scholarly journals P-Rex1 Controls Sphingosine 1-Phosphate Receptor Signalling, Morphology, and Cell-Cycle Progression in Neuronal Cells

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2474
Author(s):  
Elizabeth Hampson ◽  
Elpida Tsonou ◽  
Martin J. Baker ◽  
David C. Hornigold ◽  
Roderick E. Hubbard ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Neuronal Cell ◽  
Nucleotide Exchange ◽  
Camp Production ◽  
Cycle Progression ◽  
Functional Roles ◽  
Cell Responses ◽  
Sphingosine 1 Phosphate ◽  
Neuronal Pc12 Cells

P-Rex1 is a guanine-nucleotide exchange factor (GEF) that activates Rac-type small G proteins in response to the stimulation of a range of receptors, particularly G protein-coupled receptors (GPCRs), to control cytoskeletal dynamics and other Rac-dependent cell responses. P-Rex1 is mainly expressed in leukocytes and neurons. Whereas its roles in leukocytes have been studied extensively, relatively little is known about its functions in neurons. Here, we used CRISPR/Cas9-mediated P-Rex1 deficiency in neuronal PC12 cells that stably overexpress the GPCR S1PR1, a receptor for sphingosine 1-phosphate (S1P), to investigate the role of P-Rex1 in neuronal GPCR signalling and cell responses. We show that P-Rex1 is required for the S1P-stimulated activation of Rac1 and Akt, basal Rac3 activity, and constitutive cAMP production in PC12-S1PR1 cells. The constitutive cAMP production was not due to increased expression levels of major neuronal adenylyl cyclases, suggesting that P-Rex1 may regulate adenylyl cyclase activity. P-Rex1 was required for maintenance of neurite protrusions and spreading in S1P-stimulated PC12-S1PR1 cells, as well as for cell-cycle progression and proliferation. In summary, we identified novel functional roles of P-Rex1 in neuronal Rac, Akt and cAMP signalling, as well as in neuronal cell-cycle progression and proliferation.

Abstract W P198: Sphingomyelin Synthases Regulate Neuronal Cell Proliferation and Cell Cycle Progression

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Umadevi V Wesley ◽  
Daniel Tremmel ◽  
Robert Dempsey
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Neuronal Cell ◽  
Artery Occlusion ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Cycle Regulation ◽  
Cerebral Artery Occlusion

Introduction: The molecular mechanisms of cerebral ischemia damage and protection are not completely understood, but a number of reports implicate the contribution of lipid metabolism and cell-cycle regulating proteins in stroke out come. We have previously shown that tricyclodecan-9-yl-xanthogenate (D609) resulted in increased ceramide levels after transient middle cerebral artery occlusion (tMCAO) in spontaneously hypertensive rat (SHR). We hypothesized that D609 induced cell cycle arrest probably by inhibiting sphingomyelin synthase (SMS). In this study, we examined the direct effects of SMS on cell cycle progression and proliferation of neuroblast cells. Methods: Ischemia was induced by middle cerebral artery occlusion (MCAO) and reperfusion. Expression levels were measured by western blot analysis, RT-PCR, and Immunofluorescence staining. SMS1 and 2 expressions were silenced by stable transfection with SMS1/2-targeted shRNA. Cell cycle analysis was performed using Flow cytometry. Data were analyzed using MODFIT cell cycle analysis program. Cell proliferation rate was measured by MTT assay. Results: We have identified that the expression of SMS1is significantly up-regulated in the ischemic hemisphere following MCAO. Neuro-2a cells transfected with SMS specific ShRNA acquired more neuronal like phenotype and exhibited decreased proliferation rate. Also, silencing of both SMS1 and 2 induced cell-cycle arrest as shown by significantly increased percentage of cells in G0/G1 and decreased proportion of cells in S-phase as compared to control cells. This was accompanied by up-regulation of cyclin-dependent kinase (Cdk) inhibitors p21 and decreased levels of phophorylated AKT levels. Furthermore, loss of SMS inhibited the migratory potential of Neuro 2a cells. Summary: Up-regulation of SMS under ischemic/reperfusion conditions suggests that this enzyme potentially contributes to cell cycle regulation and may contribute to maintaining neuronal cell population. Further studies may open up a new direction for identifying the molecular mechanisms of cell cycle regulation and protection following ischemic stroke

scholarly journals Separate domains of the Ran GTPase interact with different factors to regulate nuclear protein import and RNA processing.

