Tmem27 is upregulated by vitamin D in INS-1 cells and its serum concentrations are low in patients with autoimmune diabetes.
Transmembrane protein 27 (Tmem27), which is expressed in pancreatic β-cells, plays an important role in insulin secretion and pancreatic β-cell proliferation. Analysis of the INS-1 cell proteome using stable isotope labeling by amino acids in cell culture (SILAC) in combination with LC-MS identified Tmem27 as the one of most robustly (up to seven-fold) upregulated proteins after treatment with the active metabolite of vitamin D, 1,25-(OH)2D3. Furthermore, we report that Tmem27 which is cleaved and released from, i.e. pancreatic β-cells, is present in human serum and its levels are significantly lower in subjects with autoimmune diabetes as compared to healthy individuals (13% of the levels). Additionally, Tmem27 correlated positively (0.70) with C-peptide serum levels in healthy subjects. Our data indicate that Tmem27 could be of potential value as a serum marker for the pathogenesis of diabetes and as such may warrant the development of measurement methods with lower limit of detection for its further validation.
Hormone Laboratory, Department of Medical Biochemistry, Oslo University Hospital , Oslo , Norway.
Milaim
M
Pepaj
Nina
N
Gjerlaugsen
Kari
K
Julien
Per M
PM
Thorsby
D000818:Animals; D015415:Biomarkers / Q000097:blood; D002096:C-Peptide / Q000097:blood; D002117:Calcitriol / Q000494:pharmacology; D016022:Case-Control Studies; D002460:Cell Line / Q000187:drug effects; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000097:blood / Q000378:metabolism*; D051381:Rats; D015854:Up-Regulation; D014807:Vitamin D / Q000494:pharmacology*
D015415:Biomarkers; D002096:C-Peptide; C429534:CLTRN protein, human; C504406:Cltrn protein, rat; D008562:Membrane Glycoproteins; D014807:Vitamin D; D002117:Calcitriol
Diabetes; Tmem27; pancreatic β-cell; serum; vitamin D