scholarly journals The Carboxyl-terminal Domain of the Granulocyte Colony-stimulating Factor Receptor Uncouples Ribosomal Biogenesis from Cell Cycle Progression in Differentiating 32D Myeloid Cells

2001 ◽  
Vol 276 (52) ◽  
pp. 49410-49418 ◽  
Author(s):  
Sandra L. Kroll ◽  
Diane Barth-Baus ◽  
Jack O. Hensold
2000 ◽  
Vol 20 (20) ◽  
pp. 7726-7734 ◽  
Author(s):  
Eiji Nishiwaki ◽  
Saralinda L. Turner ◽  
Susanna Harju ◽  
Shiro Miyazaki ◽  
Masahide Kashiwagi ◽  
...  

ABSTRACT The eukaryotic cell cycle is regulated by cyclin-dependent kinases (CDKs). CDK4 and CDK6, which are activated by D-type cyclins during the G1 phase of the cell cycle, are thought to be responsible for phosphorylation of the retinoblastoma gene product (pRb). The tumor suppressor p16INK4A inhibits phosphorylation of pRb by CDK4 and CDK6 and can thereby block cell cycle progression at the G1/S boundary. Phosphorylation of the carboxyl-terminal domain (CTD) of the large subunit of RNA polymerase II by general transcription factor TFIIH is believed to be an important regulatory event in transcription. TFIIH contains a CDK7 kinase subunit and phosphorylates the CTD. We have previously shown that p16INK4A inhibits phosphorylation of the CTD by TFIIH. Here we report that the ability of p16INK4A to inhibit CDK7-CTD kinase contributes to the capacity to induce cell cycle arrest. These results suggest that p16INK4A may regulate cell cycle progression by inhibiting not only CDK4-pRb kinase activity but also by modulating CDK7-CTD kinase activity. Regulation of CDK7-CTD kinase activity by p16INK4A thus may represent an alternative pathway for controlling cell cycle progression.


1999 ◽  
Vol 339 (3) ◽  
pp. 517-524 ◽  
Author(s):  
Nicholas J. WILSON ◽  
Suzanne T. MOSS ◽  
Xavier F. CSAR ◽  
Alister C. WARD ◽  
John A. HAMILTON

Colony-stimulating factor 1 (CSF-1) is required for the development of monocytes/macrophages from progenitor cells and for the survival and activation of mature macrophages. The receptor for CSF-1 is the product of the c-fms proto-oncogene, which, on binding ligand, can stimulate a mitogenic response in the appropriate cells. To investigate which genes are regulated in response to CSF-1-stimulation in murine bone-marrow-derived macrophages (BMM), we employed mRNA differential display reverse transcriptase-mediated PCR to identify cDNA species induced by CSF-1. Both Northern and Western blot analyses confirmed the increased expression of one of the cDNA species identified as coding for the catalytic subunit of protein phosphatase 2A (PP2A), an observation not previously reported during the response to a growth factor. To determine the significance of the increased expression of PP2A in response to CSF-1, the PP2A inhibitor okadaic acid (OA) was added to CSF-1-treated BMM and found to inhibit DNA synthesis in a dose-dependent manner. Further analysis with flow cytometry in the presence of OA led to the novel conclusion that PP2A activity is critical for CSF-1-driven BMM cell cycle progression in both early G1 and S phases. Surprisingly, in the light of previous studies with other cells, the PP2A-dependent proliferation could be dissociated from activation by extracellular signal-regulated protein kinase (ERK) in macrophages because OA did not affect either the basal or CSF-1-induced ERK activity in BMM. Two-dimensional SDS/PAGE analysis of lysates of 32P-labelled BMM, which had been treated with CSF-1 in the presence or absence of OA, identified candidate substrates for PP2A.


2000 ◽  
Vol 113 (17) ◽  
pp. 3063-3072 ◽  
Author(s):  
J. Zhao ◽  
C. Zheng ◽  
J. Guan