1995 ◽  
Vol 15 (4) ◽  
pp. 2117-2124 ◽  
Author(s):  
M Ren ◽  
A Villamarin ◽  
A Shih ◽  
E Coutavas ◽  
M S Moore ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Protein Import ◽  
Nuclear Protein ◽  
Nucleotide Exchange ◽  
Cycle Progression ◽  
Ran Gtpase ◽  
Guanine Nucleotide Exchange ◽  
Nuclear Protein Import ◽  
Ran Gtp

The small Ras-related GTP binding and hydrolyzing protein Ran has been implicated in a variety of processes, including cell cycle progression, DNA synthesis, RNA processing, and nuclear-cytosolic trafficking of both RNA and proteins. Like other small GTPases, Ran appears to function as a switch: Ran-GTP and Ran-GDP levels are regulated both by guanine nucleotide exchange factors and GTPase activating proteins, and Ran-GTP and Ran-GDP interact differentially with one or more effectors. One such putative effector, Ran-binding protein 1 (RanBP1), interacts selectively with Ran-GTP. Ran proteins contain a diagnostic short, acidic, carboxyl-terminal domain, DEDDDL, which, at least in the case of human Ran, is required for its role in cell cycle regulation. We show here that this domain is required for the interaction between Ran and RanBP1 but not for the interaction between Ran and a Ran guanine nucleotide exchange factor or between Ran and a Ran GTPase activating protein. In addition, Ran lacking this carboxyl-terminal domain functions normally in an in vitro nuclear protein import assay. We also show that RanBP1 interacts with the mammalian homolog of yeast protein RNA1, a protein involved in RNA transport and processing. These results are consistent with the hypothesis that Ran functions directly in at least two pathways, one, dependent on RanBP1, that affects cell cycle progression and RNA export, and another, independent of RanBP1, that affects nuclear protein import.

scholarly journals Subcellular localization and mitotic interactome analyses identify SIRT4 as a centrosomally localized and microtubule associated protein

2020 ◽  
Author(s):  
Laura Bergmann ◽  
Alexander Lang ◽  
Christoph Bross ◽  
Simone Altinoluk-Hambüchen ◽  
Iris Fey ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Functional Roles ◽  
The Family ◽  
Spindle Apparatus ◽  
Regulation Of Cell Cycle

AbstractThe stress-inducible and senescence-associated tumor suppressor SIRT4, a member of the family of mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5), regulates bioenergetics and metabolism via NAD+-dependent enzymatic activities. Next to the known mitochondrial location, we found that a fraction of endogenous or ectopically expressed SIRT4, but not SIRT3, is located at the mitotic spindle apparatus in the cytosol. Confocal spinning disk microscopy revealed that SIRT4 localizes during the cell cycle dynamically at centrosomes with an intensity peak in G2 and early mitosis. Moreover, SIRT4 binds to microtubules and interacts with structural (α,β-tubulin, γ-tubulin, TUBGCP2, TUBGCP3) and regulatory (HDAC6) microtubule components as detected by co-immunoprecipitation and mass spectrometric analyses of the mitotic SIRT4 interactome. Overexpression of SIRT4 resulted in a pronounced decrease of acetylated α-tubulin (K40) associated with altered microtubule dynamics in mitotic cells. SIRT4 or the N-terminally truncated variant SIRT4(ΔN28), which is unable to translocate into mitochondria, delayed mitotic progression and reduced cell proliferation. This study extends the functional roles of SIRT4 beyond mitochondrial metabolism, and suggests that SIRT4 acts as a novel centrosomal / microtubule-associated protein in the regulation of cell cycle progression. Thus, stress-induced SIRT4 may exert its role as tumor suppressor through mitochondrial as well as extramitochondrial functions, the latter associated with its localization at the mitotic spindle apparatus.

