Bud3 activates Cdc42 to establish a proper growth site in budding yeast

Kang, Pil Jung; Lee, Mid Eum; Park, Hay-Oak

doi:10.1083/jcb.201402040

Cited by 42 publications

(108 citation statements)

References 57 publications

(87 reference statements)

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“…Previous studies indicate that the G1 phase is partitioned into two steps, T1 and T2, by the exit of the transcriptional repressor Whi5 from the nucleus (Di Talia et al, 2007) and that the stepwise activation of Cdc42 correlates with this G1 partitioning (Kang et al, 2014). We thus asked whether the distinct Cdc42 polarization dynamics in daughter cells is temporally correlated with the G1 partitioning.…”

Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

“…Rga1 inhibits polarization of Cdc42 within the division site and thus prevents re-budding at the same bud site (Tong et al, 2007). Our recent study suggests that Cdc42 is activated in two steps in the G1 phase in haploid cells, first by Bud3 and then by Cdc24 (Kang et al, 2014). This stepwise activation of Cdc42 is likely to be important for linking the axial landmark to the establishment of polarity.…”

Section: Introductionmentioning

confidence: 99%

“…Activation of Cdc42 by Bud3 is likely to be crucial for axial budding (Kang et al, 2014); however, it remains unclear how a single site of Cdc42 polarization is determined because Bud3 and other axial landmark proteins localize to the division site as a homogeneous ring (Fig. 1A).…”

Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

“…Time-lapse imaging studies of haploid wild-type cells expressing PBD-RFP and Cdc3-GFP show that Cdc42-GTP starts to accumulate around the septin ring within a few minutes after the onset of cytokinesis (i.e. t=0 when the Cdc3-GFP ring split) at 22°C and 30°C (Kang et al, 2014). Interestingly, the site with the highest Cdc42-GTP level was established quickly, near the bud neck in mother cells, and the position remained stable at the same site where the new septin ring appeared (85%, n=27; Fig.…”

Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

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Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast

Lee

Miller

et al. 2015

Journal of Cell Science

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Cdc42 plays a central role in establishing polarity in yeast and animals, yet how polarization of Cdc42 is achieved in response to spatial cues is poorly understood. Using live-cell imaging, we found distinct dynamics of Cdc42 polarization in haploid budding yeast in correlation with two temporal steps of the G1 phase. The position at which the Cdc42-GTP cluster develops changes rapidly around the division site during the first step but becomes stabilized in the second step, suggesting that an axis of polarized growth is determined in mid G1. Cdc42 polarization in the first step and its proper positioning depend on Rsr1 and its GTPase-activating protein (GAP) Bud2. Interestingly, Rga1, a Cdc42 GAP, exhibits transient localization to a site near the bud neck and to the division site during cytokinesis and G1, and this temporal change of Rga1 distribution is necessary for determination of a proper growth site. Mathematical modeling suggests that a proper axis of Cdc42 polarization in haploid cells might be established through a biphasic mechanism involving sequential positive feedback and transient negative feedback.

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Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

Section: Dynamics Of Cdc42 Polarization In Haploid Cellsmentioning

confidence: 99%

See 2 more Smart Citations

Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast

Lee

Miller

et al. 2015

Journal of Cell Science

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“…Budding yeast also has a second GEF Bud3, which establishes a proper bud site (Kang et al, 2014). During G1 in budding yeast, bud emergence occurs via biphasic Cdc42 activation by the two GEFs: Bud3 helps select the bud site (Kang et al, 2014), and Cdc24 allows polarization (Sloat et al, 1981;Sloat and Pringle, 1978).…”

Section: Significance Of Gef Coordination In Other Systemsmentioning

confidence: 99%

A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis

Hercyk

Rich

Das

2018

Preprint

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Cdc42, a conserved regulator of cell polarity, is activated by two GEFs, Gef1 and Scd1, in fission yeast. While gef1 and scd1 mutants exhibit distinct phenotypes, how they do so is unclear given that they activate the same GTPase. Using the GEF localization pattern during cytokinesis as a paradigm, we report a novel interplay between Gef1 and Scd1 that spatially modulates Cdc42. We find that Gef1 promotes Scd1 localization to the division site during cytokinesis and to the new end during polarized growth through the recruitment of the scaffold Scd2 via a Cdc42 feedforward pathway. Gef1-mediated Scd1 recruitment at the new end enables the transition from monopolar to bipolar growth. Reciprocally, Scd1 restricts Gef1 localization to prevent ectopic Cdc42 activation during cytokinesis to promote cell separation and during interphase to maintain cell shape. Our findings reveal an elegant regulatory pattern in which Gef1 establishes new sites of Scd1-mediated Cdc42 activity, while Scd1 restricts Gef1 to functional sites. We propose that crosstalk between GEFs is a conserved mechanism that orchestrates Cdc42 activation during complex cellular processes.Summary StatementCdc42 GEFs Gef1 and Scd1 crosstalk to fine-tune Cdc42 activity. This crosstalk promotes bipolar growth and maintains cell shape in fission yeast.

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Spontaneous cell polarization: Feedback control of Cdc42 GTPase breaks cellular symmetry

Martin

2015

BioEssays

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Spontaneous polarization without spatial cues, or symmetry breaking, is a fundamental problem of spatial organization in biological systems. This question has been extensively studied using yeast models, which revealed the central role of the small GTPase switch Cdc42. Active Cdc42‐GTP forms a coherent patch at the cell cortex, thought to result from amplification of a small initial stochastic inhomogeneity through positive feedback mechanisms, which induces cell polarization. Here, I review and discuss the mechanisms of Cdc42 activity self‐amplification and dynamic turnover. A robust Cdc42 patch is formed through the combined effects of Cdc42 activity promoting its own activation and active Cdc42‐GTP displaying reduced membrane detachment and lateral diffusion compared to inactive Cdc42‐GDP. I argue the role of the actin cytoskeleton in symmetry breaking is not primarily to transport Cdc42 to the active site. Finally, negative feedback and competition mechanisms serve to control the number of polarization sites.

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Bud3 activates Cdc42 to establish a proper growth site in budding yeast

Abstract: Biphasic activation of Cdc42 by Bud3 and then Cdc24 during G1 of the yeast cell cycle is necessary for assembly of a proper bud site.

Cited by 42 publications

References 57 publications

Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast

Regulation of Cdc42 polarization by the Rsr1 GTPase and Rga1, a Cdc42 GTPase-activating protein, in budding yeast

A novel interplay between GEFs orchestrates Cdc42 activity during cell polarity and cytokinesis

Spontaneous cell polarization: Feedback control of Cdc42 GTPase breaks cellular symmetry

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