Structure of the Eukaryotic Protein O-mannosyltransferase Pmt1-Pmt2 Complex

Overview

Journal Nat Struct Mol Biol

Specialties Cell Biology
Molecular Biology

Date 2019 Jul 10

PMID 31285605

Citations 21

Authors

Lin Bai

Amanda Kovach

Qinglong You

Alanna Kenny

Huilin Li

Affiliations

Soon will be listed here.

Abstract

In eukaryotes, a nascent peptide entering the endoplasmic reticulum (ER) is scanned by two Sec61 translocon-associated large membrane machines for protein N-glycosylation and protein O-mannosylation, respectively. While the structure of the eight-protein oligosaccharyltransferase complex has been determined recently, the structures of mannosyltransferases of the PMT family, which are an integral part of ER protein homeostasis, are still unknown. Here we report cryo-EM structures of the Saccharomyces cerevisiae Pmt1-Pmt2 complex bound to a donor and an acceptor peptide at 3.2-Å resolution, showing that each subunit contains 11 transmembrane helices and a lumenal β-trefoil fold termed the MIR domain. The structures reveal the substrate recognition model and confirm an inverting mannosyl-transferring reaction mechanism by the enzyme complex. Furthermore, we found that the transmembrane domains of Pmt1 and Pmt2 share a structural fold with the catalytic subunits of oligosaccharyltransferases, confirming a previously proposed evolutionary relationship between protein O-mannosylation and protein N-glycosylation.

Citing Articles

Malformations of Core M3 on α-Dystroglycan Are the Leading Cause of Dystroglycanopathies.

Sharaf-Eldin W J Mol Neurosci. 2025; 75(1):28.

PMID: 39998573 PMC: 11861012. DOI: 10.1007/s12031-025-02320-z.

Differential substrate preferences IN ACTINOBACTERIAL protein O-MANNOSYLTRANSFERASES and alteration of protein-O-MANNOSYLATION by choice of secretion pathway.

Saxena H, Patel R, Kelly J, Wakarchuk W Glycobiology. 2024; 35(1).

PMID: 39673494 PMC: 11727336. DOI: 10.1093/glycob/cwae095.

Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans.

Kelly S, Duong N, Nothof J, Lowary T, Whitfield C Proc Natl Acad Sci U S A. 2024; 121(21):e2402554121.

PMID: 38748580 PMC: 11127046. DOI: 10.1073/pnas.2402554121.

Removal of pomt1 in zebrafish leads to loss of α-dystroglycan glycosylation and dystroglycanopathy phenotypes.

Karas B, Terez K, Mowla S, Battula N, Flannery K, Gural B Hum Mol Genet. 2024; 33(8):709-723.

PMID: 38272461 PMC: 11000664. DOI: 10.1093/hmg/ddae006.

Protein O-mannosylation: one sugar, several pathways, many functions.

Koff M, Monagas-Valentin P, Novikov B, Chandel I, Panin V Glycobiology. 2023; 33(11):911-926.

PMID: 37565810 PMC: 10859634. DOI: 10.1093/glycob/cwad067.

References

Balci B, Uyanik G, Dincer P, Gross C, Willer T, Talim B . An autosomal recessive limb girdle muscular dystrophy (LGMD2) with mild mental retardation is allelic to Walker-Warburg syndrome (WWS) caused by a mutation in the POMT1 gene. Neuromuscul Disord. 2005; 15(4):271-5. DOI: 10.1016/j.nmd.2005.01.013. View

Yanagisawa A, Bouchet C, Quijano-Roy S, Vuillaumier-Barrot S, Clarke N, Odent S . POMT2 intragenic deletions and splicing abnormalities causing congenital muscular dystrophy with mental retardation. Eur J Med Genet. 2009; 52(4):201-6. DOI: 10.1016/j.ejmg.2008.12.004. View

Chen C, Mei S, Zhu C, Ren Y, Kong X . [Analysis of POMT1 gene mutation in a pedigree affected with congenital muscular dystrophy]. Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2018; 35(1):78-80. DOI: 10.3760/cma.j.issn.1003-9406.2018.01.017. View

Emsley P, Lohkamp B, Scott W, Cowtan K . Features and development of Coot. Acta Crystallogr D Biol Crystallogr. 2010; 66(Pt 4):486-501. PMC: 2852313. DOI: 10.1107/S0907444910007493. View