scholarly journals Acetylation of Mammalian ADA3 Is Required for Its Functional Roles in Histone Acetylation and Cell Proliferation

2016 ◽  
Vol 36 (19) ◽  
pp. 2487-2502 ◽  
Author(s):  
Shakur Mohibi ◽  
Shashank Srivastava ◽  
Aditya Bele ◽  
Sameer Mirza ◽  
Hamid Band ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Histone Acetylation ◽  
Cell Cycle Progression ◽  
Site Directed Mutagenesis ◽  
Dependent Manner ◽  
Cycle Progression ◽  
Functional Roles ◽  
A Cell ◽  
Cycle Dependent

Alteration/deficiency in activation 3 (ADA3) is an essential component of specific histone acetyltransferase (HAT) complexes. We have previously shown that ADA3 is required for establishing global histone acetylation patterns and for normal cell cycle progression (S. Mohibi et al., J Biol Chem 287:29442–29456, 2012,http://dx.doi.org/10.1074/jbc.M112.378901). Here, we report that these functional roles of ADA3 require its acetylation. We show that ADA3 acetylation, which is dynamically regulated in a cell cycle-dependent manner, reflects a balance of coordinated actions of its associated HATs, GCN5, PCAF, and p300, and a new partner that we define, the deacetylase SIRT1. We use mass spectrometry and site-directed mutagenesis to identify major sites of ADA3 acetylated by GCN5 and p300. Acetylation-defective mutants are capable of interacting with HATs and other components of HAT complexes but are deficient in their ability to restore ADA3-dependent global or locus-specific histone acetylation marks and cell proliferation inAda3-deleted murine embryonic fibroblasts (MEFs). Given the key importance of ADA3-containing HAT complexes in the regulation of various biological processes, including the cell cycle, our study presents a novel mechanism to regulate the function of these complexes through dynamic ADA3 acetylation.

scholarly journals A Syx-RhoA-Dia1 signaling axis regulates cell cycle progression, DNA damage, and therapy resistance in glioblastoma

2021 ◽  
Author(s):  
Wan-Hsin Lin ◽  
Ryan W. Feathers ◽  
Lisa M. Cooper ◽  
Laura J. Lewis-Tuffin ◽  
Jann N. Sarkaria ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Cell Cycle Progression ◽  
Radiation Treatment ◽  
Therapy Resistance ◽  
Cell Cycle Regulators ◽  
Nucleotide Exchange ◽  
M Cell ◽  
Cycle Progression ◽  
Signaling Axis

AbstractGlioblastomas (GBM) are aggressive tumors that lack effective treatments. Here, we show that the Rho family guanine nucleotide exchange factor Syx promotes GBM cell growth both in vitro and in orthotopic GBM patient-derived xenografts. Growth defects upon Syx depletion are attributed to prolonged mitosis, increased DNA damage, G2/M cell cycle arrest, and cell apoptosis, mediated by altered mRNA and protein expression of various cell cycle regulators. These effects are phenocopied by depletion of the Rho downstream effector Dia1 and are due at least in part to increased cytoplasmic retention and reduced activity of the YAP/TAZ transcriptional coactivators. Further, targeting Syx signaling cooperates with radiation treatment and temozolomide (TMZ) to decrease viability in GBM cells irrespective of their inherent response to TMZ. Taken together, the data indicate that a Syx-RhoA-Dia1-YAP/TAZ signaling axis regulates cell cycle progression, DNA damage, and therapy resistance in GBM and argue for its targeting for cancer treatment.One Sentence SummarySyx promotes growth and therapy resistance in glioblastoma.

scholarly journals Subcellular Localization and Mitotic Interactome Analyses Identify SIRT4 as a Centrosomally Localized and Microtubule Associated Protein

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1950 ◽  
Author(s):  
Laura Bergmann ◽  
Alexander Lang ◽  
Christoph Bross ◽  
Simone Altinoluk-Hambüchen ◽  
Iris Fey ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Mitotic Progression ◽  
Cycle Progression ◽  
Functional Roles ◽  
The Family ◽  
Regulation Of Cell Cycle ◽  
Early Mitosis

