Tail-anchored and Signal-anchored Proteins Utilize Overlapping Pathways during Membrane Insertion

Benjamin M. Abell, Martin Jung, Jason D. Oliver, Bruce C. Knight, Jens Tyedmers, Richard Zimmermann, Stephen High
2002 Journal of Biological Chemistry  
Tail-anchored proteins are a distinct class of membrane proteins that are characterized by a C-terminal membrane insertion sequence and a capacity for posttranslational integration. Although it is now clear that tail-anchored proteins are inserted into the membrane at the endoplasmic reticulum (ER), the molecular basis for their integration is poorly understood. We have used a cross-linking approach to identify ER components that may be involved in the membrane insertion of tailanchored
more » ... ailanchored proteins. We find that several newly synthesized tail-anchored proteins are transiently associated with a defined subset of cellular components. Among these, we identify several ER proteins, including subunits of the Sec61 translocon, Sec62p, Sec63p, and the 25-kDa subunit of the signal peptidase complex. When we analyze the cotranslational membrane insertion of a comparable signal-anchored protein we find the nascent polypeptide associated with a similar set of ER components. We conclude that the pathways for the integration of tail-anchored and signal-anchored membrane proteins at the ER exhibit a substantial degree of overlap, and we propose that this reflects similarities between co-and post-translational membrane insertion.
doi:10.1074/jbc.m209968200 pmid:12464599 fatcat:jp5csw2mvvdr3fq3cxnfarlgna