scholarly journals CLIC4 and CLIC1 bridge plasma membrane and cortical actin network for a successful cytokinesis

2019 ◽  
Vol 3 (2) ◽  
pp. e201900558 ◽  
Author(s):  
Zeynep Cansu Uretmen Kagiali ◽  
Nazan Saner ◽  
Mehmet Akdag ◽  
Erdem Sanal ◽  
Beste Senem Degirmenci ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Mammalian Cells ◽  
Transferase Activity ◽  
Cleavage Furrow ◽  
Dependent Manner ◽  
Glutathione S Transferase ◽  
Cortical Actin ◽  
Multinucleated Cells ◽  
Glutathione S Transferases ◽  
Cycle Dependent

CLIC4 and CLIC1 are members of the well-conserved chloride intracellular channel proteins (CLICs) structurally related to glutathione-S-transferases. Here, we report new roles of CLICs in cytokinesis. At the onset of cytokinesis, CLIC4 accumulates at the cleavage furrow and later localizes to the midbody in a RhoA-dependent manner. The cell cycle–dependent localization of CLIC4 is abolished when its glutathione S-transferase activity–related residues (C35A and F37D) are mutated. Ezrin, anillin, and ALIX are identified as interaction partners of CLIC4 at the cleavage furrow and midbody. Strikingly, CLIC4 facilitates the activation of ezrin at the cleavage furrow and reciprocally inhibition of ezrin activation diminishes the translocation of CLIC4 to the cleavage furrow. Furthermore, knockouts of CLIC4and CLIC1 cause abnormal blebbing at the polar cortex and regression of the cleavage furrow at late cytokinesis leading to multinucleated cells. We conclude that CLIC4 and CLIC1 function together with ezrin where they bridge plasma membrane and actin cytoskeleton at the polar cortex and cleavage furrow to promote cortical stability and successful completion of cytokinesis in mammalian cells.

scholarly journals E2F activity is regulated by cell cycle-dependent changes in subcellular localization.

1997 ◽  
Vol 17 (12) ◽  
pp. 7268-7282 ◽  
Author(s):  
R Verona ◽  
K Moberg ◽  
S Estes ◽  
M Starz ◽  
J P Vernon ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Subcellular Localization ◽  
Nuclear Localization ◽  
Mammalian Cells ◽  
Critical Role ◽  
Biological Properties ◽  
Dependent Manner ◽  
Restriction Point ◽  
Cycle Dependent ◽  
Almost All

E2F directs the cell cycle-dependent expression of genes that induce or regulate the cell division process. In mammalian cells, this transcriptional activity arises from the combined properties of multiple E2F-DP heterodimers. In this study, we show that the transcriptional potential of individual E2F species is dependent upon their nuclear localization. This is a constitutive property of E2F-1, -2, and -3, whereas the nuclear localization of E2F-4 is dependent upon its association with other nuclear factors. We previously showed that E2F-4 accounts for the majority of endogenous E2F species. We now show that the subcellular localization of E2F-4 is regulated in a cell cycle-dependent manner that results in the differential compartmentalization of the various E2F complexes. Consequently, in cycling cells, the majority of the p107-E2F, p130-E2F, and free E2F complexes remain in the cytoplasm. In contrast, almost all of the nuclear E2F activity is generated by pRB-E2F. This complex is present at high levels during G1 but disappears once the cells have passed the restriction point. Surprisingly, dissociation of this complex causes little increase in the levels of nuclear free E2F activity. This observation suggests that the repressive properties of the pRB-E2F complex play a critical role in establishing the temporal regulation of E2F-responsive genes. How the differential subcellular localization of pRB, p107, and p130 contributes to their different biological properties is also discussed.

scholarly journals The presence and longitudinal distribution of the glutathione S-transferase in rat epididymis and vas deferens

1980 ◽  
Vol 189 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Barbara F. Hales ◽  
Christiane Hachey ◽  
Bernard Robaire
Keyword(s):  
Substrate Specificity ◽  
Isoelectric Focusing ◽  
Vas Deferens ◽  
Longitudinal Distribution ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Potential Significance ◽  
Glutathione S Transferases ◽  
Rat Epididymis ◽  
First Time

The presence of the glutathione S-transferases, enzymes that catalyse the conjugation of glutathione with a variety of compounds, is reported here, for the first time, in the mammalian epididymis–vas deferens. These glutathione S-transferases, approx. 50% of those from rat liver on a per-mg-of-protein basis, are resolved by isoelectric focusing into six peaks, each with a characteristic isoelectric point and substrate specificity. By these same criteria, the first three peaks (pI 8.9, 8.2 and 7.8) can be identified as transferases B, A and C respectively. The fifth peak (pI7.2) may correspond to transferase M; the fourth (pI7.5) and sixth (pI7.0) peaks do not correspond to previously described transferases. The distribution of transferase activity towards any one substrate studied differs in sequential sections of the epididymis and vas deferens; in addition, the longitudinal-distribution pattern differs for each of the three substrates studied. Isoelectric focusing of the cytosol fractions of the different sections further substantiates these observations. The potential significance of these enzymes and of their distribution in terms of epididymal function, maturation of spermatozoa, is discussed.

