scholarly journals LIN-9 Phosphorylation on Threonine-96 Is Required for Transcriptional Activation of LIN-9 Target Genes and Promotes Cell Cycle Progression

PLoS ONE ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. e87620 ◽  
Author(s):  
Frank Eckerdt ◽  
Mathew Perez-Neut ◽  
Oscar R Colamonici
2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Yiming He ◽  
Mingxi Gan ◽  
Yanan Wang ◽  
Tong Huang ◽  
Jianbin Wang ◽  
...  

AbstractGrainyhead-like 1 (GRHL1) is a transcription factor involved in embryonic development. However, little is known about the biological functions of GRHL1 in cancer. In this study, we found that GRHL1 was upregulated in non-small cell lung cancer (NSCLC) and correlated with poor survival of patients. GRHL1 overexpression promoted the proliferation of NSCLC cells and knocking down GRHL1 inhibited the proliferation. RNA sequencing showed that a series of cell cycle-related genes were altered when knocking down GRHL1. We further demonstrated that GRHL1 could regulate the expression of cell cycle-related genes by binding to the promoter regions and increasing the transcription of the target genes. Besides, we also found that EGF stimulation could activate GRHL1 and promoted its nuclear translocation. We identified the key phosphorylation site at Ser76 on GRHL1 that is regulated by the EGFR-ERK axis. Taken together, these findings elucidate a new function of GRHL1 on regulating the cell cycle progression and point out the potential role of GRHL1 as a drug target in NSCLC.


2018 ◽  
Vol 38 (17) ◽  
Author(s):  
Shakhawoat Hossain ◽  
Hiroaki Iwasa ◽  
Aradhan Sarkar ◽  
Junichi Maruyama ◽  
Kyoko Arimoto-Matsuzaki ◽  
...  

ABSTRACT RASSF6 is a member of the tumor suppressor Ras association domain family (RASSF) proteins. RASSF6 is frequently suppressed in human cancers, and its low expression level is associated with poor prognosis. RASSF6 regulates cell cycle arrest and apoptosis and plays a tumor suppressor role. Mechanistically, RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. However, RASSF6 also induces cell cycle arrest and apoptosis in a p53-negative background, which implies that the tumor suppressor function of RASSF6 does not depend solely on p53. In this study, we revealed that RASSF6 mediates cell cycle arrest and apoptosis via pRb. RASSF6 enhances the interaction between pRb and protein phosphatase. RASSF6 also enhances P16INK4A and P14ARF expression by suppressing BMI1. In this way, RASSF6 increases unphosphorylated pRb and augments the interaction between pRb and E2F1. Moreover, RASSF6 induces TP73 target genes via pRb and E2F1 in a p53-negative background. Finally, we confirmed that RASSF6 depletion induces polyploid cells in p53-negative HCT116 cells. In conclusion, RASSF6 behaves as a tumor suppressor in cancers with loss of function of p53, and pRb is implicated in this function of RASSF6.


Oncogene ◽  
2003 ◽  
Vol 22 (23) ◽  
pp. 3645-3654 ◽  
Author(s):  
Asra Mirza ◽  
Qun Wu ◽  
Luquan Wang ◽  
Terri McClanahan ◽  
W Robert Bishop ◽  
...  

2007 ◽  
Vol 27 (23) ◽  
pp. 8364-8373 ◽  
Author(s):  
J. Veis ◽  
H. Klug ◽  
M. Koranda ◽  
G. Ammerer

ABSTRACT In budding yeast (Saccharomyces cerevisiae), the periodic expression of the G2/M-specific gene CLB2 depends on a DNA binding complex that mediates its repression during G1 and activation from the S phase to the exit of mitosis. The switch from low to high expression levels depends on the transcriptional activator Ndd1. We show that the inactivation of the Sin3 histone deacetylase complex bypasses the essential role of Ndd1 in cell cycle progression. Sin3 and its catalytic subunit Rpd3 associate with the CLB2 promoter during the G1 phase of the cell cycle. Both proteins dissociate from the promoter at the onset of the S phase and reassociate during G2 phase. Sin3 removal coincides with a transient increase in histone H4 acetylation followed by the expulsion of at least one nucleosome from the promoter region. Whereas the first step depends on Cdc28/Cln1 activity, Ndd1 function is required for the second step. Since the removal of Sin3 is independent of Ndd1 recruitment and Cdc28/Clb activity it represents a unique regulatory step which is distinct from transcriptional activation.


2006 ◽  
Vol 173 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Daniela Dorner ◽  
Sylvia Vlcek ◽  
Nicole Foeger ◽  
Andreas Gajewski ◽  
Christian Makolm ◽  
...  

