Single-cell analysis of the mitogen-induced calcium responses of normal and protein kinase C-depleted Swiss 3T3 cells.
AUTOR(ES)
Corps, A N
RESUMO
Single-cell fluorescence image analysis has been used to characterize the mitogen-induced increases in intracellular free [Ca2+] ([Ca2+]i) in control and protein kinase C-depleted Swiss 3T3 cells. More than 80% of the control cells exhibited fast, transient responses to bombesin, vasopressin, or prostaglandin F2 alpha (PGF2 alpha). In contrast, the [Ca2+]i responses induced by platelet-derived growth factor (PDGF) were markedly more heterogeneous, slower, and often biphasic, with fewer cells (60-70%) responding. The peak [Ca2+]i values obtained in response to each mitogen showed substantial variation between cells. Brief pretreatment of the cells with 12-O-tetradecanoyl phorbol 13-acetate (TPA) reduced the [Ca2+]i responses to bombesin, but did not affect the responses to PDGF. Long-term pretreatment of the cells with TPA to down-modulate protein kinase C resulted in substantially prolonged [Ca2+]i responses to bombesin, vasopressin, and PGF2 alpha, but had no such effect on the responses to PDGF. We conclude that differences between the [Ca2+]i responses to bombesin and PDGF, previously reported using cell populations, reflect differences occurring in individual cells, and that the [Ca2+]i responses to bombesin, vasopressin, and PGF2 alpha (but not PDGF) are subject to feedback inhibition via protein kinase C.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=361427Documentos Relacionados
- Ionic responses rapidly elicited by activation of protein kinase C in quiescent Swiss 3T3 cells.
- Respiratory Syncytial Virus Fusion Protein Mediates Inhibition of Mitogen-Induced T-Cell Proliferation by Contact
- Mitogen-induced oscillations of cytosolic Ca2+ and transmembrane Ca2+ current in human leukemic T cells.
- Calcium response of helper T lymphocytes to antigen-presenting cells in a single-cell assay.
- Protein kinase C activation potently down-regulates the expression of its major substrate, 80K, in Swiss 3T3 cells.