A Novel Guanine Nucleotide Exchange Factor, MYOGEF, is Required for Cytokinesis

Wu, Di; Asiedu, Michael K.; Adelstein, Robert S.; Wei, Qize

doi:10.4161/cc.5.11.2815

Cited by 44 publications

(75 citation statements)

References 31 publications

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“…The results of immunofluorescence staining, as well as of Ect2 knockdown experiments, provided the first evidence strongly suggesting that Ect2 is dispensable and that a substitute GEF can mediate activation of RhoA to form a contractile ring in certain types of mammalian cells, including HT1080 cells. VAV3 (Fujikawa et al, 2002), MyoGEF (Wu et al, 2006), and GEF-H1 (Birkenfeld et al, 2007) are other GEFs reportedly involved in activation of RhoA during cytokinesis. Thus, one of these GEFs might play a major role to form a contractile ring in HT1080 cells.…”

Section: Different Roles Of Ect2 During Different Phases Of Cytokinesmentioning

confidence: 99%

Novel Functions of Ect2 in Polar Lamellipodia Formation and Polarity Maintenance during “Contractile Ring-Independent” Cytokinesis in Adherent Cells

Kanada

Nagasaki

Uyeda

2008

MBoC

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Some mammalian cells are able to divide via both the classic contractile ring-dependent method (cytokinesis A) and a contractile ring-independent, adhesion-dependent method (cytokinesis B). Cytokinesis A is triggered by RhoA, which, in HeLa cells, is activated by the guanine nucleotide-exchange factor Ect2 localized at the central spindle and equatorial cortex. Here, we show that in HT1080 cells undergoing cytokinesis A, Ect2 does not localize in the equatorial cortex, though RhoA accumulates there. Moreover, Ect2 depletion resulted in only modest multinucleation of HT1080 cells, enabling us to establish cell lines in which Ect2 was constitutively depleted. Thus, RhoA is activated via an Ect2-independent pathway during cytokinesis A in HT1080 cells. During cytokinesis B, Ect2-depleted cells showed narrower accumulation of RhoA at the equatorial cortex, accompanied by compromised pole-to-equator polarity, formation of ectopic lamellipodia in regions where RhoA normally would be distributed, and delayed formation of polar lamellipodia. Furthermore, C3 exoenzyme inhibited equatorial RhoA activation and polar lamellipodia formation. Conversely, expression of dominant active Ect2 in interphase HT1080 cells enhanced RhoA activity and suppressed lamellipodia formation. These results suggest that equatorial Ect2 locally suppresses lamellipodia formation via RhoA activation, which indirectly contributes to restricting lamellipodia formation to polar regions during cytokinesis B. INTRODUCTIONThe final step in the process of cell division is cytokinesis, during which the cellular contents are divided and the two daughter cells are formed. Formation of the furrow that ultimately leads to separation of the two daughter cells is mediated in large part by RhoA (Kishi et al., 1993;Mabuchi et al., 1993;Jantsch-Plunger et al., 2000), one of the Rho-type small GTPases, which also include Rac1 and Cdc42; these mediators regulate actin dynamics during a variety of cellular events (reviewed by Etienne-Manneville and Hall, 2002). In the classic "purse string" model of cytokinesis, actomyosin-dependent contraction of the contractile ring drives cleavage of the equatorial region (reviewed by Glotzer, 2005). RhoA-dependent stimulation of actin polymerization through regulation of formins is crucial to formation of the contractile ring (Sagot et al., 2002;Kovar et al., 2003), while phosphorylation of myosin light chain by Rhoassociated kinase (ROCK) leads to myosin activation and contraction of the ring (Amano et al., 1996;Kimura et al., 1996;Piekny and Mains, 2002;Matsumura, 2005).Rho GTPases are activated by guanine nucleotide exchange factors (GEFs). Among the numerous GEFs that have been identified, Ect2 (Epithelial cell transforming protein 2) has been shown to play a key role in cytokinesis. Ect2 was originally identified as a transforming protein in an expression-cloning assay (Miki et al., 1993). Its role in cytokinesis was first identified in studies of Drosophila melanogaster. The Drosophila and Caenorhabditis elegans orthologue...

