Regulation of the SHP-2 tyrosine phosphatase by a novel cholesterol- and cell confluence-dependent mechanism
Biochemistry & Molecular Pharmacology
Graduate School of Biomedical Sciences; Program in Molecular Medicine
Medical Subject Headings
Animals; Annexin A2; Aorta; Cattle; Cell Adhesion; Cell Division; Cell Line; Cell Membrane; Cells, Cultured; Cholesterol; Cyclodextrins; Digitonin; Endothelium, Vascular; *Gene Expression Regulation, Enzymologic; Indicators and Reagents; Intracellular Signaling Peptides and Proteins; Microscopy, Fluorescence; Phosphorylation; Precipitin Tests; Protein Binding; Protein Tyrosine Phosphatase, Non-Receptor Type 11; Protein Tyrosine Phosphatases; Protein-Tyrosine Kinases; SH2 Domain-Containing Protein Tyrosine Phosphatases; Signal Transduction; Subcellular Fractions; Tyrosine; src Homology Domains
Life Sciences | Medicine and Health Sciences
Endothelial cells approaching confluence exhibit marked decreases in tyrosine phosphorylation of receptor tyrosine kinases and adherens junctions proteins, required for cell cycle arrest and adherens junctions stability. Recently, we demonstrated a close correlation in endothelial cells between membrane cholesterol and tyrosine phosphorylation of adherens junctions proteins. Here, we probe the mechanistic basis for this correlation. We find that as endothelial cells reach confluence, the tyrosine phosphatase SHP-2 is recruited to a low-density membrane fraction in a cholesterol-dependent manner. Binding of SHP-2 to this fraction was not abolished by phenyl phosphate, strongly suggesting that this binding was mediated by other regions of SHP-2 beside its SH2 domains. Annexin II, previously implicated in cholesterol trafficking, was associated in a complex with SHP-2, and both proteins localized to adhesion bands in confluent endothelial monolayers. These studies reveal a novel, cholesterol-dependent mechanism for the recruitment of signaling proteins to specific plasma membrane domains via their interactions with annexin II.
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Citation: J Biol Chem. 2003 May 16;278(20):18360-7. Epub 2003 Feb 27. Link to article on publisher's site
The Journal of biological chemistry
Burkart, Alison; Samii, Babak; Corvera, Silvia; and Shpetner, Howard S., "Regulation of the SHP-2 tyrosine phosphatase by a novel cholesterol- and cell confluence-dependent mechanism" (2003). GSBS Student Publications. 154.