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 Gradients of phosphatidylserine contribute to plasma membrane charge localization and cell polarity in fission yeast

2017 ◽  
Vol 28 (1) ◽  
pp. 210-220 ◽  
Author(s):  
Armin Haupt ◽  
Nicolas Minc
Keyword(s):  
Plasma Membrane ◽  
Fission Yeast ◽  
Rho Gtpases ◽  
Cell Types ◽  
Dependent Manner ◽  
Surface Charges ◽  
Charge Localization ◽  
Membrane Charge ◽  
Altered Cell ◽  
And Function

Surface charges at the inner leaflet of the plasma membrane may contribute to regulate the surface recruitment of key signaling factors. Phosphatidylserine (PS) is an abundant charged lipid that may regulate charge distribution in different cell types. Here we characterize the subcellular distribution and function of PS in the rod-shaped, polarized fission yeast. We find that PS preferably accumulates at cell tips and defines a gradient of negative charges along the cell surface. This polarization depends on actin-mediated endocytosis and contributes to the subcellular partitioning of charged polarity-regulating Rho GTPases like Rho1 or Cdc42 in a protein charge–dependent manner. Cells depleted of PS have altered cell dimensions and fail to properly regulate growth from the second end, suggesting a role for PS and membrane charge in polarized cell growth.

Elemental carbon deposition to Svalbard snow from Norwegian settlements and long-range transport

Tellus B ◽  
2011 ◽  
Vol 63 (3) ◽  
Author(s):  
Borgar Aamaas ◽  
Carl Egede Bøggild ◽  
Frode Stordal ◽  
Terje Berntsen ◽  
Kim Holmén ◽  
...  
Keyword(s):  
Long Range ◽  
Elemental Carbon ◽  
Carbon Deposition ◽  
Long Range Transport ◽  
Range Transport

Long range transport ofCastanea sativapollen

Grana ◽  
1988 ◽  
Vol 27 (3) ◽  
pp. 203-207 ◽  
Author(s):  
Annie Gérard Peeters ◽  
Heinrich Zoller
Keyword(s):  
Long Range ◽  
Long Range Transport ◽  
Range Transport

scholarly journals Septin-dependent compartmentalization of the endoplasmic reticulum during yeast polarized growth

2005 ◽  
Vol 169 (6) ◽  
pp. 897-908 ◽  
Author(s):  
Cosima Luedeke ◽  
Stéphanie Buvelot Frei ◽  
Ivo Sbalzarini ◽  
Heinz Schwarz ◽  
Anne Spang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Diffusion Barriers ◽  
Yeast Cells ◽  
Dependent Manner ◽  
Protein Diffusion ◽  
Ultrastructural Studies ◽  
Bud Neck ◽  
Er Membrane

Polarized cells frequently use diffusion barriers to separate plasma membrane domains. It is unknown whether diffusion barriers also compartmentalize intracellular organelles. We used photobleaching techniques to characterize protein diffusion in the yeast endoplasmic reticulum (ER). Although a soluble protein diffused rapidly throughout the ER lumen, diffusion of ER membrane proteins was restricted at the bud neck. Ultrastructural studies and fluorescence microscopy revealed the presence of a ring of smooth ER at the bud neck. This ER domain and the restriction of diffusion for ER membrane proteins through the bud neck depended on septin function. The membrane-associated protein Bud6 localized to the bud neck in a septin-dependent manner and was required to restrict the diffusion of ER membrane proteins. Our results indicate that Bud6 acts downstream of septins to assemble a fence in the ER membrane at the bud neck. Thus, in polarized yeast cells, diffusion barriers compartmentalize the ER and the plasma membrane along parallel lines.

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