Dissociation between inositol polyphosphate production and mitogenesis in mouse thymocytes.
Cortical and medullary thymocytes can be separated from each other by virtue of the fact that only cortical thymocytes bear peanut agglutinin (PNA) receptors. The mitogenic responses of subpopulations of thymocytes were studied. We have confirmed the results of Conlon et al. [(1982) J. Immun. 128, 797-801], that lectin-induced stimulation of unseparated cells, and PNA- but not PNA+ thymocytes, results in DNA synthesis. In contrast, both subpopulations, as well as unseparated cells, synthesize DNA in response to the calcium ionophore A23187 in the presence of the phorbol ester TPA, suggesting an impairment of signal transduction in PNA+ cells. However, comparable amounts of inositol phosphates were accumulated in PNA- and PNA+ thymocytes in response to Concanavalin A (Con A). We suggest that mitogenic lectins generate a third signal in addition to elevation of intracellular free calcium concentration and activation of protein kinase C. This signal is generated in PNA- but not in PNA+ thymocytes and is obligatory for lectin-induced stimulation.
Zilberman
Y
Y
Department of Pharmacology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002455:Cell Division; D003208:Concanavalin A / Q000494:pharmacology; D004261:DNA Replication; D007295:Inositol Phosphates / Q000096:biosynthesis*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D010835:Phytohemagglutinins / Q000494:pharmacology; D011975:Receptors, Mitogen / Q000032:analysis; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013950:Thymus Gland / Q000166:cytology*
D007295:Inositol Phosphates; D010835:Phytohemagglutinins; D011975:Receptors, Mitogen; C038223:peanut agglutinin receptor; D003208:Concanavalin A; D000001:Calcimycin; D013755:Tetradecanoylphorbol Acetate