Sequential functioning of the ECT-2 RhoGEF, RHO-1 and CDC-42 establishes cell polarity in Caenorhabditis elegans embryos

Motegi, Fumio; Sugimoto, Akihiro

doi:10.1038/ncb1459

Cited by 173 publications

(262 citation statements)

References 28 publications

Supporting

Mentioning

232

Contrasting

Order By: Relevance

“…4B). ECT-2 and RHO-1 have been reported to segregate to the anterior with polarity onset (11). Our data show that, as the cortex polarizes, YFP-RGA-3, YFP-ECT-2, and YFP-RHO-1 segregate to the anterior [Fig.…”

Section: Rga-3 Is a Cortical Protein That Segregates To The Anterior supporting

confidence: 52%

“…4B, YFP-RGA-3 (n ϭ 17), YFP-RHO-1 (n ϭ 3), YFP-ECT-2 (n ϭ 20), and SI . It has been proposed that anterior segregation of RHO-1 and ECT-2 acts to keep the contractile activity of the anterior cortex high during polarity establishment (11). We show that, during polarity establishment, both positive and negative regulators of RHO-1 segregate to the anterior.…”

Section: Rga-3 Is a Cortical Protein That Segregates To The Anterior mentioning

confidence: 55%

“…If the acto-myosin network is globally disrupted, symmetry is not broken and the anterior PAR complex does not segregate into an anterior domain (7)(8)(9)(10)(11)(12)(13)(14). How does the actomyosin cytoskeleton regulate the size of the PAR domains?…”

mentioning

confidence: 99%

“…Guanine nucleotide exchange factors (GEF) catalyze the exchange of the GDP for a new GTP molecule, thus reactivating the GTPase. In C. elegans RNAi of rho-1 or its GEF ect-2 abolishes cortical contractility and disrupts the organization of the acto-myosin cytoskeleton (10)(11)(12). As a consequence, anterior and posterior PAR domains can overlap.…”

mentioning

confidence: 99%

See 3 more Smart Citations

The Rho GTPase-activating proteins RGA-3 and RGA-4 are required to set the initial size of PAR domains in Caenorhabditis elegans one-cell embryos

Schonegg

Constantinescu

Hoege

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

115

129

View full text Add to dashboard Cite

Caenorhabditis elegans embryos establish cortical domains of PAR proteins of reproducible size before asymmetric cell division. The ways in which the size of these domains is set remain unknown. Here we identify the GTPase-activating proteins (GAPs) RGA-3 and RGA-4, which regulate the activity of the small GTPase RHO-1. rga-3/4(RNAi) embryos have a hypercontractile cortex, and the initial relative size of their anterior and posterior PAR domains is altered. Thus, RHO-1 activity appears to control the level of cortical contractility and concomitantly the size of cortical domains. These data support the idea that in C. elegans embryos the initial size of the PAR domains is set by regulating the contractile activity of the acto-myosin cytoskeleton through the activity of RHO-1. RGA-3/4 have functions different from CYK-4, the other known GAP required for the first cell division, showing that different GAPs cooperate to control the activity of the acto-myosin cytoskeleton in the first cell division of C. elegans embryos.cell polarity ͉ cortex ͉ NMY-2 ͉ contractility C ell polarization allows a spatial differentiation of cellular functions. For instance, cells polarize to migrate toward a signal, to secrete molecules in a biased direction, and to divide asymmetrically to generate different daughter cells. Polarity establishment depends on the segregation of the cell cortex into different cortical domains, which then dictate asymmetric functions within the cytoplasm. The formation of cortical domains involves two interlinked problems: How does a cell initially set the size of its domains, and how is the size of the domains maintained during asymmetric functioning? Recent work in a number of organisms has identified many of the components of these cortical domains (1-4). However, it remains unclear how these components determine the size of the domains. How can the collective activity of molecules determine the size of a domain that might be several orders of magnitude larger than the molecules themselves?The formation of polarity in Caenorhabditis elegans embryos is an excellent system to study the establishment of cortical domains. The polarization of the cortex is marked by the formation of PAR protein domains: An anterior domain comprising PAR-3, PAR-6, and atypical PKC (PKC-3), together with the Rho GTPase CDC-42; and a posterior domain comprising PAR-1 and PAR-2. After meiosis, the members of the anterior PAR complex are localized all over the cortex. When symmetry is broken by the centrosome, the anterior complex retracts toward the anterior of the embryo. Concomitantly, the posterior PAR complex fills in the cortical area left by the retraction of the anterior PAR complex, thereby establishing the polarity of a one-cell embryo (5, 6). During the subsequent maintenance phase, the two PAR domains have consistent sizes {a variation of Ϸ2% between embryos [unpublished data and supporting information (SI) Text]} until cytokinesis. These cortical domains control the asymmetric localization of cell fate determinants a...

