区：
文献类型：
--
作者：
J. Müllegger;A. Rustom;G. Kreil;H. Gerdes;G. Lepperdinger
Abstract Hyaluronan is the sole glycosaminoglycan whose biosynthesis takes place directly at the plasma membrane. The mechanism by which hyaluronan synthase (HAS) becomes inserted there, as well as the question of how the enzyme discriminates between particular membrane species in polarized cells, are largely unknown. In vitro translation of HAS suggested that the nascent protein becomes stabilized in the presence of microsomal membranes, but would not insert spontaneously into membranes after being translated in the absence of those. We therefore monitored the membrane attachment of enzymatically active fusion proteins consisting of Xenopus HAS1 and green fluorescent protein shortly after de novo synthesis in Vero cells. Our data strongly suggest that HAS proteins are directly translated on the ER membrane without exhibiting an N-terminal signal sequence. From there the inactive protein is transferred to the plasma membrane via the secretory pathway. For unknown reasons, HAS inserted into membranes other than the plasma membrane remains inactive.
