Crosslinks in the cell wall of budding yeast control morphogenesis at the mother-bud neck.
Previous work has shown that, in cla4Δ cells of budding yeast, where septin ring organization is compromised, the chitin ring at the mother-daughter neck becomes essential for prevention of neck widening and for cytokinesis. Here, we show that it is not the chitin ring per se, but its linkage to β(1-3)glucan that is required for control of neck growth. When in a cla4Δ background, crh1Δ crh2Δ mutants, in which the chitin ring is not connected to β(1-3)glucan, grew very slowly and showed wide and growing necks, elongated buds and swollen cells with large vacuoles. A similar behavior was elicited by inhibition of the Crh proteins. This aberrant morphology matched that of cla4Δ chs3Δ cells, which have no chitin at the neck. Thus, this is a clear case in which a specific chemical bond between two substances, chitin and glucan, is essential for the control of morphogenesis. This defines a new paradigm, in which chemistry regulates growth.
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid,  Spain.
Noelia
N
Blanco
Michael
M
Reidy
Javier
J
Arroyo
Enrico
E
Cabib
D002473:Cell Wall / Q000378:metabolism* / Q000648:ultrastructure; D002686:Chitin / Q000378:metabolism; D005936:Glucans / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D004718:Saccharomycetales / Q000378:metabolism* / Q000648:ultrastructure
D005936:Glucans; D029701:Saccharomyces cerevisiae Proteins; D002686:Chitin; C407735:CRH1 protein, S cerevisiae; D006026:Glycoside Hydrolases; C407734:UTR2 protein, S cerevisiae