show abstract

Section: Rga-3 Is a Cortical Protein That Segregates To The Anterior supporting

confidence: 52%

Section: Rga-3 Is a Cortical Protein That Segregates To The Anterior mentioning

confidence: 55%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

The Rho GTPase-activating proteins RGA-3 and RGA-4 are required to set the initial size of PAR domains in Caenorhabditis elegans one-cell embryos

Schonegg

Constantinescu

Hoege

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

115

129

View full text Add to dashboard Cite

show abstract

“…Cortical contact by the sp/centrosome results in localized inactivation of the RHO-1 guanine nucleotide-exchange factor ECT-2, and suppression of myosin contractility radiating from the site of contact (Motegi and Sugimoto, 2006;Schonegg and Hyman, 2006). Sperm also provides the Rho GTPase activating protein, CYK-4, which may contribute to RHO-1 inactivation (Jenkins et al, 2006).…”

Section: Ap Polarizationmentioning

confidence: 99%

The eggshell in the C. elegans oocyte‐to‐embryo transition

Johnston

Dennis

2011

Genesis

View full text Add to dashboard Cite

Summary: In egg-laying animals, embryonic development takes place within the highly specialized environment provided by the eggshell and its underlying extracellular matrix. Far from being simply a passive physical support, the eggshell is a key player in many early developmental events. Herein, we review current understanding of eggshell structure, biosynthesis, and function in zygotic development of the nematode, C. elegans. Beginning at sperm contact or entry, eggshell layers are produced sequentially. The earlier outer layers are required for secretion or organization of inner layers, and layers differ in composition and function. Developmental events that depend on the eggshell include polyspermy barrier generation, high fidelity meiotic chromosome segregation, osmotic barrier synthesis, polar body extrusion, anterior-posterior polarization, and organization of membrane and cortical proteins. The C. elegans eggshell is proving to be an excellent, tractable system to study the molecular cues of the extracellular matrix that instruct cell polarity and early development. genesis 50:333-349, 2012. V V C 2011 Wiley Periodicals, Inc.

show abstract

Caenorhabditis elegansEmbryo: Establishment of Asymmetry

Espiritu

Rose

2013

Encyclopedia of Life Sciences

View full text Add to dashboard Cite

In Caenorhabditis elegans , asymmetry is established in the one‐cell embryo in response to the position of the sperm provided centrosome. Asymmetric contraction of actin and myosin at the cortex leads to the localisation of the conserved PAR (partitioning defective) polarity proteins into anterior and posterior cortical domains. The PAR proteins and associated protein kinases generate cytoplasmic gradients of polarity mediators, which in turn regulate the anterior/posterior cytoplasmic localisation of downstream cell fate regulators. The PAR proteins also regulate a conserved G protein pathway that coordinates the division plane with the anterior/posterior axis. Thus, the first division is asymmetric and the daughter cells have different developmental fates. During the next few divisions, anterior/posterior asymmetries and cell–cell signalling events establish the dorsal/ventral and left–right axes of the embryo and further refine cell fates. Key Concepts: The C. elegans embryo exhibits an invariant pattern of asymmetric cell divisions that generates diverse cell types. Asymmetric divisions are regulated by the conserved PAR proteins, which become localised in anterior and posterior cortical domains during polarity establishment after fertilisation. Polarity establishment occurs in response to an unknown cue associated with the sperm centrosome, which causes an actomyosin cortical flow that localises the anterior PAR proteins. PAR polarity cues create a cytoplasmic gradient of the polarity mediators MEX‐5 and MEX‐6, which act together with other polarity mediators to generate the asymmetric localisation of cell fate determinants. Asymmetric localisation of cell fate determinants is accomplished mainly through protein degradation and translational regulation. The localisation of cell fate determinants combined with cell–cell signalling events leads to specification of different developmental programmes in cells of the early embryo. A conserved G protein pathway functions with the microtubule motor dynein to position the mitotic spindle on the polarity axis during asymmetric divisions.

show abstract

Sequential functioning of the ECT-2 RhoGEF, RHO-1 and CDC-42 establishes cell polarity in Caenorhabditis elegans embryos

Cited by 173 publications

References 28 publications

The Rho GTPase-activating proteins RGA-3 and RGA-4 are required to set the initial size of PAR domains in Caenorhabditis elegans one-cell embryos

The Rho GTPase-activating proteins RGA-3 and RGA-4 are required to set the initial size of PAR domains in Caenorhabditis elegans one-cell embryos

The eggshell in the C. elegans oocyte‐to‐embryo transition

Caenorhabditis elegansEmbryo: Establishment of Asymmetry

Contact Info

Product

Resources

About