Cdc42 regulates polarized growth and cell integrity in fission yeast

2014 ◽  
Vol 42 (1) ◽  
pp. 201-205 ◽  
Author(s):  
Sergio A. Rincón ◽  
Miguel Estravís ◽  
Pilar Pérez
Keyword(s):  
Cell Growth ◽  
Fission Yeast ◽  
Rho Gtpase ◽  
Short Review ◽  
Model Systems ◽  
Polarized Growth ◽  
Cell Integrity ◽  
Polarized Cell Growth ◽  
New Material ◽  
High Level

Polarized cell growth requires a well-orchestrated number of events, namely selection of growth site, organization of cytoskeleton elements and delivery of new material to the growth region. The small Rho GTPase Cdc42 has emerged as a major organizer of polarized growth through its participation in many of these events. In the present short review, we focus on the regulation of Cdc42 activity and localization as well as how it controls downstream events necessary for polarized cell growth in Schizosaccharomyces pombe. Owing to the high level of similarity of the polarity pathways, analogies between fission yeast and other model systems can be useful to decipher how cells can actively define their shape by polarized growth.

scholarly journals ThePXL1Gene ofSaccharomyces cerevisiaeEncodes a Paxillin-like Protein Functioning in Polarized Cell Growth

2004 ◽  
Vol 15 (4) ◽  
pp. 1904-1917 ◽  
Author(s):  
Nancy A. Mackin ◽  
Tarek J. Sousou ◽  
Scott E. Erdman
Keyword(s):  
Cell Growth ◽  
Rho Gtpase ◽  
Cell Types ◽  
Scaffolding Protein ◽  
Polarized Growth ◽  
Lim Domain ◽  
Reading Frame ◽  
Growth Defects ◽  
Pathway Activation ◽  
Polarized Cell Growth

The Saccharomyces cerevisiae open reading frame YKR090w encodes a predicted protein displaying similarity in organization to paxillin, a scaffolding protein that organizes signaling and actin cytoskeletal regulating activities in many higher eucaryotic cell types. We found that YKR090w functions in a manner analogous to paxillin as a mediator of polarized cell growth; thus, we have named this gene PXL1 (Paxillin-like protein 1). Analyses of pxl1Δ strains show that PXL1 is required for the selection and maintenance of polarized growth sites during vegetative growth and mating. Genetic analyses of strains lacking both PXL1 and the Rho GAP BEM2 demonstrate that such cells display pronounced growth defects in response to different conditions causing Rho1 pathway activation. PXL1 also displays genetic interactions with the Rho1 effector FKS1. Pxl1p may therefore function as a modulator of Rho-GTPase signaling. A GFP::Pxl1 fusion protein localizes to sites of polarized cell growth. Experiments mapping the localization determinants of Pxl1p demonstrate the existence of localization mechanisms conserved between paxillin and Pxl1p and indicate an evolutionarily ancient and conserved role for LIM domain proteins in acting to modulate cell signaling and cytoskeletal organization during polarized growth.

scholarly journals Regulation of the Formin for3p by cdc42p and bud6p

2007 ◽  
Vol 18 (10) ◽  
pp. 4155-4167 ◽  
Author(s):  
Sophie G. Martin ◽  
Sergio A. Rincón ◽  
Roshni Basu ◽  
Pilar Pérez ◽  
Fred Chang
Keyword(s):  
Cell Growth ◽  
Fission Yeast ◽  
Rho Gtpase ◽  
Intramolecular Interaction ◽  
Actin Cable ◽  
Polarized Cell Growth ◽  
N Terminus ◽  
Cable Assembly ◽  
Actin Cables

Formins are conserved actin nucleators responsible for the assembly of diverse actin structures. Many formins are controlled through an autoinhibitory mechanism involving the interaction of a C-terminal DAD sequence with an N-terminal DID sequence. Here, we show that the fission yeast formin for3p, which mediates actin cable assembly and polarized cell growth, is regulated by a similar autoinhibitory mechanism in vivo. Multiple sites govern for3p localization to cell tips. The localization and activity of for3p are inhibited by an intramolecular interaction of divergent DAD and DID-like sequences. A for3p DAD mutant expressed at endogenous levels produces more robust actin cables, which appear to have normal organization and dynamics. We identify cdc42p as the primary Rho GTPase involved in actin cable assembly and for3p regulation. Both cdc42p, which binds at the N terminus of for3p, and bud6p, which binds near the C-terminal DAD-like sequence, are needed for for3p localization and full activity, but a mutation in the for3p DAD restores for3p localization and other phenotypes of cdc42 and bud6 mutants. In particular, the for3p DAD mutation suppresses the bipolar growth (NETO) defect of bud6Δ cells. These findings suggest that cdc42p and bud6p activate for3p by relieving autoinhibition.

scholarly journals Activation of polarized cell growth by inhibition of cell polarity

2018 ◽  
Author(s):  
Marco Geymonat ◽  
Anatole Chessel ◽  
James Dodgson ◽  
Hannah Punter ◽  
Felix Horns ◽  
...  
Keyword(s):  
Cell Growth ◽  
Fission Yeast ◽  
Cell Polarity ◽  
Rho Gtpase ◽  
Dependent Manner ◽  
Polarized Cell Growth ◽  
And Control ◽  
Polarity Factor ◽  
Pak Kinase

