6so5

Homo sapiens WRB/CAML heterotetramer in complex with a TRC40 dimerHomo sapiens WRB/CAML heterotetramer in complex with a TRC40 dimer

Structural highlights

6so5 is a 6 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 4.2Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

GET3_HUMAN The disease is caused by variants affecting the gene represented in this entry.

Function

GET3_HUMAN ATPase required for the post-translational delivery of tail-anchored (TA) proteins to the endoplasmic reticulum. Recognizes and selectively binds the transmembrane domain of TA proteins in the cytosol. This complex then targets to the endoplasmic reticulum by membrane-bound receptors GET1/WRB and CAMLG/GET2, where the tail-anchored protein is released for insertion. This process is regulated by ATP binding and hydrolysis. ATP binding drives the homodimer towards the closed dimer state, facilitating recognition of newly synthesized TA membrane proteins. ATP hydrolysis is required for insertion. Subsequently, the homodimer reverts towards the open dimer state, lowering its affinity for the GET1-CAMLG receptor, and returning it to the cytosol to initiate a new round of targeting. May be involved in insulin signaling.[HAMAP-Rule:MF_03112]^[1] ^[2] ^[3] ^[4] ^[5]

Publication Abstract from PubMed

Membrane protein biogenesis faces the challenge of chaperoning hydrophobic transmembrane helices for faithful membrane insertion. The guided entry of tail-anchored proteins (GET) pathway targets and inserts tail-anchored (TA) proteins into the endoplasmic reticulum (ER) membrane with an insertase (yeast Get1/Get2 or mammalian WRB/CAML) that captures the TA from a cytoplasmic chaperone (Get3 or TRC40, respectively). Here, we present cryo-electron microscopy reconstructions, native mass spectrometry, and structure-based mutagenesis of human WRB/CAML/TRC40 and yeast Get1/Get2/Get3 complexes. Get3 binding to the membrane insertase supports heterotetramer formation, and phosphatidylinositol binding at the heterotetramer interface stabilizes the insertase for efficient TA insertion in vivo. We identify a Get2/CAML cytoplasmic helix that forms a "gating" interaction with Get3/TRC40 important for TA insertion. Structural homology with YidC and the ER membrane protein complex (EMC) implicates an evolutionarily conserved insertion mechanism for divergent substrates utilizing a hydrophilic groove. Thus, we provide a detailed structural and mechanistic framework to understand TA membrane insertion.

Structural Basis of Tail-Anchored Membrane Protein Biogenesis by the GET Insertase Complex.,McDowell MA, Heimes M, Fiorentino F, Mehmood S, Farkas A, Coy-Vergara J, Wu D, Bolla JR, Schmid V, Heinze R, Wild K, Flemming D, Pfeffer S, Schwappach B, Robinson CV, Sinning I Mol Cell. 2020 Oct 1;80(1):72-86.e7. doi: 10.1016/j.molcel.2020.08.012. Epub 2020, Sep 9. PMID:32910895^[6]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Stefanovic S, Hegde RS. Identification of a targeting factor for posttranslational membrane protein insertion into the ER. Cell. 2007 Mar 23;128(6):1147-59. PMID:17382883 doi:10.1016/j.cell.2007.01.036
↑ Favaloro V, Spasic M, Schwappach B, Dobberstein B. Distinct targeting pathways for the membrane insertion of tail-anchored (TA) proteins. J Cell Sci. 2008 Jun 1;121(11):1832-40. PMID:18477612 doi:10.1242/jcs.020321
↑ Yamamoto Y, Sakisaka T. Molecular machinery for insertion of tail-anchored membrane proteins into the endoplasmic reticulum membrane in mammalian cells. Mol Cell. 2012 Nov 9;48(3):387-97. PMID:23041287 doi:10.1016/j.molcel.2012.08.028
↑ Mock J, Chartron JW, Zaslaver M, Xu Y, Ye Y, Clemons WM Jr. Bag6 complex contains a minimal tail-anchor-targeting module and a mock BAG domain. Proc Natl Acad Sci U S A. 2014 Dec 22. pii: 201402745. PMID:25535373 doi:http://dx.doi.org/10.1073/pnas.1402745112
↑ Verhagen JMA, van den Born M, van der Linde HC, G J Nikkels P, Verdijk RM, Kivlen MH, van Unen LMA, Baas AF, Ter Heide H, van Osch-Gevers L, Hoogeveen-Westerveld M, Herkert JC, Bertoli-Avella AM, van Slegtenhorst MA, Wessels MW, Verheijen FW, Hassel D, Hofstra RMW, Hegde RS, van Hasselt PM, van Ham TJ, van de Laar IMBH. Biallelic Variants in ASNA1, Encoding a Cytosolic Targeting Factor of Tail-Anchored Proteins, Cause Rapidly Progressive Pediatric Cardiomyopathy. Circ Genom Precis Med. 2019 Sep;12(9):397-406. PMID:31461301 doi:10.1161/CIRCGEN.119.002507
↑ McDowell MA, Heimes M, Fiorentino F, Mehmood S, Farkas A, Coy-Vergara J, Wu D, Bolla JR, Schmid V, Heinze R, Wild K, Flemming D, Pfeffer S, Schwappach B, Robinson CV, Sinning I. Structural Basis of Tail-Anchored Membrane Protein Biogenesis by the GET Insertase Complex. Mol Cell. 2020 Oct 1;80(1):72-86.e7. doi: 10.1016/j.molcel.2020.08.012. Epub 2020, Sep 9. PMID:32910895 doi:http://dx.doi.org/10.1016/j.molcel.2020.08.012

