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Curr Genet 2018 Jun 5;64(3):713-727. Epub 2017 Dec 5.

Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780, Bochum, Germany.

The filamentous fungus Acremonium chrysogenum is the primordial producer of the β-lactam antibiotic cephalosporin C. This antibiotic is of major biotechnological and medical relevance because of its antibacterial activity against Gram-positive and Gram-negative bacteria. Antibiotic production during the lag phase of fermentation is often accompanied by a typical morphological feature of A. Read More

PLoS Comput Biol 2017 Nov 9;13(11):e1005843. Epub 2017 Nov 9.

Department of Mathematics, The Ohio State University, Columbus, Ohio, United States of America.

Budding yeast, which undergoes polarized growth during budding and mating, has been a useful model system to study cell polarization. Bud sites are selected differently in haploid and diploid yeast cells: haploid cells bud in an axial manner, while diploid cells bud in a bipolar manner. While previous studies have been focused on the molecular details of the bud site selection and polarity establishment, not much is known about how different budding patterns give rise to different functions at the population level. Read More

Sci Rep 2016 05 26;6:26464. Epub 2016 May 26.

Institute of Health Sciences, Anhui University, Hefei 230601, China.

The exocyst plays a crucial role in the targeting of secretory vesicles to the plasma membrane during exocytosis. It has been shown to be involved in diverse cellular processes including yeast budding. However, the mechanism of the exocyst regulating yeast budding has not been fully elucidated. Read More

Proc Natl Acad Sci U S A 2016 Apr 21;113(14):E2019-28. Epub 2016 Mar 21.

Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260

A fundamental problem in cell biology is to understand how spatial information is recognized and integrated into morphogenetic responses. Budding yeast undergoes differentiation to filamentous growth, which involves changes in cell polarity through mechanisms that remain obscure. Here we define a regulatory input where spatial landmarks (bud-site-selection proteins) regulate the MAPK pathway that controls filamentous growth (fMAPK pathway). Read More

Mol Biol Cell 2013 Dec 9;24(23):3620-33. Epub 2013 Oct 9.

Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250 Flow Cytometry Core Facility, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.

The biogenesis of ribosomes is coordinated with cell growth and proliferation. Distortion of the coordinated synthesis of ribosomal components affects not only ribosome formation, but also cell fate. However, the connection between ribosome biogenesis and cell fate is not well understood. Read More

Philos Trans R Soc Lond B Biol Sci 2013 23;368(1629):20130006. Epub 2013 Sep 23.

Department of Pharmacology and Cancer Biology, Duke University Medical Center, , Durham, NC 27710, USA.

Saccharomyces cerevisiae yeast cells polarize in order to form a single bud in each cell cycle. Distinct patterns of bud-site selection are observed in haploid and diploid cells. Genetic approaches have identified the molecular machinery responsible for positioning the bud site: during bud formation, specific locations are marked with immobile landmark proteins. Read More

Mol Microbiol 2012 Jul 19;85(2):252-70. Epub 2012 Jun 19.

Department of Plant Pathology, University of Nebraska, Lincoln, NE 68588-0660, USA.

The yeast bud site selection system represents a paradigm for understanding how fungal cells regulate the formation of a polarity axis. In Saccharomyces cerevisiae, Bud4 and Axl2 are components of the axial bud site marker. To address the possibility that these proteins regulate cellular morphogenesis in filamentous fungi, we have characterized homologues of Bud4 and Axl2 in Aspergillus nidulans. Read More

Fungal Biol 2011 Jun 26;115(6):557-68. Epub 2011 Feb 26.

Universität Osnabrück, Institut für Genetik, Barbarastr. 11, 49076 Osnabrück, Germany.

In the filamentous ascomycete Ashbya gossypii polarity establishment at sites of germ tube and lateral branch emergence depends on homologues of Saccharomyces cerevisiae factors controlling bud site selection and bud emergence. Maintenance of polar growth involves homologues of well-known polarity factors of budding yeast. To achieve the much higher rates of sustained polar surface expansion of hyphae compared to mainly non-polarly growing yeast buds five important alterations had to evolve. Read More

Genetics 2010 May 22;185(1):165-76. Epub 2010 Feb 22.

Department of Plant Pathology and Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA.

The ability of fungi to generate polarized cells with a variety of shapes likely reflects precise temporal and spatial control over the formation of polarity axes. The bud site selection system of Saccharomyces cerevisiae represents the best-understood example of such a morphogenetic regulatory system. However, the extent to which this system is conserved in the highly polarized filamentous fungi remains unknown. Read More

J Cell Sci 2007 Oct 25;120(Pt 20):3613-24. Epub 2007 Sep 25.

Institute of Biochemistry, Christian Albrecht University Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.

