Cotranslational protein integration into the ER membrane is mediated by the binding of nascent chains to translocon proteins

被引：85

作者：

McCormick, PJ

Miao, YW

Shao, YL

Lin, JL

Johnson, AE ^{[1
]}

机构：

[1] Texas A&M Univ, Dept Biochem & Biophys, College Stn, TX 77843 USA

[2] Texas A&M Univ, Dept Med Biochem & Genet, Hlth Sci Ctr, College Stn, TX 77843 USA

[3] Univ Oklahoma, Hlth Sci Ctr, Dept Biochem & Mol Biol, Oklahoma City, OK 73104 USA

[4] Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA

来源：

MOLECULAR CELL | 2003年 / 12卷 / 02期

关键词：

D O I：

10.1016/S1097-2765(03)00304-6

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

During cotranslational protein integration into the ER membrane, each transmembrane (TM) segment moves laterally through the translocon to reach the lipid bilayer. Photocrosslinking studies reveal that a particular surface of each nascent chain TM alpha helix and signal-anchor sequence always faces Sec61alpha in the translocon. This nonrandom and TM sequence-dependent positioning reveals that each TM segment makes specific contacts with Sec61alpha and is retained at a fixed location within the translocon, observations that are best explained by the binding of each TM sequence to a translocon protein(s). Since TM sequence hydrophobicity does not correlate with its rate of release from the translocon, nascent chain movement through the translocon appears to be mediated primarily by protein-protein interactions rather than hydrophobic nascent chain-phospholipid interactions.

引用

页码：329 / 341

页数：13

共 21 条

[11] Both lumenal and cytosolic gating of the aqueous ER translocon pore are regulated from inside the ribosome during membrane protein integration [J].