Site-specific GlcNAcylation of human erythrocyte proteins: Potential biomarker(s) for diabetes

Zihao Wang, Kyoungsook Park, Frank Comer, Linda C. Hsieh-Wilson, Christopher D. Saudek, Gerald Warren Hart

Research output: Contribution to journalArticlepeer-review

Abstract

OBJECTIVE-O-linked N-acetylglucosamine (O-GlcNAc) is up-regulated in diabetic tissues and plays a role in insulin resistance and glucose toxicity. Here, we investigated the extent of GlcNAcylation on human erythrocyte proteins and compared site-specific GlcNAcylation on erythrocyte proteins from diabetic and normal individuals. RESEARCH DESIGN AND METHODS-GlcNAcylated erythrocyte proteins or GlcNAcylated peptides were tagged and selectively enriched by a chemoenzymatic approach and identified by mass spectrometry. The enrichment approach was combined with solid-phase chemical derivatization and isotopic labeling to detect O-GlcNAc modification sites and to compare site-specific O-GlcNAc occupancy levels between normal and diabetic erythrocyte proteins. RESULTS-The enzymes that catalyze the cycling (addition and removal) of O-GlcNAc were detected in human erythrocytes. Twenty-five GlcNAcylated erythrocyte proteins were identified. Protein expression levels were compared between diabetic and normal erythrocytes. Thirty-five O-GlcNAc sites were reproducibly identified, and their site-specific O-GlcNAc occupancy ratios were calculated. CONCLUSIONS-GlcNAcylation is differentially regulated at individual sites on erythrocyte proteins in response to glycemic status. These data suggest not only that site-specific O-GlcNAc levels reflect the glycemic status of an individual but also that O-GlcNAc site occupancy on erythrocyte proteins may be eventually useful as a diagnostic tool for the early detection of diabetes.

Original languageEnglish (US)
Pages (from-to)309-317
Number of pages9
JournalDiabetes
Volume58
Issue number2
DOIs
StatePublished - Feb 2009

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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