Signal Transduction and Glycophosphatidylinositol-Linked Proteins (LYN, LCK, CD4, CD45, G Proteins, and CD55) Selectively Localize in Triton-Insoluble Plasma Membrane Domains of Human Leukemic Cell Lines and Normal Granulocytes

• Published in: Blood 1996-05, Vol.87 (9), p.3783-3794
• Main Authors: Parolini, I., Sargiacomo, M., Lisanti, M.P., Peschle, C.
• Format: Article
• Language: English
• Subjects: Antigens, CD - metabolism; Biological and medical sciences; Cell Membrane - metabolism; Cell physiology; Cells, Cultured; Fundamental and applied biological sciences. Psychology; Glycosylphosphatidylinositols - metabolism; Granulocytes - metabolism; Humans; Leukemia - metabolism; Membrane Proteins - metabolism; Molecular and cellular biology; Octoxynol; Signal Transduction
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V87.9.3783.bloodjournal8793783

Src-family nonreceptor protein tyrosine kinases (NRPTK) are associated with cell surface receptors in large detergent-resistant complexes: in epithelial cells, yes is selectively located in vesicle structures containing caveolin (“caveolae”). These formations are typically also endowed with glyco-phosphatidylinositol (GPI)-anchored proteins. In the present study, we observed Ick, lyn, src, hck, CD4, CD45, G proteins, and CD55 (decay-accelerating factor) expression in the buoyant low-density Triton-insoluble (LDTI) fraction of selected leukemic cell lines and granulocytes. We provide a detailed analysis of the two most highly expressed NRPTK, p53/p56lyn and p56lck, which are involved in the transduction of signals for proliferation and differentiation of monocytes/B lymphocytes and T lymphocytes, respectively. We show that lyn is selectively recovered in LDTI complexes isolated from human leukemic cell lines (promyelocytic [HL-60], erythroid [K562] and B-lymphoid [697]) and from normal human granulocytes, and that Ick is recovered from LDTI fractions of leukemic T- and B-lymphoid cell lines (CEM, 697). In LDTI fractions of leukemic cells, Ick and lyn are enriched 100-fold as compared with the total cell lysates. Analysis of these fractions by electron microscopy shows the presence of 70-to 200-nm vesicles: lyn and Ick are homogenously distributed in the vesicles, as revealed by an immunogold labeling procedure. These novel results propose a role for these vesicles in signal transduction mechanisms of normal and neoplastic hematopoietic cells. In support of this hypothesis, we further observed that molecules participating in B- and T-cell receptor activation cofractionate in the LDTI fractions, CD45/lyn (B cells) and CD45/lck/CD4 (T cells).