The Rho GTPase Rho3 Has a Direct Role in Exocytosis That Is Distinct from Its Role in Actin Polarity

Adamo, Joan E.; Rossi, Guendalina; Brennwald, Patrick

doi:10.1091/mbc.10.12.4121

Cited by 195 publications

(238 citation statements)

References 47 publications

(52 reference statements)

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“…Interestingly, Bni1p, but not Bnr1p, also depends on the rho-GTPase Rho3p for activation (Dong et al, 2003). The requirement of Rho3p for efficient fusion of secretory vesicles with the plasma membrane (Adamo et al, 1999) may contribute to an explanation for this dependence.…”

Section: Discussionmentioning

confidence: 96%

Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Pruyne

Gao

et al. 2004

MBoC

150

208

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Bud growth in yeast is guided by myosin-driven delivery of secretory vesicles from the mother cell to the bud. We find transport occurs along two sets of actin cables assembled by two formin isoforms. The Bnr1p formin assembles cables that radiate from the bud neck into the mother, providing a stable mother-bud axis. These cables also depend on septins at the neck and are required for efficient transport from the mother to the bud. The Bni1p formin assembles cables that line the bud cortex and target vesicles to varying locations in the bud. Loss of these cables results in morphological defects as vesicles accumulate at the neck. Assembly of these cables depends on continued polarized secretion, suggesting vesicular transport provides a positive feedback signal for Bni1p activation, possibly by rho-proteins. By coupling different formin isoforms to unique cortical landmarks, yeast uses common cytoskeletal elements to maintain stable and dynamic axes in the same cell. INTRODUCTIONProper cell polarization requires a balance between dynamism and stability. Persistent systems, such as the apical and basolateral domains of epithelial cells, show a higher stability than flexible systems, such as cells undergoing chemotaxis. However, both types can use similar cytoskeletal components, so an important task in understanding the control of polarity is to identify features that influence persistence, and how those features integrate with the core cytoskeletal machinery providing the physical expression of polarity.The process of bud growth of the yeast Saccharomyces cerevisiae provides a model for examining the control of polarity (for reviews, see Bretscher, 2003;Chang and Peter, 2003). Secretory organelles, such as the Golgi and endoplasmic reticulum, are distributed throughout the bud and mother cell, whereas post-Golgi secretory vesicles concentrate at discrete growth sites at the cell cortex. These vesicles are guided to these sites along what are essentially two axes of polarity: a stable axis directing traffic from the mother into the bud, and a dynamic axis that fine-tunes delivery from the bud neck to specific regions in the bud, sending vesicles first to the small bud tip, then to the entire bud surface, and finally back toward the neck during mother/daughter separation. On delivery to these locations, post-Golgi vesicles fuse with the cell surface to promote localized cell expansion.Two class-V myosins, with heavy chains encoded by MYO2 (Johnston et al., 1991) and MYO4 (Haarer et al., 1994), propel cellular components, including vesicles, organelles, mRNAs, and microtubules, from the mother into the bud during growth and organelle segregation. The myosins move along cables of actin filaments that radiate throughout the cell in arrays oriented toward growth sites (Adams and Pringle, 1984;Kilmartin and Adams, 1984).Assembly of these cables depends on two formin homologues, Bni1p and Bnr1p (Evangelista et al., 2002;Sagot et al., 2002a), members of a family of cytoskeletal regulatory proteins defined by conserved fo...

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Section: Discussionmentioning

confidence: 96%

Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Pruyne

Gao

et al. 2004

MBoC

150

208

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“…Osteoclasts have a distinct cell polarity that causes them to move in the direction of the bone surface upon differentiation (Laitala-Leinonen et al, 1996;Adamo et al, 1999;Lopez de Heredia and Jansen, 2004). To examine whether the precursor cells appearing in periodontal tissues on the distal side of rat second molars at 3 weeks of age are moving to the molar root or alveolar bone, we investigated the intracellular localization of mRNA signals in double-FISH.…”

Section: Localization Of Mrna In Cathepsin K-positive Cells In Periodmentioning

confidence: 99%

Comparison of expression patterns of cathepsin K and MMP-9 in odontoclasts and osteoclasts in physiological root resorption in the rat molar

Tsuchiya

Akiba

Takahashi

et al. 2008

Arch. Histol. Cytol.

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Summary. Root resorption lacunae are principally formed by odontoclasts. While these cells develop from the same origin as osteoclasts, odontoclasts normally have fewer nuclei and a less clear zone compared with osteoclasts. We therefore, hypothesized that odontoclasts possess less differentiation in matrix resorption characteristics than osteoclasts. To test our hypothesis, we compared the TRAP-positive area and the expression patterns of two important proteolytic enzymes, cathepsin K and matrix metalloproteinase-9 (MMP-9), between odontoclasts and osteoclasts. We focused on physiological root resorption in the rat molar, which is a useful experimental model for estimating odontoclasts and osteoclasts. Observations showed the number of nuclei and the TRAP-positive area of odontoclasts to be significantly less compared with osteoclasts. Using in situ hybridization and double labeling fluorescence in situ hybridization showed the majority of odontoclasts to express both cathepsin K and MMP-9, especially 4 and 5 weeks of age, when physiological root resorption occurs actively. Moreover, putative precursor cells of odontoclasts, which typically appeared in the middle of the periodontal ligament at 3 weeks of age, expressed both enzymes. In contrast, the majority of matured osteoclasts expressed only cathepsin K but not MMP-9. We suggest that odontoclasts are comparable to osteoclasts with less differentiation with regard to the expression of proteolytic enzymes.

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“…25 A temperature-sensitive mutant of Rho3 (rho3-V51) shared many phenotypes with cdc42-6. 26 Moreover, overexpression of wild-type versions of each protein was capable of suppressing mutant phenotypes of the other. 25 Indeed, several late-acting secretory proteins of the exocyst family (most notably Sec9) also suppressed phenotypes of both cdc42-6 and rho3-V51, confirming that the exocyst functions downstream of Cdc42 and Rho3 to efficiently polarize secretory traffic in budding yeast.…”

Section: The Exocyst Complex and Their Regulation By Small Gtpasesmentioning

confidence: 99%

RhoGTPase-binding proteins, the exocyst complex and polarized vesicle trafficking

2014

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The Rho GTPase Rho3 Has a Direct Role in Exocytosis That Is Distinct from Its Role in Actin Polarity

Cited by 195 publications

References 47 publications

Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Stable and Dynamic Axes of Polarity Use Distinct Formin Isoforms in Budding Yeast

Comparison of expression patterns of cathepsin K and MMP-9 in odontoclasts and osteoclasts in physiological root resorption in the rat molar

RhoGTPase-binding proteins, the exocyst complex and polarized vesicle trafficking

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