title: Growth factor-dependent proliferative stimulation of hematopoietic cells is associated with the modulation of cytoplasmic and nuclear 68-Kd calmodulin-binding protein.
abstract: Calcium and calmodulin (CaM) are known to play critical roles in controlling cell cycle progression in a variety of cells. We observed that the CaM antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalensulfonamide hydrochloride (W-7), inhibited 3H-thymidine incorporation into DNA of factor-dependent hematopoietic cells. To delineate the role of CaM in proliferation of hematopoietic cells, we have investigated intracellular distribution of specific CaM-binding proteins (CaM-BPs) in response to hematopoietic growth factors in FDC-P1, 32D, NFS-60, and T1165 cells. Each of these cell lines, when deprived of cytokines for 16 to 18 hours, essentially ceased proliferation, even in the presence of fetal calf serum. Concomitant to the cessation of proliferation, there was a dramatic depletion of a specific CaM-BP of about 68 Kd in both their cytoplasmic and nuclear fractions. Within 6 to 12 hours of reexposure to proliferation-specific cytokines, there was a restoration of the nuclear as well as cytoplasmic 68-Kd CaM-BP. Furthermore, such an induction and nuclear localization of the 68-Kd CaM-BP by the cytokines coincided temporally with the progression of synchronized FDC-P1 cells from G1 to S phase. By contrast, colony-stimulating factor-1 (CSF-1)-dependent bone marrow macrophages and BAC-1 cells did not exhibit 68-Kd CaM-BP in the nuclear or cytoplasmic fractions. These studies suggest that while hematopoietic growth factor granulocyte CSF-, granulocyte-macrophage CSF-, interleukin-3 (IL-3)-, or IL-6-, whose receptors are members of the hematopoietin receptor family, induced cell proliferation is associated with a common mechanism involving nuclear localization of the 68-Kd CaM-BP, the CSF-1-induced proliferation seems to involve 68-Kd CaM-BP-independent pathways.
authors.affiliation: Department of Obstetrics and Gynecology, University of Virginia Health Sciences Center, Charlottesville 22908.
authors.forename: G P
authors.initials: GP
authors.lastname: Reddy
authors.forename: W C
authors.initials: WC
authors.lastname: Reed
authors.forename: D H
authors.initials: DH
authors.lastname: Deacon
authors.forename: P J
authors.initials: PJ
authors.lastname: Quesenberry
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002148:Calmodulin-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D007377:Interleukin-3 / Q000494:pharmacology; D007532:Isoleucine / Q000378:metabolism; D007700:Kinetics; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008970:Molecular Weight; D013449:Sulfonamides / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
chemical_list: D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D013449:Sulfonamides; D007532:Isoleucine; C017967:W 7; C034700:N-(6-aminohexyl)-1-naphthalenesulfonamide; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013936:Thymidine