Yanagisawa A, Bouchet C, van den Bergh P, Cuisset J, Viollet L, Leturcq F . New POMT2 mutations causing congenital muscular dystrophy: identification of a founder mutation. Neurology. 2007; 69(12):1254-60. DOI: 10.1212/01.wnl.0000268489.60809.c4. View

Chong Y, Ma L, Lo K, Lee C, Mak C, Kan A . Dystroglycanopathy with two novel POMT1 mutations in a Chinese boy with developmental delay and muscular dystrophy. Eur J Paediatr Neurol. 2014; 18(4):532-5. DOI: 10.1016/j.ejpn.2014.03.003. View

Tanner W . Protein O-glycosylation in Saccharomyces cerevisiae. Purification and characterization of the dolichyl-phosphate-D-mannose-protein O-D-mannosyltransferase. Eur J Biochem. 1991; 196(1):185-90. DOI: 10.1111/j.1432-1033.1991.tb15802.x. View

Bai L, Li H . Cryo-EM is uncovering the mechanism of eukaryotic protein N-glycosylation. FEBS J. 2018; 286(9):1638-1644. PMC: 6504584. DOI: 10.1111/febs.14705. View

Aebi M . N-linked protein glycosylation in the ER. Biochim Biophys Acta. 2013; 1833(11):2430-7. DOI: 10.1016/j.bbamcr.2013.04.001. View

10.

Lommel M, Schott A, Jank T, Hofmann V, Strahl S . A conserved acidic motif is crucial for enzymatic activity of protein O-mannosyltransferases. J Biol Chem. 2011; 286(46):39768-75. PMC: 3220539. DOI: 10.1074/jbc.M111.281196. View

11.

Zhang L, Ten Hagen K . O-Linked glycosylation in Drosophila melanogaster. Curr Opin Struct Biol. 2019; 56:139-145. PMC: 6656608. DOI: 10.1016/j.sbi.2019.01.014. View

12.

Immervoll T, Gentzsch M, Tanner W . PMT3 and PMT4, two new members of the protein-O-mannosyltransferase gene family of Saccharomyces cerevisiae. Yeast. 1995; 11(14):1345-51. DOI: 10.1002/yea.320111403. View

13.

Lehle L, Tanner W . Glycosyl transfer from dolichyl phosphate sugars to endogenous and exogenous glycoprotein acceptors in yeast. Eur J Biochem. 1978; 83(2):563-70. DOI: 10.1111/j.1432-1033.1978.tb12124.x. View

14.

Holm L, Laakso L . Dali server update. Nucleic Acids Res. 2016; 44(W1):W351-5. PMC: 4987910. DOI: 10.1093/nar/gkw357. View

15.

Mercuri E, Messina S, Bruno C, Mora M, Pegoraro E, Comi G . Congenital muscular dystrophies with defective glycosylation of dystroglycan: a population study. Neurology. 2009; 72(21):1802-9. DOI: 10.1212/01.wnl.0000346518.68110.60. View

16.

Matsumoto S, Shimada A, Nyirenda J, Igura M, Kawano Y, Kohda D . Crystal structures of an archaeal oligosaccharyltransferase provide insights into the catalytic cycle of N-linked protein glycosylation. Proc Natl Acad Sci U S A. 2013; 110(44):17868-73. PMC: 3816453. DOI: 10.1073/pnas.1309777110. View

17.

Cheng Y . Membrane protein structural biology in the era of single particle cryo-EM. Curr Opin Struct Biol. 2018; 52:58-63. PMC: 6296881. DOI: 10.1016/j.sbi.2018.08.008. View

18.

Bello L, Melacini P, Pezzani R, DAmico A, Piva L, Leonardi E . Cardiomyopathy in patients with POMT1-related congenital and limb-girdle muscular dystrophy. Eur J Hum Genet. 2012; 20(12):1234-9. PMC: 3499746. DOI: 10.1038/ejhg.2012.71. View

19.

Biancheri R, Falace A, Tessa A, Pedemonte M, Scapolan S, Cassandrini D . POMT2 gene mutation in limb-girdle muscular dystrophy with inflammatory changes. Biochem Biophys Res Commun. 2007; 363(4):1033-7. DOI: 10.1016/j.bbrc.2007.09.066. View

20.

Girrbach V, Zeller T, Priesmeier M . Structure-function analysis of the dolichyl phosphate-mannose: protein O-mannosyltransferase ScPmt1p. J Biol Chem. 2000; 275(25):19288-96. DOI: 10.1074/jbc.M001771200. View