Tyrosine kinase receptors concentrated in caveolae-like domains from neuronal plasma membrane.
Recent evidence suggests that tyrosine kinases are highly organized in caveolae of tissue culture cells. We now report the isolation of a membrane domain from neuronal plasma membranes that has the biochemical characteristics of caveolae. A low density membrane (LDM) fraction with the same density as caveolae was highly enriched in tyrosine kinases such as insulin receptors, neurotrophin receptors, Eph family receptors, and Fyn. Grb2, Ras, heterotrimeric GTP-binding proteins, and Erk2 were also concentrated in the LDM. Incubation of the LDM fraction at 37 degrees C stimulated the phosphorylation on tyrosine of multiple, resident proteins, whereas the bulk membrane fraction was devoid of tyrosine kinase activity. The LDM, which makes up approximately 5-10% of the plasma membrane protein, appears to be organized for signal transduction.
Wu
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Department of Cell Biology, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9039, USA.
Butz
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Ying
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Anderson
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D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000737:chemistry; D002784:Cholesterol / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D008854:Microscopy, Electron; D009474:Neurons / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis*; D013109:Sphingomyelins / Q000032:analysis
D013109:Sphingomyelins; D002784:Cholesterol; D020794:Receptor Protein-Tyrosine Kinases