THY-1 GLYCOPROTEIN AND SRC-LIKE PROTEIN-TYROSINE KINASE P53 P56(LYN) ARE ASSOCIATED IN LARGE DETERGENT-RESISTANT COMPLEXES IN RAT BASOPHILIC LEUKEMIA-CELLS/
L. Draberova et P. Draber, THY-1 GLYCOPROTEIN AND SRC-LIKE PROTEIN-TYROSINE KINASE P53 P56(LYN) ARE ASSOCIATED IN LARGE DETERGENT-RESISTANT COMPLEXES IN RAT BASOPHILIC LEUKEMIA-CELLS/, Proceedings of the National Academy of Sciences of the United Statesof America, 90(8), 1993, pp. 3611-3615
Thy-1 is a surface glycoprotein that is attached to the plasma membran
e by a glycosyl-phosphatidylinositol anchor. Crosslinking of Thy-1 in
rat mast cells and basophilic leukemia cells (RBL-2H3) induces cell ac
tivation including histamine release and tyrosine phosphorylation of s
everal proteins. Here we show that glycosyl-phosphatidylinositol-linke
d Thy-1 forms noncovalent complexes with src-related protein-tyrosine
kinase p53/p56lyn and other protein-tyrosine kinases and/or their subs
trates. These complexes are resistant to solubilization by a nonionic
detergent, sedimentable at 200,000 x g, and very large (>10 MDa) as de
termined by gel chromatography. Activation of RBL-2H3 cells by crossli
nking of the high-affinity IgE receptors resulted in decreased recover
y of the complexes. The combined data indicate the existence of large
detergent-resistant domains in the surface membrane of mast cells that
may play an important role in their activation.