YFR016c/Aip5 is part of an actin nucleation complex in yeast

Glomb, Oliver; Bareis, Lara; Johnsson, Nils

doi:10.1242/bio.044024

Cited by 10 publications

(24 citation statements)

References 43 publications

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“…Epo1 binds Pea2 and links the cortical ER to the cell tip ( Chao et al, 2014 ; Neller et al, 2015 ). Aip5 binds Spa2 and supports the Bni1–Bud6 complex during actin polymerization ( Glomb et al, 2019 ; Xie et al, 2019 ).…”

Section: Introductionmentioning

confidence: 99%

Type V myosin focuses the polarisome and shapes the tip of yeast cells

Dünkler

Leda

Kromer

et al. 2021

Journal of Cell Biology

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The polarisome is a cortical proteinaceous microcompartment that organizes the growth of actin filaments and the fusion of secretory vesicles in yeasts and filamentous fungi. Polarisomes are compact, spotlike structures at the growing tips of their respective cells. The molecular forces that control the form and size of this microcompartment are not known. Here we identify a complex between the polarisome subunit Pea2 and the type V Myosin Myo2 that anchors Myo2 at the cortex of yeast cells. We discovered a point mutation in the cargo-binding domain of Myo2 that impairs the interaction with Pea2 and consequently the formation and focused localization of the polarisome. Cells carrying this mutation grow round instead of elongated buds. Further experiments and biophysical modeling suggest that the interactions between polarisome-bound Myo2 motors and dynamic actin filaments spatially focus the polarisome and sustain its compact shape.

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Section: Introductionmentioning

confidence: 99%

Type V myosin focuses the polarisome and shapes the tip of yeast cells

Dünkler

Leda

Kromer

et al. 2021

Journal of Cell Biology

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“…The polarisome is a macromolecular complex that is comprises the core members Spa2, Bni1, Bud6, Aip5, and Pea2 (Fujiwara et al, 1998;Glomb et al, 2019;Sheu et al, 1998;Shih et al, 2005;Tcheperegine et al, 2005;Xie et al, 2019). Rab GTPase-activating proteins (GAPs) Msb3 and Msb4 have also been suggested to be polarisome members, given their direct interactions with Spa2 (Li et al, 2013), although the role of Msb3 and Msb4 in polarisome assembly is still not known.…”

Section: Introductionmentioning

confidence: 99%

“…The polarisome complex is involved in multiple cellular activities, but the molecular mechanisms by which the dynamic ensemble of the aforementioned components is achieved, in order to support its different functions, remain unclear. Intriguingly, the polarisome complex is assembled as a dense structure and compartmentalized at the bud tip during budding yeast polarity establishment, without having a physical barrier between the polarisome and cytosol, and the packing and localization of the different polarisome complex components are dynamically tuned along with the cell cycle (Arkowitz and Lowe, 1997;Chao et al, 2014;Glomb et al, 2019;Ozaki-Kuroda et al, 2001;Segal et al, 2000;Tcheperegine et al, 2005;Xie et al, 2019). Currently, our knowledge about how the molecular assembly and disassembly of polarisome complex are regulated by the physicochemical properties of surrounding environment, such as actin treadmilling, molecular crowding or cytoplasmic rheology, is still limited.…”

Section: Introductionmentioning

confidence: 99%

Polarisome assembly mediates actin remodeling during polarized yeast and fungal growth

Xie

Miao

2021

Journal of Cell Science

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Dynamic assembly and remodeling of actin is critical for many cellular processes during development and stress adaptation. In filamentous fungi and budding yeast, actin cables align in a polarized manner along the mother-to-daughter cell axis, and are essential for the establishment and maintenance of polarity; moreover, they rapidly remodel in response to environmental cues to achieve an optimal system response. A formin at the tip region within a macromolecular complex, called the polarisome, is responsible for driving actin cable polymerization during polarity establishment. This polarisome undergoes dynamic assembly through spatial and temporally regulated interactions between its components. Understanding this process is important to comprehend the tuneable activities of the formin-centered nucleation core, which are regulated through divergent molecular interactions and assembly modes within the polarisome. In this Review, we focus on how intrinsically disordered regions (IDRs) orchestrate the condensation of the polarisome components and the dynamic assembly of the complex. In addition, we address how these components are dynamically distributed in and out of the assembly zone, thereby regulating polarized growth. We also discuss the potential mechanical feedback mechanisms by which the force-induced actin polymerization at the tip of the budding yeast regulates the assembly and function of the polarisome.

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“…Factors that promote yeast formin-mediated actin assembly include profilin, Bud6, Bil1, and Aip5 ( Evangelista et al, 1997 ; Moseley et al, 2004 ; Graziano et al, 2013 ; Glomb et al, 2019 ; Xie et al, 2019 ). Bud6 directly interacts with G-actin and the C-terminal tail regions of Bni1 and Bnr1, positioning actin monomers near their actin-nucleating formin homology 2 (FH2) domains ( Graziano et al, 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Bil2 Is a Novel Inhibitor of the Yeast Formin Bnr1 Required for Proper Actin Cable Organization and Polarized Secretion

Rands

Goode

2021

Front. Cell Dev. Biol.

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Cell growth in budding yeast depends on rapid and on-going assembly and turnover of polarized actin cables, which direct intracellular transport of post-Golgi vesicles to the bud tip. Saccharomyces cerevisiae actin cables are polymerized by two formins, Bni1 and Bnr1. Bni1 assembles cables in the bud, while Bnr1 is anchored to the bud neck and assembles cables that specifically extend filling the mother cell. Here, we report a formin regulatory role for YGL015c, a previously uncharacterized open reading frame, which we have named Bud6 Interacting Ligand 2 (BIL2). bil2Δ cells display defects in actin cable architecture and partially-impaired secretory vesicle transport. Bil2 inhibits Bnr1-mediated actin filament nucleation in vitro, yet has no effect on the rate of Bnr1-mediated filament elongation. This activity profile for Bil2 resembles that of another yeast formin regulator, the F-BAR protein Hof1, and we find that bil2Δ with hof1Δ are synthetic lethal. Unlike Hof1, which localizes exclusively to the bud neck, GFP-Bil2 localizes to the cytosol, secretory vesicles, and sites of polarized cell growth. Further, we provide evidence that Hof1 and Bil2 inhibitory effects on Bnr1 are overcome by distinct mechanisms. Together, our results suggest that Bil2 and Hof1 perform distinct yet genetically complementary roles in inhibiting the actin nucleation activity of Bnr1 to control actin cable assembly and polarized secretion.

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YFR016c/Aip5 is part of an actin nucleation complex in yeast

Cited by 10 publications

References 43 publications

Type V myosin focuses the polarisome and shapes the tip of yeast cells

Type V myosin focuses the polarisome and shapes the tip of yeast cells

Polarisome assembly mediates actin remodeling during polarized yeast and fungal growth

Bil2 Is a Novel Inhibitor of the Yeast Formin Bnr1 Required for Proper Actin Cable Organization and Polarized Secretion

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