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Updated: Aug 12, 2026

An Adipocyte Cell Culture Model to Study the Impact of Protein and Micro-RNA Modulation on Adipocyte Function
Published on: May 4, 2021
Insulin-dependent phosphorylation of a 70-kDa protein in light microsomes from rat adipocytes
C Martinez1, G Vallega, P F Pilch
1Department of Biochemistry, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts, 02118, USA.
Abstract:
In order to discover possibly novel insulin receptor substrates and/or downstream targets in the insulin signaling pathway, we established a cell-free system for this purpose using purified insulin receptor and subcellular fractions from rat adipocytes as a sourse of cellular substrates. Under these conditions, we have found a 70-kDa protein (pp70) in fat cells that is tyrosine-phosphorylated by the activated insulin receptor. Using sucrose velocity gradient sedimentation we also show that pp70 cofractionate a particulate fraction containing IRS-1 but not with GLUT-4 vesicle-enriched fractions. Our results suggest that pp70 may be an endogenous substrate for the insulin receptor tyrosine kinase.
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