scholarly journals Inhibition of Cyclin-dependent Kinase 1 Induces Cytokinesis without Chromosome Segregation in an ECT2 and MgcRacGAP-dependent Manner

2005 ◽  
Vol 280 (43) ◽  
pp. 36502-36509 ◽  
Author(s):  
Fumihiko Niiya ◽  
Xiaozhen Xie ◽  
Kyung S. Lee ◽  
Hiroki Inoue ◽  
Toru Miki
Keyword(s):  
Rna Interference ◽  
Mammalian Cells ◽  
Specific Inhibitor ◽  
Small Gtpase ◽  
Dominant Negative ◽  
Cleavage Furrow ◽  
Dependent Manner ◽  
Cyclin Dependent Kinase ◽  
Mitotic Spindles ◽  
Initiation Mechanism

Cleavage furrow formation marks the onset of cell division during early anaphase. The small GTPase RhoA and its regulators ECT2 and MgcRacGAP have been implicated in furrow ingression in mammalian cells, but the signaling upstream of these molecules remains unclear. We now show that the inhibition of cyclin-dependent kinase (Cdk)1 is sufficient to initiate cytokinesis. When mitotically synchronized cells were treated with the Cdk-specific inhibitor BMI-1026, the initiation of cytokinesis was induced precociously before chromosomal separation. Cytokinesis was also induced by the Cdk1-specific inhibitor purvalanol A but not by Cdk2/Cdk5- or Cdk4-specific inhibitors. Consistent with initiation of precocious cytokinesis by Cdk1 inhibition, introduction of anti-Cdk1 monoclonal antibody resulted in cells with aberrant nuclei. Depolymerization of mitotic spindles by nocodazole inhibited BMI-1026-induced precocious cytokinesis. However, in the presence of a low concentration of nocodazole, BMI-1026 induced excessive membrane blebbing, which appeared to be caused by formation of ectopic cleavage furrows. Depletion of ECT2 or MgcRacGAP by RNA interference abolished both of the phenotypes (precocious furrowing after nocodazole release and excessive blebbing in the presence of nocodazole). RNA interference of RhoA or expression of dominant-negative RhoA efficiently reduced both phenotypes. RhoA was localized at the cleavage furrow or at the necks of blebs. We propose that Cdk1 inactivation is sufficient to activate a signaling pathway leading to cytokinesis, which emanates from mitotic spindles and is regulated by ECT2, MgcRacGAP, and RhoA. Chemical induction of cytokinesis will be a valuable tool to study the initiation mechanism of cytokinesis.

Effect of inhibitors of glutathione S-transferase on glyceryl trinitrate activity in isolated rat aorta

1993 ◽  
Vol 71 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Rita Nigam ◽  
Tracy Whiting ◽  
Brian M. Bennett
Keyword(s):  
Glyceryl Trinitrate ◽  
Cyclic Gmp ◽  
Guanylyl Cyclase ◽  
Rat Aorta ◽  
Supernatant Fraction ◽  
Organic Nitrates ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Glutathione S Transferases

We investigated the role of glutathione S-transferases (enzymes known to biotransform organic nitrates) in the vascular action of glyceryl trinitrate (GTN). Relaxation of phenylephrine-contracted rat aortic strips was assessed in the presence or absence of the glutathione S-transferase inhibitors Basilen Blue, bromosulfophthalein, Rose Bengal, hematin, chlorotriphenyltin, and (octyloxy)benzoylvinylglutathione. Whereas none of the inhibitors increased the EC50 for GTN relaxation, glutathione S-transferase activity in the 100 000 × g supernatant fraction of rat aorta was inhibited markedly by most of the inhibitors. In addition, GTN-stimulated activation of aortic guanylyl cyclase in broken-cell preparations was attenuated by all of the glutathione S-transferase inhibitors, suggesting a direct inhibitory action on guanylyl cyclase. In other experiments using aortic strips preexposed to phenylephrine, the inhibitors had no effect on GTN-induced cyclic GMP accumulation or on vascular biotransformation of GTN. In contrast, both Basilen Blue and bromosulfophthalein significantly inhibited GTN-induced relaxation of K+-contracted aortic strips, and Basilen Blue significantly inhibited GTN biotransformation in aortic strips preexposed to 25 mM K+. This may be due to a more favourable electrochemical gradient for entry of the inhibitors into membrane-depolarized tissues. We conclude that vascular glutathione S-transferases play a role in mediating the vasodilator actions of GTN in intact tissues in vitro, but that this appears to depend upon the nature of the contractile agent used in such studies.Key words: glyceryl trinitrate, glutathione S-transferase, cyclic GMP, vascular smooth muscle, biotransformation.