Lamina-associated polypeptide (LAP) 2α is a nonmembrane-bound LAP2 isoform that forms complexes with nucleoplasmic A-type lamins. In this study, we show that the overexpression of LAP2α in fibroblasts reduced proliferation and delayed entry into the cell cycle from a G0 arrest. In contrast, stable down-regulation of LAP2α by RNA interference accelerated proliferation and interfered with cell cycle exit upon serum starvation. The LAP2α-linked cell cycle phenotype is mediated by the retinoblastoma (Rb) protein because the LAP2α COOH terminus directly bound Rb, and overexpressed LAP2α inhibited E2F/Rb-dependent reporter gene activity in G1 phase in an Rb-dependent manner. Furthermore, LAP2α associated with promoter sequences in endogenous E2F/Rb-dependent target genes in vivo and negatively affected their expression. In addition, the expression of LAP2α in proliferating preadipocytes caused the accumulation of hypophosphorylated Rb, which is reminiscent of noncycling cells, and initiated partial differentiation into adipocytes. The effects of LAP2α on cell cycle progression and differentiation may be highly relevant for the cell- and tissue-specific phenotypes observed in laminopathic diseases.


2009 ◽  
Vol 69 (22) ◽  
pp. 8563-8571 ◽  
Author(s):  
K. Lefkimmiatis ◽  
M. F. Caratozzolo ◽  
P. Merlo ◽  
A. M. D'Erchia ◽  
B. Navarro ◽  
...  

2018 ◽  
Author(s):  
Shakhawoat Hossain ◽  
Hiroaki Iwasa ◽  
Aradhan Sarkar ◽  
Junichi Maruyama ◽  
Kyoko Arimoto-Matsuzaki ◽  
...  

ABSTRACTRASSF6 is a member of the tumor suppressor Ras-association domain family (RASSF) proteins. RASSF6 is frequently suppressed in human cancers and its low expression is associated with poor prognosis. RASSF6 regulates cell cycle arrest and apoptosis and plays a tumor suppressor role. Mechanistically, RASSF6 blocks MDM2-mediated p53 degradation and enhances p53 expression. However, RASSF6 also induces cell cycle arrest and apoptosis in the p53-negative background, which implies that the tumor suppressor function of RASSF6 does not depend solely on p53. In this study, we have revealed that RASSF6 mediates cell cycle arrest and apoptosis via pRb. RASSF6 enhances the interaction between pRb and protein phosphatase. RASSF6 also enhances P16INK4A and P14ARF expression through suppressing BMI1. In this way, RASSF6 increases unphosphorylated pRb and augments the interaction between pRb and E2F1. Moreover, RASSF6 induces TP73-target genes via pRb and E2F1 in the p53-negative background. Finally, we confirmed that RASSF6 depletion induces polypoid cells in p53-negative HCT116 cells. In conclusion, RASSF6 behaves as a tumor suppressor in cancers with the loss-of-function of p53, and pRb is implicated in this function of RASSF6.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 881-881
Author(s):  
Hee-Don Chae ◽  
Bryan Mitton ◽  
Kathleen Sakamoto

Abstract CREB (cAMP Response Element Binding protein) is a transcription factor overexpressed in normal and neoplastic myelopoiesis and regulates cell cycle progression, although its oncogenic mechanism has not been well characterized. Replication Factor C3 (RFC3), a 38 kDa subunit of the RFC complex, is required for chromatin loading of proliferating cell nuclear antigen (PCNA) which is a sliding clamp platform for recruiting numerous proteins in DNA replication and repair processes. CREB1 expression was coupled with RFC3 expression during the G1/S progression in the KG-1 acute myeloid leukemia (AML) cell line, suggesting that RFC3 and CREB1 might be target genes of E2F, a key transcriptional regulator of the G1/S progression. Though there were two potential E2F binding sites in the RFC3 promoter region, chromatin immunoprecipitation assays provided no evidence for E2F1 binding to the RFC3 promoter, whereas E2F1 could directly act on the CREB1 expression. Treatment with the cyclin-dependent kinase (CDK) inhibitor AT7519 decreased expression of CREB1 and RFC3 as well as well-known E2F target genes such as CCNE1, CCNA2 and CCNB1 in KG-1 cells. These results indicate that CREB1 overexpression, a potentially important prognostic marker in leukemia patients, may be associated with dysregulated CDK-E2F activity in leukemia. There was also a direct correlation between the expression of RFC3 and CREB1 in human AML cell lines as well as in AML cells from patients. CREB interacted directly with the CRE site in RFC3 promoter region. CREB knockdown primarily inhibited G1/S cell cycle transition, decreasing expression of RFC3 as well as PCNA loading onto chromatin. Exogenous expression of RFC3 was sufficient to rescue the impaired G1/S progression and PCNA chromatin loading [Chromatin-bound PCNA-positive cells (%), control vs. CREB-knockdown vs. CREB-knockdown with RFC3 overexpression, 8h after release from mitotic arrest: 66.87 +/– 0.90 vs. 24.77 +/– 0.99 vs. 79.17 +/– 0.12, n=3, p< 0.01, mean +/– SEM] caused by CREB knockdown. Taken together, our results suggest that RFC3 may play a role in neoplastic myelopoiesis by promoting the G1/S progression, and its expression is regulated by CREB. These data provide new insight into CREB-driven regulation of the cell cycle in AML cells, and may contribute to leukemogenesis associated with CREB overexpression. Disclosures No relevant conflicts of interest to declare.


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