Enhanced binding of low and high density lipoproteins to human adipocyte plasma membranes: effects of temperature and proteases

• Published in: Biochemistry and cell biology Vol. 64; no. 12; p. 1378
• Main Authors: Fong, B S, Rodrigues, P O, Angel, A
• Format: Journal Article
• Language: English
• Published: Canada 01-12-1986
• Subjects: Adipose Tissue - metabolism; Cell Membrane - metabolism; Fibrinolysin - metabolism; Humans; Lipoproteins, HDL - metabolism; Lipoproteins, LDL - metabolism; Peptide Hydrolases - metabolism; Pronase - metabolism; Protease Inhibitors - pharmacology; Temperature; Thrombin - metabolism
• ISSN: 0829-8211
• DOI: 10.1139/o86-181

The specific binding of 125I-labelled low density lipoprotein ([125I]LDL to human adipocyte plasma membranes was higher at 37 than at 0 degree C. Prior treatment of membranes with pronase had no effect on LDL binding measured at 0 degree C but consistently stimulated binding at 37 degrees C. Plasmin was similar to pronase in enhancing LDL-specific binding, but thrombin was not as effective. 125I-labelled high density lipoprotein ([125I]HDL2) specific binding to human adipocyte plasma membranes was similarly sensitive to temperature and pronase treatment. Addition of the protease inhibitor aprotinin in the adipocyte membrane binding assay significantly reduced [125I]LDL binding at 37 degrees C (p less than 0.05), suggesting the involvement of a protease activity intrinsic to the lipoproteins and (or) membranes. These data demonstrate that both LDL and HDL binding in human adipocyte plasma membranes can be "up-regulated" by specific proteolytic perturbations in a temperature-dependent manner.