scholarly journals The TRE17 Oncogene Encodes a Component of a Novel Effector Pathway for Rho GTPases Cdc42 and Rac1 and Stimulates Actin Remodeling

2003 ◽  
Vol 23 (6) ◽  
pp. 2151-2161 ◽  
Author(s):  
Jeffrey M. Masuda-Robens ◽  
Sara N. Kutney ◽  
Hongwei Qi ◽  
Margaret M. Chou
Keyword(s):  
Plasma Membrane ◽  
Rho Gtpases ◽  
Actin Polymerization ◽  
Dependent Manner ◽  
Cortical Actin ◽  
Actin Remodeling ◽  
Membrane Recruitment ◽  
Truncation Mutant ◽  
Effector Pathway

ABSTRACT The Rho family GTPases Cdc42 and Rac1 play fundamental roles in transformation and actin remodeling. Here, we demonstrate that the TRE17 oncogene encodes a component of a novel effector pathway for these GTPases. TRE17 coprecipitated specifically with the active forms of Cdc42 and Rac1 in vivo. Furthermore, the subcellular localization of TRE17 was dramatically regulated by these GTPases and mitogens. Under serum-starved conditions, TRE17 localized predominantly to filamentous structures within the cell. Epidermal growth factor (EGF) induced relocalization of TRE17 to the plasma membrane in a Cdc42-/Rac1-dependent manner. Coexpression of activated alleles of Cdc42 or Rac1 also caused complete redistribution of TRE17 to the plasma membrane, where it partially colocalized with the GTPases in filopodia and ruffles, respectively. Membrane recruitment of TRE17 by EGF or the GTPases was dependent on actin polymerization. Finally, we found that a C-terminal truncation mutant of TRE17 induced the accumulation of cortical actin, mimicking the effects of activated Cdc42. Together, these results identify TRE17 as part of a novel effector complex for Cdc42 and Rac1, potentially contributing to their effects on actin remodeling. The present study provides insights into the regulation and cellular function of this previously uncharacterized oncogene.

scholarly journals Codon bias determines sorting of ion channel protein

2020 ◽  
Author(s):  
Marina Kithil ◽  
Anja Jeannine Engel ◽  
Markus Langhans ◽  
Oliver Rauh ◽  
Matea Cartolano ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Secretory Pathway ◽  
Model Systems ◽  
Dependent Manner ◽  
Intracellular Proteins ◽  
Polypeptide Folding ◽  
A Cell ◽  
Identical Amino Acid Sequence ◽  
Cycle Dependent ◽  
The Impact

AbstractThe choice of codons can influence local translation kinetics during protein synthesis. The question of whether the modulation of polypeptide folding and binding to chaperons influences sorting of nascent membrane proteins remains unclear. Here, we use two similar K+ channels as model systems to examine the impact of codon choice on protein sorting. By monitoring transient expression of GFP tagged proteins in mammalian cells we find that targeting of one channel to the secretory pathway is insensitive to codon optimization. In contrast, sorting of the second channel to the mitochondria is very sensitive to codon choice. The protein with an identical amino acid sequence is sorted in a codon and cell cycle dependent manner either to mitochondria or the secretory pathway. The data establish that a gene with either rare or frequent codons serves together with a cell-state depending decoding mechanism as a secondary code for sorting intracellular proteins.

scholarly journals Comparison of renal and hepatic glutathione S-transferases in the rat

1976 ◽  
Vol 158 (2) ◽  
pp. 243-248 ◽  
Author(s):  
N Kaplowitz ◽  
G Clifton ◽  
J Kuhlenkamp ◽  
J D Wallin
Keyword(s):  
Organic Anion ◽  
Gel Filtration ◽  
Competitive Inhibitor ◽  
Transferase Activity ◽  
Close Correspondence ◽  
Glutathione S Transferase ◽  
Competitive Inhibitors ◽  
Liver And Kidney ◽  
Glutathione S Transferases

