Hi Justin,

Since GPCRs are polytopic a-helical transmembrane proteins, it is very
likely that (1) insertion into the membrane is primarily performed by the
Sec61 complex AKA translocon and (2) targeting to the membrane would be
controlled by the signal recongition particle and its receptor. the latter
implies that a N-terminal signal sequence (that may very well be the first
TM of a GPCR) would control the insertion process. Does your favorite GPCR
have a predicetd  signal sequence?
Sec61 in theory contributes to signal sequence orientation according to the
positive-inside end rule....but as for any rule they are exceptions.

there is a set of excellent papers dissecting this mechanism by

Skach WR NSMB (2009) 16:6 606-12 (review)
Pitonzo & Skach Mol Biol Cell (2009) 20(2) 685-698 (article)
Sadlish H & Skach NSMB (2005) 12(10) 870-878 (article)
Sadlish and Skach J Membrane Biol 202 115-126 (2004) (review)

You may also want to look in the work of the group of Art Johnson (paper by
Woolhead et al)

describing the insertion process of aquaporin by the sec61 complex. they are
polytopic a-helical membrane proteins and you may want to look into these
articles since they dissect the process of TM insertion, orientation and
protein maturation quite well.

Hope this helps,

Best regards

Pascal F. Egea, PhD
Assistant Professor
UCLA, David Geffen School of Medicine
Department of Biological Chemistry
314 Biomedical Sciences Research Building
office (310)-983-3515
lab      (310)-983-3516
email     pe...@mednet.ucla.edu

Reply via email to