The stress-inducible and senescence-associated tumor suppressor SIRT4, a member of the family of mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5), regulates bioenergetics and metabolism via NAD+-dependent enzymatic activities. Next to the known mitochondrial location, we found that a fraction of endogenous or ectopically expressed SIRT4, but not SIRT3, is present in the cytosol and predominantly localizes to centrosomes. Confocal spinning disk microscopy revealed that SIRT4 is found during the cell cycle dynamically at centrosomes with an intensity peak in G2 and early mitosis. Moreover, SIRT4 precipitates with microtubules and interacts with structural (α,β-tubulin, γ-tubulin, TUBGCP2, TUBGCP3) and regulatory (HDAC6) microtubule components as detected by co-immunoprecipitation and mass spectrometric analyses of the mitotic SIRT4 interactome. Overexpression of SIRT4 resulted in a pronounced decrease of acetylated α-tubulin (K40) associated with altered microtubule dynamics in mitotic cells. SIRT4 or the N-terminally truncated variant SIRT4(ΔN28), which is unable to translocate into mitochondria, delayed mitotic progression and reduced cell proliferation. This study extends the functional roles of SIRT4 beyond mitochondrial metabolism and provides the first evidence that SIRT4 acts as a novel centrosomal/microtubule-associated protein in the regulation of cell cycle progression. Thus, stress-induced SIRT4 may exert its role as tumor suppressor through mitochondrial as well as extramitochondrial functions, the latter associated with its localization at the mitotic spindle apparatus.

scholarly journals Sphingosine-1-phosphate receptor 3 influences cell cycle progression in muscle satellite cells

2013 ◽  
Vol 382 (2) ◽  
pp. 504-516 ◽  
Author(s):  
Mathieu Fortier ◽  
Nicolas Figeac ◽  
Robert B. White ◽  
Paul Knopp ◽  
Peter S. Zammit
Keyword(s):  
Cell Cycle ◽  
Satellite Cells ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Muscle Satellite Cells ◽  
Sphingosine 1 Phosphate

scholarly journals Citrus hystrix Extracts Protect Human Neuronal Cells against High Glucose-Induced Senescence

2020 ◽  
Vol 13 (10) ◽  
pp. 283
Author(s):  
Nattaporn Pattarachotanant ◽  
Tewin Tencomnao
Keyword(s):  
Cell Cycle ◽  
Western Blot ◽  
High Glucose ◽  
Cell Cycle Progression ◽  
Antioxidant Activities ◽  
Neuronal Cell ◽  
Ros Generation ◽  
Human Neuroblastoma ◽  
Cycle Progression ◽  
Cell Functions

Citrus hystrix (CH) is a beneficial plant utilized in traditional folk medicine to relieve various health ailments. The antisenescent mechanisms of CH extracts were investigated using human neuroblastoma cells (SH-SY5Y). Phytochemical contents and antioxidant activities of CH extracts were analyzed using a gas chromatograph–mass spectrometer (GC-MS), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assay. Effects of CH extracts on high glucose-induced cytotoxicity, reactive oxygen species (ROS) generation, cell cycle arrest and cell cycle-associated proteins were assessed using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) assay, non-fluorescent 2′, 7′-dichloro-dihydrofluorescein diacetate (H2DCFDA) assay, flow cytometer and Western blot. The extracts protected neuronal senescence by inhibiting ROS generation. CH extracts induced cell cycle progression by releasing senescent cells from the G1 phase arrest. As the Western blot confirmed, the mechanism involved in cell cycle progression was associated with the downregulation of cyclin D1, phospho-cell division cycle 2 (pcdc2) and phospho-Retinoblastoma (pRb) proteins. Furthermore, the Western blot showed that extracts increased Surtuin 1 (SIRT1) expression by increasing the phosphorylation of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Collectively, CH extracts could protect high glucose-induced human neuronal senescence by inducing cell cycle progression and up-regulation of SIRT1, thus leading to the improvement of the neuronal cell functions.

Sign in / Sign up

Export Citation Format

Share Document