Saccharomyces cerevisiae Bni4p directs the formation of the chitin ring and also participates in the correct assembly of the septum structure

Sanz, M. Luz; Castrejón, Francisco; Durán, Abraham Madroñal; Roncero, César

doi:10.1099/mic.0.27352-0

Cited by 30 publications

(48 citation statements)

References 38 publications

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“…To investigate the mechanism of asymmetric protein binding to septin filaments, we have focused on the yeast protein Bni4. This protein localizes to the outside of the septin ring prior to budding and remains restricted to the mother-side of the neck as the septin ring develops into a collar during bud emergence (DeMarini et al, 1997;Kozubowski et al, 2005;Kozubowski et al, 2003;Sanz et al, 2004). This asymmetry is maintained in mutants that have defects in septin architecture, including cla4, gin4 and elm1 .…”

Section: Introductionmentioning

confidence: 98%

Changes in Bni4 localization induced by cell stress in Saccharomyces cerevisiae

Larson

Kozubowski

Tatchell

2010

Journal of Cell Science

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SummarySeptin complexes at the bud neck in Saccharomyces cerevisiae serve as a scaffold for proteins involved in signaling, cell cycle control, and cell wall synthesis. Many of these bind asymmetrically, associating with either the mother-or daughter-side of the neck. Septin structures are inherently apolar so the basis for the asymmetric binding remains unknown. Bni4, a regulatory subunit of yeast protein phosphatase type 1, Glc7, binds to the outside of the septin ring prior to bud formation and remains restricted to the mother-side of the bud neck after bud emergence. Bni4 is responsible for targeting Glc7 to the mother-side of the bud neck for proper deposition of the chitin ring. We show here that Bni4 localizes symmetrically, as two distinct rings on both sides of the bud neck following energy depletion or activation of cell cycle checkpoints. Our data indicate that loss of Bni4 asymmetry can occur via at least two different mechanisms. Furthermore, we show that Bni4 has a Swe1-dependent role in regulating the cell morphogenesis checkpoint in response to hydroxyurea, which suggests that the change in localization of Bni4 following checkpoint activation may help stabilize the cell cycle regulator Swe1 during cell cycle arrest.

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Section: Introductionmentioning

confidence: 98%

Changes in Bni4 localization induced by cell stress in Saccharomyces cerevisiae

Larson

Kozubowski

Tatchell

2010

Journal of Cell Science

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“…Chs3 and Chs4 are associated with the plasma membrane just before formation of the chitin ring at the site of bud emergence and reside there in a ring at the base of the bud in many cells with small buds, then become scarcely detectable in cells with medium-sized buds, only to reappear, in a Bni4-independent manner, at both sides of the neck in cells with large buds prior to cytokinesis DeMarini et al 1997;Santos and Snyder 1997;Kozubowski et al 2003;Sanz et al 2004). In between, Chs3 is retrieved from the membrane to chitosomes in an endocytic process dependent on End4/Sla2 Ziman et al 1996Ziman et al , 1998, but is recruited back to the plasma membrane in a Chs6-dependent manner (Ziman et al 1998;Wang et al 2006).…”

Section: Biosynthesis Of Wall Components At the Plasma Membranementioning

confidence: 99%

“…There, it interacts with the scaffold protein Bni4, which in turn associates with the septins (DeMarini et al 1997;Kozubowski et al 2003;Sanz et al 2004). Absence of Bni4 leads to mislocalized deposition of chitin (DeMarini et al 1997;Kozubowski et al 2003;Sanz et al 2004), and Chs4 is absent from the base of buds in small-budded cells (Sanz et al 2004).…”

Section: Biosynthesis Of Wall Components At the Plasma Membranementioning

confidence: 99%

“…chs3D mutants form a three-layered septum, but the neck region between mother cell and bud is elongated (Shaw et al 1991). chs2D chs3D and chs1D chs2D chs3D strains grow very slowly on osmotically supported medium (Sanz et al 2004;Schmidt 2004;File S6). The triple mutants, however, acquired a suppressor mutation that eliminated the need for osmotic support and conferred a growth rate as fast as that of a chs2D mutant although over a third of suppressed and unsuppressed cells in a culture were dead (Schmidt 2004).…”

Section: Biosynthesis Of Wall Components At the Plasma Membranementioning

confidence: 99%

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Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

2012

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The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of b1,3-and b1,6-glucans, a small amount of chitin, and many different proteins that may bear N-and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N-and O-linked glycans, glycosylphosphatidylinositol membrane anchors, b1,3-and b1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. TABLE OF CONTENTS Abstract 775Introduction 777

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“…localization at the neck and correct formation of the chitin ring (Sanz et al, 2004). However, this latter function is independent of CSIII activation since bni4⌬ cells contain normal amounts of chitin (Sanz et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Chitin synthase III requires Chs4p-dependent translocation of Chs3p into the plasma membrane

Reyes

Sanz

Durán

et al. 2007

Journal of Cell Science

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In Saccharomyces cerevisiae, Chs4p is required for chitin synthase III (CSIII) activity and hence for chitin synthesis. This protein is transported in vesicles in a polarized fashion independently of the other Chs proteins. Its association with membranes depends not only on prenylation, but also on its interaction with other proteins, mainly Chs3p, which is the catalytic subunit of CSIII and is able to properly direct Chs4p to the bud neck in the absence of prenylation. Chs4p is present in functionally limiting amounts and its overexpression increases Chs3p accumulation at the plasma membrane with a concomitant increase in chitin synthesis. In the absence of Chs4p, Chs3p is delivered to the plasma membrane but fails to accumulate there because it is rapidly endocytosed and accumulates in intracellular vesicles. A blockade of endocytosis stops Chs3p internalization, triggering a significant increase in chitin synthesis. This blockade is independent of Chs4p function, allowing the accumulation of Chs3p at the plasma membrane even in the chs4Δ mutant. However, the absence of Chs4p renders CSIII functionally inactive, independently of Chs3p accumulation at the plasma membrane. Chs4p thus promotes Chs3p translocation into the plasma membrane in a stable and active form. Proper CSIII turnover is maintained through the endocytic internalization of Chs3p.

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Saccharomyces cerevisiae Bni4p directs the formation of the chitin ring and also participates in the correct assembly of the septum structure

Cited by 30 publications

References 38 publications

Changes in Bni4 localization induced by cell stress in Saccharomyces cerevisiae

Changes in Bni4 localization induced by cell stress in Saccharomyces cerevisiae

Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

Chitin synthase III requires Chs4p-dependent translocation of Chs3p into the plasma membrane

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