We have previously identified FAK and its associated signaling pathways as a mediator of cell cycle progression by integrins. In this report, we have analyzed the potential role and mechanism of Pyk2, a tyrosine kinase closely related to FAK, in cell cycle regulation by using tetracycline-regulated expression system as well as chimeric molecules. We have found that induction of Pyk2 inhibited G(1) to S phase transition whereas comparable induction of FAK expression accelerated it. Furthermore, expression of a chimeric protein containing Pyk2 N-terminal and kinase domain and FAK C-terminal domain (PFhy1) increased cell cycle progression as FAK. Conversely, the complementary chimeric molecule containing FAK N-terminal and kinase domain and Pyk2 C-terminal domain (FPhy2) inhibited cell cycle progression to an even greater extent than Pyk2. Biochemical analyses indicated that Pyk2 and FPhy2 stimulated JNK activation whereas FAK or PFhy1 had little effect on it, suggesting that differential activation of JNK by Pyk2 may contribute to its inhibition of cell cycle progression. In addition, Pyk2 and FPhy2 to a greater extent also inhibited Erk activation in cell adhesion whereas FAK and PFhy1 stimulated it, suggesting a role for Erk activation in mediating differential regulation of cell cycle by Pyk2 and FAK. A role for Erk and JNK pathways in mediating the cell cycle regulation by FAK and Pyk2 was also confirmed by using chemical inhibitors for these pathways. Finally, we showed that while FAK and PFhy1 were present in focal contacts, Pyk2 and FPhy2 were localized in the cytoplasm. Interestingly, both Pyk2 and FPhy2 (to a greater extent) were tyrosine phosphorylated and associated with Src and Fyn. This suggested that they may inhibit Erk activation in an analogous manner as the mislocalized FAK mutant (Δ)C14 described previously by competing with endogenous FAK for binding signaling molecules such as Src and Fyn. This model is further supported by an inhibition of endogenous FAK association with active Src by Pyk2 and FPhy2 and a partial rescue by FAK of Pyk2-mediated cell cycle inhibition.


2006 ◽  
Vol 26 (21) ◽  
pp. 8052-8060 ◽  
Author(s):  
Ewa Sicinska ◽  
Young-Mi Lee ◽  
Judith Gits ◽  
Hirokazu Shigematsu ◽  
Qunyan Yu ◽  
...  

ABSTRACT The proliferation of neutrophil granulocyte lineage is driven largely by granulocyte colony-stimulating factor (G-CSF) acting via the G-CSF receptors. In this study, we show that mice lacking cyclin D3, a component of the core cell cycle machinery, are refractory to stimulation by the G-CSF. Consequently, cyclin D3-null mice display deficient maturation of granulocytes in the bone marrow and have reduced levels of neutrophil granulocytes in their peripheral blood. The mutant mice are unable to mount a normal response to bacterial challenge and succumb to microbial infections. In contrast, the expansion of hematopoietic stem cells and lineage-committed myeloid progenitors proceeds relatively normally in mice lacking cyclin D3, revealing that the requirement for cyclin D3 function operates at later stages of neutrophil development. Importantly, we verified that this requirement is specific to cyclin D3, as mice lacking other G1 cyclins (D1, D2, E1, or E2) display normal granulocyte counts. Our analyses revealed that in the bone marrow cells of wild-type mice, activation of the G-CSF receptor leads to upregulation of cyclin D3. Collectively, these results demonstrate that cyclin D3 is an essential cell cycle recipient of G-CSF signaling, and they provide a molecular link of how G-CSF-dependent signaling triggers cell proliferation.


Blood ◽  
1993 ◽  
Vol 81 (4) ◽  
pp. 916-922 ◽  
Author(s):  
ES Medlock ◽  
DL Kaplan ◽  
M Cecchini ◽  
TR Ulich ◽  
J del Castillo ◽  
...  

Abstract We studied the effect of recombinant human granulocyte colony- stimulating factor (rhG-CSF) administration to pregnant rats upon fetal and neonatal myelopoiesis. Pregnant rats were treated with rhG-CSF twice daily for 2, 4, and 6 days before parturition. rhG-CSF crossed the placenta and reached peak fetal serum concentrations 4 hours after administration. Peak fetal serum levels were 1,000-fold lower than levels detected in the dam. Hematopoietic effects of rhG-CSF were assessed by cytologic analysis of the newborn blood, spleen, bone marrow, thymus, and liver. White blood cell counts were increased twofold to fourfold in newborns. This increase was due to circulating numbers of polymorphonuclear cells (PMN). rhG-CSF induced a myeloid hyperplasia in the newborn marrow consisting of immature and mature myeloid cells in the day-2 and day-4 treated pups. Bone marrow of pups treated for 6 days contained mostly hyper-segmented PMN with little or no increase in myeloid precursors. An increase in the number of postmitotic (PMN, bands, and metamyelocytes) and mitotic (promyeloblasts, myeloblasts, and metamyeloblasts) myeloid cells in the spleen of neonates was observed. No change was detected in splenic lymphocytes or monocytes. No effect of rhG-CSF was noted in the newborn liver or thymus. These results demonstrate that maternally administered rhG-CSF crosses the placenta and specifically induces bone marrow and spleen myelopoiesis in the fetus and neonate. The significant myelopoietic effects of rhG-CSF at low concentrations in the fetus suggest an exquisite degree of developmental sensitivity to this cytokine and may provide enhanced defense mechanisms to the neonate.


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