scholarly journals 2PS016 Movement of cortical actin cables is driven by type V myosins in fission yeast cells during interphase(The 50th Annual Meeting of the Biophysical Society of Japan)

2012 ◽  
Vol 52 (supplement) ◽  
pp. S112
Author(s):  
Jun Kashiwazaki ◽  
Issei Mabuchi
Keyword(s):  
Fission Yeast ◽  
Annual Meeting ◽  
Yeast Cells ◽  
Cortical Actin ◽  
Biophysical Society ◽  
Actin Cables ◽  
Type V

scholarly journals Sequestration of the exocytic SNARE Psy1 into multiprotein nodes reinforces polarized morphogenesis in fission yeast

2021 ◽  
pp. mbc.E20-05-0277
Author(s):  
Kristi E. Miller ◽  
Joseph O. Magliozzi ◽  
Noelle A. Picard ◽  
James B. Moseley
Keyword(s):  
Fission Yeast ◽  
Cell Morphology ◽  
Growth Pattern ◽  
Yeast Cells ◽  
Cell Cortex ◽  
Interacting Proteins ◽  
Cell Width ◽  
Growing Cell ◽  
Actin Cables ◽  
Genetic Results

Polarized morphogenesis is achieved by targeting or inhibiting growth at distinct regions. Rod-shaped fission yeast cells grow exclusively at their ends by restricting exocytosis and secretion to these sites. This growth pattern implies the existence of mechanisms that prevent exocytosis and growth along non-growing cell sides. We previously identified a set of 50-100 megadalton-sized node structures along the sides of fission yeast cells that contain the interacting proteins Skb1 and Slf1. Here, we show that Skb1-Slf1 nodes contain the syntaxin-like SNARE Psy1, which mediates exocytosis in fission yeast. Psy1 localizes in a diffuse pattern at cell tips where it likely promotes exocytosis and growth, but Psy1 is sequestered in Skb1-Slf1 nodes at cell sides where growth does not occur. Mutations that prevent node assembly or inhibit Psy1 localization to nodes lead to aberrant exocytosis at cell sides and increased cell width. Genetic results indicate that this Psy1 node mechanism acts in parallel to actin cables and Cdc42 regulation. Our work suggests that sequestration of syntaxin-like Psy1 at non-growing regions of the cell cortex reinforces cell morphology by restricting exocytosis to proper sites of polarized growth.

Isolation and characterization of fission yeast mutants defective in the assembly and placement of the contractile actin ring

1996 ◽  
Vol 109 (1) ◽  
pp. 131-142 ◽  
Author(s):  
F. Chang ◽  
A. Woollard ◽  
P. Nurse
Keyword(s):  
Fission Yeast ◽  
Ring Formation ◽  
Cell Cycle Checkpoint ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Actin Ring ◽  
Division Site ◽  
Isolation And Characterization ◽  
Cycle Checkpoint ◽  
Actin Cables

Fission yeast cells divide by medial cleavage using an actin-based contractile ring. We have conducted a genetic screen for temperature-sensitive mutants defective in the assembly and placement of this actin ring. Six genes necessary for actin ring formation and one gene necessary for placement of the actin ring have now been identified. The genes can be further organized into different phenotypic groups, suggesting that the gene products may have different functions in actin ring formation. Mutants of cdc3 and cdc8, which encode profilin and tropomyosin respectively, display disorganized actin patches in all cells. cdc12 and cdc15 mutants display disorganized actin patches during mitosis, but normal interphase actin patterns. cdc4 and rng2 mutants display disorganized actin cables during mitosis, but normal interphase actin patterns. In mid1 mutants, the actin ring and septum are positioned at random locations and angles on the cell surface, although the nucleus is positioned normally, indicating that the mid1 gene product is required to couple the division site to the position of the nucleus. mid1 mutant cells may reveal a new cell cycle checkpoint in telophase that coordinates cell division and the proper distribution of nuclei. The actin ring forms medially in a beta-tubulin mutant, showing that actin ring formation and placement are not dependent on the mitotic spindle.

1P322 Quantitative analyses of chromatin dynamics in fission yeast(30. Miscellaneous topics,Poster,The 52nd Annual Meeting of the Biophysical Society of Japan(BSJ2014))

2014 ◽  
Vol 54 (supplement1-2) ◽  
pp. S194
Author(s):  
Takeshi Sugawara ◽  
Shota Masuda ◽  
Jun-ichi Uewaki ◽  
Akinori Awazu ◽  
Hiraku Nishimori ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Annual Meeting ◽  
Chromatin Dynamics ◽  
Biophysical Society ◽  
Quantitative Analyses

scholarly journals Actin cables and the exocyst form two independent morphogenesis pathways in the fission yeast

