Comparison of lipoprotein lipase glycosylation from adipocytes in lean and obese Zucker rats

Abstract

C‐mannosylation is a type of protein glycosylation involving a covalently attached mannose sugar to the C2 carbon of an indole ring on tryptophan. Lipoprotein lipase (LPL), is an enzyme involved in lipid metabolism, hydrolysis of triglycerides in chylomicrons and very low‐density lipoproteins. LPL is mainly expressed in adipose tissue, muscle tissue, and macrophages, and it has been shown to contain a C‐mannosylated tryptophan in LPL‐overexpressing cell lines. Metabolic disorders, such as diabetes and obesity, leads to a deficiency of LPL function. LPL can be regulated at post‐transcriptional levels in a tissue specific manner that also depends on the nutritional state and hormonal level of the tissue. The goal of this project is to determine whether LPL is C‐mannosylated in adipose tissue from obese and lean Zucker rats. The Zucker fatty rat is a well‐established model of obesity and insulin resistance. Obese Zucker rats have high levels of lipids and cholesterol in their bloodstream, and their adipocytes are increased in size and number. LPL was isolated by immunoprecipitation (IP) using a monoclonal antibody specific for the LPL protein and by using heparin‐sepharose affinity chromatography. The isolated protein was analyzed by mass spectrometry utilizing the peptide mass fingerprint technique and low‐energy CID tandem MS/MS to identify C‐mannosylated tryptophan residues. The results of this experiment further the knowledge of the role that obesity plays in the post‐translational modification of LPL in adipose tissue.Support or Funding InformationNSF‐OIA‐1738707This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.