Fission yeast Ags1 confers the essential septum strength needed for safe gradual cell abscission.
Fungal cytokinesis requires the assembly of a dividing septum wall. In yeast, the septum has to be selectively digested during the critical cell separation process. Fission yeast cell wall α(1-3)glucan is essential, but nothing is known about its localization and function in the cell wall or about cooperation between the α- and β(1-3)glucan synthases Ags1 and Bgs for cell wall and septum assembly. Here, we generate a physiological Ags1-GFP variant and demonstrate a tight colocalization with Bgs1, suggesting a cooperation in the important early steps of septum construction. Moreover, we define the essential functions of α(1-3)glucan in septation and cell separation. We show that α(1-3)glucan is essential for both secondary septum formation and the primary septum structural strength needed to support the physical forces of the cell turgor pressure during cell separation. Consequently, the absence of Ags1 and therefore α(1-3)glucan generates a special and unique side-explosive cell separation due to an instantaneous primary septum tearing caused by the turgor pressure.
Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, 37007 Salamanca, Spain.
Juan Carlos G
JC
Cortés
Mamiko
M
Sato
Javier
J
Muñoz
M Belén
MB
Moreno
Jose Angel
JA
Clemente-Ramos
Mariona
M
Ramos
Hitoshi
H
Okada
Masako
M
Osumi
Angel
A
Durán
Juan Carlos
JC
Ribas
D002473:Cell Wall / Q000502:physiology* / Q000648:ultrastructure; D048749:Cytokinesis / Q000502:physiology*; D005936:Glucans / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism / Q000502:physiology*; D011312:Pressure; D012568:Schizosaccharomyces / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000502:physiology*; D013314:Stress, Mechanical
D005936:Glucans; D029702:Schizosaccharomyces pombe Proteins; C045788:alpha-1,3-glucan; D005964:Glucosyltransferases; C114021:ags1 protein, S pombe; C020570:1,3-beta-glucan synthase