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Section: Different Roles Of Ect2 During Different Phases Of Cytokinesmentioning

confidence: 99%

Novel Functions of Ect2 in Polar Lamellipodia Formation and Polarity Maintenance during “Contractile Ring-Independent” Cytokinesis in Adherent Cells

Kanada

Nagasaki

Uyeda

2008

MBoC

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“…Plasmids and Cell Culture-pEGFP-MyoGEF and pCS3-MyoGEF were described previously (27). GIPC1 and MyoGEF cDNA fragments were subcloned into pEGFP-C3 and pCS3ϩMT vectors to generate plasmids encoding GFP-or Myc-tagged polypeptides.…”

Section: Methodsmentioning

confidence: 99%

“…Immunoprecipitation and GST Pulldown Assays-Immunoprecipitation and GST pulldown assays were carried out as described previously (27,28). Briefly, transfected cells were lysed in radioimmune precipitation assay lysis buffer (50 mM Tris-HCl (pH 7.5), 150 mM NaCl, 0.25% deoxycholate, 1% Nonidet P-40, 1 mM EDTA, 1 mM PMSF, 1 mM Na 3 VO 4 , and 1 mM NaF with protease inhibitor mixture) for 10 min on ice.…”

Section: Methodsmentioning

confidence: 99%

“…The following primary antibodies were used: mouse anti-Myc (9E10, 1:1000), rabbit anti-GFP (1:1000), and rabbit anti-␤-tubulin (1:2000) (Santa Cruz Biotechnology); goat anti-GIPC1 (1:250; Novus Biologicals, Littleton, CO); and rabbit anti-MyoGEF (1:100) (25,27). The blots were washed and incubated with horseradish peroxide-conjugated secondary antibodies (1:5000; Santa Cruz Biotechnology) for 1 h at 23°C.…”

Section: Methodsmentioning

confidence: 99%

“…MyoGEF-We reported previously that MyoGEF is involved in the regulation of cytokinesis and breast cancer cell invasion (25)(26)(27). Yeast two-hybrid screening led us to identify GIPC1 as an interacting partner of MyoGEF.…”

Section: Gipc1 Pdz Domain Is Required For Interactions Withmentioning

confidence: 99%

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GIPC1 Interacts with MyoGEF and Promotes MDA-MB-231 Breast Cancer Cell Invasion

Haruta

Wei

2010

Journal of Biological Chemistry

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The Expression Pattern of the Phosphoproteome Is Significantly Changed During the Growth Phases of Recombinant CHO Cell Culture

Kaushik

Henry

Clynes

et al. 2018

Biotechnology Journal

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Post-translational modification of proteins by reversible phosphorylation plays a pivotal role in regulating key cellular processes including transcription, translation, cell proliferation, differentiation, apoptosis, and signal transduction. Despite the importance of the phosphorylation level of regulation, little work has been carried out on the phosphoproteomic characterization of Chinese hamster ovary (CHO) cells in bioprocess-relevant conditions. Growth control strategies are often used to prolong culture duration and increase specific productivity; however, the cellular mechanisms and regulatory pathways underlying growth strategies are poorly understood in CHO cells. Phosphorylation changes are dynamic and will respond to changes in culture conditions; this may reflect the status of the cells with respect to growth and viability of the culture. Herein, this study uses a phosphopeptide enrichment strategy in conjunction with LC-MS/MS to carry out a large-scale differential phosphoproteomic analysis of IgG producing CHO DP12 cells at various phases of growth in serum-free suspension batch culture to characterize dynamic changes to the phosphoproteome with changing culture conditions. In total over the various growth phases, 3777 differentially expressed unique phosphopeptides are identified from 1415 differentially expressed unique phosphoproteins. Analysis of the whole cell lysate without phosphopeptide enrichment over the various growth phases revealed the differential expression of 834 unique proteins, with an overlap of 188 proteins between the proteomic and phosphoproteomic analyses. The inclusion of phosphoproteomic data significantly improves proteome coverage but also gives insights into the post-translational level of regulation during cellular growth of recombinant CHO cells.

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A Novel Guanine Nucleotide Exchange Factor, MYOGEF, is Required for Cytokinesis

Cited by 44 publications

References 31 publications

Novel Functions of Ect2 in Polar Lamellipodia Formation and Polarity Maintenance during “Contractile Ring-Independent” Cytokinesis in Adherent Cells

Novel Functions of Ect2 in Polar Lamellipodia Formation and Polarity Maintenance during “Contractile Ring-Independent” Cytokinesis in Adherent Cells

GIPC1 Interacts with MyoGEF and Promotes MDA-MB-231 Breast Cancer Cell Invasion

The Expression Pattern of the Phosphoproteome Is Significantly Changed During the Growth Phases of Recombinant CHO Cell Culture

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