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OCA

[1] Stefanovic S, Hegde RS. Identification of a targeting factor for posttranslational membrane protein insertion into the ER. Cell. 2007 Mar 23;128(6):1147-59. PMID:17382883 doi:10.1016/j.cell.2007.01.036

[2] Favaloro V, Spasic M, Schwappach B, Dobberstein B. Distinct targeting pathways for the membrane insertion of tail-anchored (TA) proteins. J Cell Sci. 2008 Jun 1;121(11):1832-40. PMID:18477612 doi:10.1242/jcs.020321

[3] Yamamoto Y, Sakisaka T. Molecular machinery for insertion of tail-anchored membrane proteins into the endoplasmic reticulum membrane in mammalian cells. Mol Cell. 2012 Nov 9;48(3):387-97. PMID:23041287 doi:10.1016/j.molcel.2012.08.028

[4] Mock J, Chartron JW, Zaslaver M, Xu Y, Ye Y, Clemons WM Jr. Bag6 complex contains a minimal tail-anchor-targeting module and a mock BAG domain. Proc Natl Acad Sci U S A. 2014 Dec 22. pii: 201402745. PMID:25535373 doi:http://dx.doi.org/10.1073/pnas.1402745112

[5] Verhagen JMA, van den Born M, van der Linde HC, G J Nikkels P, Verdijk RM, Kivlen MH, van Unen LMA, Baas AF, Ter Heide H, van Osch-Gevers L, Hoogeveen-Westerveld M, Herkert JC, Bertoli-Avella AM, van Slegtenhorst MA, Wessels MW, Verheijen FW, Hassel D, Hofstra RMW, Hegde RS, van Hasselt PM, van Ham TJ, van de Laar IMBH. Biallelic Variants in ASNA1, Encoding a Cytosolic Targeting Factor of Tail-Anchored Proteins, Cause Rapidly Progressive Pediatric Cardiomyopathy. Circ Genom Precis Med. 2019 Sep;12(9):397-406. PMID:31461301 doi:10.1161/CIRCGEN.119.002507

[6] McDowell MA, Heimes M, Fiorentino F, Mehmood S, Farkas A, Coy-Vergara J, Wu D, Bolla JR, Schmid V, Heinze R, Wild K, Flemming D, Pfeffer S, Schwappach B, Robinson CV, Sinning I. Structural Basis of Tail-Anchored Membrane Protein Biogenesis by the GET Insertase Complex. Mol Cell. 2020 Oct 1;80(1):72-86.e7. doi: 10.1016/j.molcel.2020.08.012. Epub 2020, Sep 9. PMID:32910895 doi:http://dx.doi.org/10.1016/j.molcel.2020.08.012

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