Renal and hepatic GSH (reduced glutathione) S-transferase were compared with respect to substrate and inhibitory kinetics and hormonal influences in vivo. An example of each of five classes of substrates (aryl, aralkyl, epoxide, alkyl and alkene) was used. In the gel filtration of renal or hepatic cytosol, an identical elution volume was found for all the transferase activities. Close correspondence in Km values was found for aryl, epoxide- and alkyl-transferase activities, with only the aralkyl activity significantly lower in kidney. Probenecid and p-aminohippurate were competitive inhibitors of renal aryl-, aralkyl-, epoxide- and alkyl-transferase activities and inhibited renal alkene activity. Close correspondence in Ki values for inhibition by probenecid of these activities in kidney and liver was found. In addition, furosemide was a potent competitive inhibitor of renal alkyl-transferase activity. Hypophysectomy resulted in significant increases in aryl-, araklyl-, and expoxide-transferase activities in liver and kidney. The hypophysectomy-induced increases in renal aryl- and aralkyl-transferase activities (approx. 100%) were more than twofold greater than increases in hepatic activities (approx. 40%). Administration of thyroxine prevented the hypophysectomy-induced increase in aryltransferase activity in both kidney and liver. The renal GSH S-transferases, in view of similarities to the hepatic activities, may play a role as cytoplasmic organic-anion receptors, as previously proposed for the hepatic enzymes.

scholarly journals Fragile X–Related Protein 1 Regulates Nucleoporin Localization in a Cell Cycle–Dependent Manner

2021 ◽  
Vol 9 ◽  
Author(s):  
Arantxa Agote-Arán ◽  
Junyan Lin ◽  
Izabela Sumara
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Fragile X ◽  
Protein Translation ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Dependent Manner ◽  
Independent Manner ◽  
Cycle Dependent

Nuclear pore complexes (NPCs) are embedded in the nuclear envelope (NE) where they ensure the transport of macromolecules between the nucleus and the cytoplasm. NPCs are built from nucleoporins (Nups) through a sequential assembly order taking place at two different stages during the cell cycle of mammalian cells: at the end of mitosis and during interphase. In addition, fragile X–related proteins (FXRPs) can interact with several cytoplasmic Nups and facilitate their localization to the NE during interphase likely through a microtubule-dependent mechanism. In the absence of FXRPs or microtubule-based transport, Nups aberrantly localize to the cytoplasm forming the so-called cytoplasmic nucleoporin granules (CNGs), compromising NPCs’ function on protein export. However, it remains unknown if Nup synthesis or degradation mechanisms are linked to the FXRP–Nup pathway and if and how the action of FXRPs on Nups is coordinated with the cell cycle progression. Here, we show that Nup localization defects observed in the absence of FXR1 are independent of active protein translation. CNGs are cleared in an autophagy- and proteasome-independent manner, and their presence is restricted to the early G1 phase of the cell cycle. Our results thus suggest that a pool of cytoplasmic Nups exists that contributes to the NPC assembly specifically during early G1 to ensure NPC homeostasis at a short transition from mitosis to the onset of interphase.

Tissue Distribution and Properties of Glutathione S-transferases in Micromelalopha troglodyta (Lepidoptera: Notodontidae)

2008 ◽  
Vol 43 (3) ◽  
pp. 268-278 ◽  
Author(s):  
Fang Tang ◽  
Xiu-Bo Zhang ◽  
Yu-Sheng Liu ◽  
Xi-Wu Gao
Keyword(s):  
Tissue Distribution ◽  
Tannic Acid ◽  
Fat Body ◽  
Inhibitory Effect ◽  
Transferase Activity ◽  
Glutathione S Transferase ◽  
Important Pest ◽  
Glutathione S Transferases ◽  
Gst Activity ◽  
Different Tissues

The small prominent, Micromelalopha troglodyta (Graeser) (Lepidoptera: Notodontidae), is an important pest of poplar in China. Glutathione S-transferases are known to be responsible for adaptation mechanisms of M. troglodyta. Thus, the tissue distribution and kinetic constants of glutathione S-transferase activity in the small prominent were studied. Significant differences in glutathione S-transferase (GST) activity and distribution percentages of GST activity and kinetic characteristics were observed among 4 tissues (head, midgut, fat body and integument). Furthermore, the inhibition of glutathione S-transferase activity in 4 tissues by 21 inhibitors was conducted. The results showed the inhibition of GST activity of different tissues by 21 inhibitors is different. For GST activity in heads, chlorpyrifos, profenofos, lambda-cyhalothrin, fipronil and quercetin were the best inhibitors tested. Tannic acid was the most potent inhibitor of midgut GST activity. In the fat body, GST activity was inhibited most by tannic acid, chlorpyrifos and profenofos. The inhibitory effect of profenofos and phoxim was highest for GST activity in the integument. Our results showed that glutathione S-transferases in different tissues are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.

scholarly journals Cell cycle dependent changes in the plasma membrane organization of mammalian cells

2017 ◽  
Vol 1859 (3) ◽  
pp. 350-359 ◽  
Author(s):  
Manuela Denz ◽  
Salvatore Chiantia ◽  
Andreas Herrmann ◽  
Peter Mueller ◽  
Thomas Korte ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Plasma Membrane ◽  
Mammalian Cells ◽  
Membrane Organization ◽  
Cycle Dependent
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