TY - JOUR
T1 - An alternative pathway for membrane protein biogenesis at the endoplasmic reticulum
AU - O'Keefe, Sarah
AU - Zong, Guanghui
AU - Duah, Kwabena Baffour
AU - Andrews, Lauren E.
AU - Shi, Wei Q.
AU - High, Stephen
N1 - Funding Information:
For gifting reagents, we thank Cornelia Wilson (CD3δ cDNA; Canterbury Christ Church University, Kent, UK), Martin Spiess (ASGR1 cDNA; University of Basel, Basel, Switzerland), Jeffrey Brodsky (ppαF cDNA; University of Pittsburgh, Pittsburgh, PA), Sven Lang and Richard Zimmermann (Sec61α and hSnd2 antisera; University of Saar-land, Homburg, Germany) and Martin Pool (SRα antisera; University of Manchester). We additionally thank Pawel Leznicki, Martin Pool and Lisa Swanton (University of Manchester, Manchester, UK) and Joen Luirink (Free University, Amsterdam, Netherlands) for critical feedback during manuscript preparation and revision. This work was supported by a Welcome Trust Investigator Award in Science 204957/Z/16/Z (S.H.) and an AREA grant 2R15GM116032-02A1 from the National Institute of General Medical Sciences of the National Institutes of Health (NIH) and a Ball State University (BSU) Provost Startup Award (W.Q.S.). L.E.A. is the recipient of BSU honors college research grants from 01/2020 to 12/2020.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/7/1
Y1 - 2021/7/1
N2 - The heterotrimeric Sec61 complex is a major site for the biogenesis of transmembrane proteins (TMPs), accepting nascent TMP precursors that are targeted to the endoplasmic reticulum (ER) by the signal recognition particle (SRP). Unlike most single-spanning membrane proteins, the integration of type III TMPs is completely resistant to small molecule inhibitors of the Sec61 translocon. Using siRNA-mediated depletion of specific ER components, in combination with the potent Sec61 inhibitor ipomoeassin F (Ipom-F), we show that type III TMPs utilise a distinct pathway for membrane integration at the ER. Hence, following SRP-mediated delivery to the ER, type III TMPs can uniquely access the membrane insertase activity of the ER membrane complex (EMC) via a mechanism that is facilitated by the Sec61 translocon. This alternative EMC-mediated insertion pathway allows type III TMPs to bypass the Ipom-F-mediated blockade of membrane integration that is seen with obligate Sec61 clients.
AB - The heterotrimeric Sec61 complex is a major site for the biogenesis of transmembrane proteins (TMPs), accepting nascent TMP precursors that are targeted to the endoplasmic reticulum (ER) by the signal recognition particle (SRP). Unlike most single-spanning membrane proteins, the integration of type III TMPs is completely resistant to small molecule inhibitors of the Sec61 translocon. Using siRNA-mediated depletion of specific ER components, in combination with the potent Sec61 inhibitor ipomoeassin F (Ipom-F), we show that type III TMPs utilise a distinct pathway for membrane integration at the ER. Hence, following SRP-mediated delivery to the ER, type III TMPs can uniquely access the membrane insertase activity of the ER membrane complex (EMC) via a mechanism that is facilitated by the Sec61 translocon. This alternative EMC-mediated insertion pathway allows type III TMPs to bypass the Ipom-F-mediated blockade of membrane integration that is seen with obligate Sec61 clients.
UR - http://www.scopus.com/inward/record.url?scp=85109192741&partnerID=8YFLogxK
U2 - 10.1038/s42003-021-02363-z
DO - 10.1038/s42003-021-02363-z
M3 - Article
SN - 2399-3642
VL - 4
JO - Communications Biology
JF - Communications Biology
IS - 1
M1 - 828
ER -