The Saccharomyces cerevisiae p21-activated kinase (PAK) Ste20 regulates various aspects of cell polarity during vegetative growth, mating and filamentous growth. To gain further insight into the mechanisms of Ste20 action, we screened for interactors of Ste20 using the split-ubiquitin system. Among the identified proteins were Erg4, Cbr1 and Ncp1, which are all involved in sterol biosynthesis. Read More

J Microbiol 2007 Jun;45(3):227-33

Research and Development Center, Pigeon, Chopyeongmyeon, Jincheon, Chungbuk, Republic of Korea.

In budding yeast, septin plays as a scaffold to recruits protein components and regulates crucial cellular events including bud site selection, bud morphogenesis, Cdc28 activation pathway, and cytokinesis. Phosphorylation of Bni5 isolated as a suppressor for septin defect is essential to Swe1-dependent regulation of bud morphogenesis and mitotic entry. The mechanism by which Bni5 regulates normal septin function is not completely understood. Read More

Yeast 2005 Oct;22(14):1143-53

Department of Medical Biochemistry and Genetics, Texas A&M University System, Health Science Center, 428 Reynolds Medical Building, College Station, TX 77843-1114, USA.

Unicellular S. cerevisiae cells switch from the yeast form to pseudohyphal or filamentous form in response to environmental cues. We report that wild-type BY diploids (in which yeast ORFs have been systematically deleted) undergo normal HU-induced filamentous growth and discernable nitrogen starvation-induced filamentous growth, despite their perceived filamentation-deficient S288C genetic background. Read More

Dev Cell 2005 Oct;9(4):565-71

Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.

Cellular polarization is often a response to distinct extracellular or intracellular cues, such as nutrient gradients or cortical landmarks. However, in the absence of such cues, some cells can still select a polarization axis at random. Positive feedback loops promoting localized activation of the GTPase Cdc42p are central to this process in budding yeast. Read More

Mol Biol Cell 2003 Sep 29;14(9):3782-803. Epub 2003 May 29.

Department of Biology Queen's University, Kingston, Ontario K7L 3N6, Canada.

In Saccharomyces cerevisiae, polarized morphogenesis is critical for bud site selection, bud development, and cell separation. The latter is mediated by Ace2p transcription factor, which controls the daughter cell-specific expression of cell separation genes. Recently, a set of proteins that include Cbk1p kinase, its binding partner Mob2p, Tao3p (Pag1p), and Hym1p were shown to regulate both Ace2p activity and cellular morphogenesis. Read More

Mol Cell Biol 2003 Apr;23(8):2762-77

Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA.

The septins are a family of cytoskeletal proteins present in animal and fungal cells. They were first identified for their essential role in cytokinesis, but more recently, they have been found to play an important role in many cellular processes, including bud site selection, chitin deposition, cell compartmentalization, and exocytosis. Septin proteins self-associate into filamentous structures that, in yeast cells, form a cortical ring at the mother bud neck. Read More

J Cell Biol 2002 Nov;159(4):601-11

Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.

Cytokinesis requires the polarization of the actin cytoskeleton, the secretion machinery, and the correct positioning of the division axis. Budding yeast cells commit to their cytokinesis plane by choosing a bud site and polarizing their growth. Iqg1p (Cyk1p) was previously implicated in cytokinesis (Epp and Chant, 1997; Lippincott and Li, 1998; Osman and Cerione, 1998), as well as in the establishment of polarity and protein trafficking (Osman and Cerione, 1998). Read More

Curr Biol 2002 Aug;12(15):1347-52

Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.

Bud-site selection in yeast offers an attractive system for studying cell polarity and asymmetric division. Haploids divide in an axial pattern, whereas diploids divide in a bipolar pattern. AXL1 is expressed in haploids but not diploids, and ectopic expression of AXL1 in diploids converts their bipolar budding pattern to an axial pattern. Read More

Curr Opin Microbiol 2002 Apr;5(2):179-86

Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06520-8103, USA.

Polarized growth involves a hierarchy of events such as selection of the growth site, polarization of the cytoskeleton to the selected growth site, and transport of secretory vesicles containing components required for growth. The budding yeast Saccharomyces cerevisiae is an excellent model system for the study of polarized cell growth. A large number of proteins have been found to be involved in these processes, although their mechanisms of action are not yet well-understood. Read More

J Cell Biol 1997 Dec;139(7):1821-33

Department of Biochemistry and Molecular Biology, The Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey, Pennsylvania 17033, USA.

Yeast verprolin, encoded by VRP1, is implicated in cell growth, cytoskeletal organization, endocytosis and mitochondrial protein distribution and function. We show that verprolin is also required for bipolar bud-site selection. Previously we reported that additional actin suppresses the temperature-dependent growth defect caused by a mutation in VRP1. Read More