Distribution of intracellular free calcium in quiescent BALB/c 3T3 cells stimulated by platelet-derived growth factor.
A digital imaging microscope and fluorescent Ca(2+)-sensitive probe (Fura 2) were used to study the spatial location and time course of increases in free intracellular calcium (Cai) induced by platelet-derived growth factor (PDGF). Microinjection of Fura 2 acid avoided problems of incomplete deesterification of Fura 2-acetoxymethyl ester (Fura 2/AM) and dye localization in cellular organelles. PDGF stimulated a rapid increase in Cai (up to 8-fold increase) in both the nucleus and the cytoplasm in approximately half of the quiescent BALB/c 3T3 cells. Cai changes were both spatially and temporally heterogeneous, the latter including both transient (1-2 min) and prolonged increases (greater than 5 min) in the same cell. PDGF stimulated mitogenesis and Cai increases in approximately the same percentage of cells. Moreover, large intracellular concentrations of a Ca2+ buffer (Quin 2) inhibited both Cai increases and mitogenesis stimulated by PDGF. Thus, Ca2+ increases in the nuclear and/or cytosolic compartments appear to be required for the stimulation of mitogenesis by polypeptide growth factors such as PDGF.
Tucker
R W
RW
Johns Hopkins Oncology Center, Baltimore, MD 21205.
Fay
F S
FS
D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis*; D005453:Fluorescence; D005456:Fluorescent Dyes; D051379:Mice; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D013997:Time Factors
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D010982:Platelet-Derived Growth Factor; C035738:Quin2-acetoxymethyl ester; D004247:DNA; D002118:Calcium