2011 ◽  
Vol 22 (1) ◽  
pp. 44-53 ◽  
Author(s):  
Felipe O. Bendezú ◽  
Sophie G. Martin
Keyword(s):  
Plasma Membrane ◽  
Fission Yeast ◽  
Long Range ◽  
Cell Types ◽  
Yeast Cells ◽  
Long Range Transport ◽  
Dependent Manner ◽  
Cell Morphogenesis ◽  
Range Transport ◽  
Actin Cables

Cell morphogenesis depends on polarized exocytosis. One widely held model posits that long-range transport and exocyst-dependent tethering of exocytic vesicles at the plasma membrane sequentially drive this process. Here, we describe that disruption of either actin-based long-range transport and microtubules or the exocyst did not abolish polarized growth in rod-shaped fission yeast cells. However, disruption of both actin cables and exocyst led to isotropic growth. Exocytic vesicles localized to cell tips in single mutants but were dispersed in double mutants. In contrast, a marker for active Cdc42, a major polarity landmark, localized to discreet cortical sites even in double mutants. Localization and photobleaching studies show that the exocyst subunits Sec6 and Sec8 localize to cell tips largely independently of the actin cytoskeleton, but in a cdc42 and phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2)–dependent manner. Thus in fission yeast long-range cytoskeletal transport and PIP2-dependent exocyst represent parallel morphogenetic modules downstream of Cdc42, raising the possibility of similar mechanisms in other cell types.

scholarly journals A Type V Myosin (Myo2p) and a Rab-like G-Protein (Ypt11p) Are Required for Retention of Newly Inherited Mitochondria in Yeast Cells during Cell Division

2004 ◽  
Vol 15 (9) ◽  
pp. 3994-4002 ◽  
Author(s):  
Istvan R. Boldogh ◽  
Sharmilee L. Ramcharan ◽  
Hyeong-Cheol Yang ◽  
Liza A. Pon
Keyword(s):  
Yeast Cells ◽  
Mitochondrial Morphology ◽  
Temperature Sensitive ◽  
Myosin V ◽  
Binding Partner ◽  
Mitochondrial Movement ◽  
Mitochondrial Motility ◽  
Mother Cells ◽  
Actin Cables ◽  
Type V

Two actin-dependent force generators contribute to mitochondrial inheritance: Arp2/3 complex and the myosin V Myo2p (together with its Rab-like binding partner Ypt11p). We found that deletion of YPT11, reduction of the length of the Myo2p lever arm (myo2-Δ6IQ), or deletion of MYO4 (the other yeast myosin V), had no effect on mitochondrial morphology, colocalization of mitochondria with actin cables, or the velocity of bud-directed mitochondrial movement. In contrast, retention of mitochondria in the bud was compromised in YPT11 and MYO2 mutants. Retention of mitochondria in the bud tip of wild-type cells results in a 60% decrease in mitochondrial movement in buds compared with mother cells. In ypt11Δ mutants, however, the level of mitochondrial motility in buds was similar to that observed in mother cells. Moreover, the myo2-66 mutant, which carries a temperature-sensitive mutation in the Myo2p motor domain, exhibited a 55% decrease in accumulation of mitochondria in the bud tip, and an increase in accumulation of mitochondria at the retention site in the mother cell after shift to restrictive temperatures. Finally, destabilization of actin cables and the resulting delocalization of Myo2p from the bud tip had no significant effect on the accumulation of mitochondria in the bud tip.

scholarly journals A formin-nucleated actin aster concentrates cell wall hydrolases for cell fusion in fission yeast

2015 ◽  
Vol 208 (7) ◽  
pp. 897-911 ◽  
Author(s):  
Omaya Dudin ◽  
Felipe O. Bendezú ◽  
Raphael Groux ◽  
Thierry Laroche ◽  
Arne Seitz ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fission Yeast ◽  
Cell Fusion ◽  
Actin Filaments ◽  
Yeast Cells ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
M Cell ◽  
Cell Wall Hydrolases ◽  
Type V

Cell–cell fusion is essential for fertilization. For fusion of walled cells, the cell wall must be degraded at a precise location but maintained in surrounding regions to protect against lysis. In fission yeast cells, the formin Fus1, which nucleates linear actin filaments, is essential for this process. In this paper, we show that this formin organizes a specific actin structure—the actin fusion focus. Structured illumination microscopy and live-cell imaging of Fus1, actin, and type V myosins revealed an aster of actin filaments whose barbed ends are focalized near the plasma membrane. Focalization requires Fus1 and type V myosins and happens asynchronously always in the M cell first. Type V myosins are essential for fusion and concentrate cell wall hydrolases, but not cell wall synthases, at the fusion focus. Thus, the fusion focus focalizes cell wall dissolution within a broader cell wall synthesis zone to shift from cell growth to cell fusion.

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