AbstractA key feature of cells is the capacity to activate new functional polarized domains contemporaneously to pre-existing ones. How cells accomplish this is not clear. Here, we show that in fission yeast inhibition of cell polarity at pre-existing domains of polarized cell growth is required to activate new growth. This inhibition is mediated by the ERM-related polarity factor Tea3, which antagonizes the activation of the Rho-GTPase Cdc42 by its co-factor Scd2. We demonstrate that Tea3 acts in a phosphorylation-dependent manner controlled by the PAK kinase Shk1 and that, like Scd2, Tea3 is direct substrate of Shk1. Importantly, we show that Tea3 and Scd2 compete for their binding to Shk1, indicating that their biochemical competition for Shk1 underpins their antagonistic roles in controlling polarity. Thus, by preventing pre-existing growth domains from becoming overpowering, Tea3 allows cells to redistribute their polarity-activating machinery to prospective sites and control their timing of activation.

scholarly journals Regulation of polarized growth initiation and termination cycles by the polarisome and Cdc42 regulators

2004 ◽  
Vol 164 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Scott Bidlingmaier ◽  
Michael Snyder
Keyword(s):  
Cell Differentiation ◽  
Cell Growth ◽  
Fusion Proteins ◽  
Eukaryotic Cell ◽  
Yeast Cells ◽  
Polarized Growth ◽  
High Concentration ◽  
Dynamic Regulation ◽  
Polarized Cell Growth ◽  
Growth Initiation

The dynamic regulation of polarized cell growth allows cells to form structures of defined size and shape. We have studied the regulation of polarized growth using mating yeast as a model. Haploid yeast cells treated with high concentration of pheromone form successive mating projections that initiate and terminate growth with regular periodicity. The mechanisms that control the frequency of growth initiation and termination under these conditions are not well understood. We found that the polarisome components Spa2, Pea2, and Bni1 and the Cdc42 regulators Cdc24 and Bem3 control the timing and frequency of projection formation. Loss of polarisome components and mutation of Cdc24 decrease the frequency of projection formation, while loss of Bem3 increases the frequency of projection formation. We found that polarisome components and the cell fusion proteins Fus1 and Fus2 are important for the termination of projection growth. Our results define the first molecular regulators that control the timing of growth initiation and termination during eukaryotic cell differentiation.

scholarly journals Cytokinesis-Based Constraints on Polarized Cell Growth in Fission Yeast

PLoS Genetics ◽  
2012 ◽  
Vol 8 (10) ◽  
pp. e1003004 ◽  
Author(s):  
K. Adam Bohnert ◽  
Kathleen L. Gould
Keyword(s):  
Cell Growth ◽  
Fission Yeast ◽  
Polarized Cell Growth

scholarly journals Roles of fission yeast tea1p in the localization of polarity factors and in organizing the microtubular cytoskeleton

2002 ◽  
Vol 157 (5) ◽  
pp. 783-793 ◽  
Author(s):  
Ralf Behrens ◽  
Paul Nurse
Keyword(s):  
Cell Growth ◽  
Yeast Cell ◽  
Fission Yeast ◽  
Coiled Coil ◽  
Live Imaging ◽  
Cylindrical Shape ◽  
Polarized Growth ◽  
Coiled Coil Domain ◽  
Straight Line ◽  
Microtubular Cytoskeleton

The cylindrical shape of the fission yeast cell is generated by linear polarized growth from its cell ends. Using immunofluorescence and live imaging microscopy, we have investigated the roles of the cell end marker tea1p in generating linear polarized growth. We found that tea1p is primarily transported on plus ends of microtubules from the vicinity of the nucleus to the cell ends, and that its movement near the nucleus is independent of the kinesin tea2p. Deletion analysis identified a coiled-coil domain in tea1p essential for its retention at cell ends, and demonstrated that tea1p exerts different functions dependent on its location. On the tips of microtubules, tea1p prevents the curling of microtubules around the cell ends, whereas it is required for maintaining linear cell growth and for retention of polarity factors such as the Dyrk kinase pom1p, the CLIP170-like tip1p, and tea2p at the cell ends. We propose that tea1p has roles in organizing the microtubule cytoskeleton on the tips of microtubules, and in the retention of factors at the cell ends necessary for the cell to grow in a straight line.

COGNITIVIZATION — THE NEXT STAGE OF INFORMATIZATION OF EDUCATION

2018 ◽  
pp. 5-11
Author(s):  
A. S. Christochevskaya ◽  
S. A. Christochevsky
Keyword(s):  
Comparative Analysis ◽  
Learning Resources ◽  
Technical Base ◽  
Initial Stage ◽  
New Knowledge ◽  
Good Material ◽  
E Learning ◽  
New Material ◽  
High Level ◽  
Paper Method

Informatization of education has been going on for 30 years. During this time, a good material and technical base appeared in schools, there are repositories of e-learning resources to which teachers have access. However, it is difficult to use these e-learning resources due to their too large number and not always high level. It is advisable to introduce a system of reviews and recommendations, to conduct a comparative analysis, as well as to make reviews of resources on a particular subject/topic. In addition, the demand for e-learning resources is affected by the fact that education authorities encourage not so much the use of e-learning resources as their development by the teacher himself. In general, the load on teachers has increased instead of the promised saving of time and effort when using the e-learning resources. At the same time, many e-learning resources are not very effective, since they do not meet the requirements of cognitiveness (they contribute not to learning, but to simple memorization of the material). It is necessary to explore the process of learning new material: this will allow you to create cognitive e-learning resources and other resources that would help you with equal probability to successfully acquire new knowledge for students belonging to different psycho-types. At the initial stage of the study of any subject, it is more expedient to use the usual “paper” method, that is, a textbook and not overload the student’s brain with excessive information. Only when he has mastered the basic provisions, we can turn to e-learning resources, bearing in mind that they must be cognitive, that is, they are aimed at logical perception and rapid intuitive learning, only in this case e-learning resources can be considered effective. The conclusion is formulated that cognitiveness is the next stage of informatization of education after the stage of electronization.

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