protein O-mannosyl-transferase 2; dolichyl-phosphate-mannose-protein mannosyltransferase 2 (POMT2)

Function

• transfers mannosyl residues to the hydroxyl group of Ser or Thr
• coexpression of both POMT1 & POMT2 is necessary for enzyme activity, expression of either POMT1 or POMT2 alone is insufficient
• protein modification; protein glycosylation
• interacts with POMT1 (probable)

dolichyl phosphate D-mannose + protein = dolichyl phosphate + O-D-mannosylprotein

Cofactor:

• Mg+2
• Mn+2 & Ca+2 suppress enzyme activity

Structure

• N-glycosylated
• belongs to the glycosyltransferase 39 family
• contains 3 MIR domains

Compartment

• endoplasmic reticulum membrane
• multi-pass membrane protein

Alternative splicing

• named isoforms=2
• at least one isoform may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

Expression

• highly expressed in testis
• detected at low levels in most tissues

Pathology

• defects in the POMT2 gene associated with variations in the Walker-Warburg syndrome
• defects in POMT2 are the cause of limb-girdle muscular dystrophy type 2N

More general terms

• transmembrane 10 protein
• glycosyltransferase
• glycoprotein

Additional terms

• dolichol phosphate

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=29954
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:29954
• OMIM: https://mirror.omim.org/entry/607439
• OMIM: https://mirror.omim.org/entry/613150
• OMIM: https://mirror.omim.org/entry/613156
• OMIM: https://mirror.omim.org/entry/613158
• UniProt: http://www.uniprot.org/uniprot/Q9UKY4.html