title: Role of the alpha-glucanase Agn1p in fission-yeast cell separation.
abstract: Cell division in the fission yeast Schizosaccharomyces pombe yields two equal-sized daughter cells. Medial fission is achieved by deposition of a primary septum flanked by two secondary septa within the dividing cell. During the final step of cell division, cell separation, the primary septum is hydrolyzed by an endo-(1,3)-beta-glucanase, Eng1p. We reasoned that the cell wall material surrounding the septum, referred to here as the septum edging, also must be hydrolyzed before full separation of the daughter cells can occur. Because the septum edging contains (1,3)-alpha-glucan, we investigated the cellular functions of the putative (1,3)-alpha-glucanases Agn1p and Agn2p. Whereas agn2 deletion results in a defect in endolysis of the ascus wall, deletion of agn1 leads to clumped cells that remained attached to each other by septum-edging material. Purified Agn1p hydrolyzes (1,3)-alpha-glucan predominantly into pentasaccharides, indicating an endo-catalytic mode of hydrolysis. Furthermore, we show that the transcription factors Sep1p and Ace2p regulate both eng1 and agn1 expression in a cell cycle-dependent manner. We propose that Agn1p acts in concert with Eng1p to achieve efficient cell separation, thereby exposing the secondary septa as the new ends of the daughter cells.
authors.affiliation: Department of Medical Biochemistry, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands.
authors.forename: Nick
authors.initials: N
authors.lastname: Dekker
authors.forename: Dave
authors.initials: D
authors.lastname: Speijer
authors.forename: Christian H
authors.initials: CH
authors.lastname: Grün
authors.forename: Marlene
authors.initials: M
authors.lastname: van den Berg
authors.forename: Annett
authors.initials: A
authors.lastname: de Haan
authors.forename: Frans
authors.initials: F
authors.lastname: Hochstenbach
mesh_terms: D000595:Amino Acid Sequence; D002455:Cell Division / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D006026:Glycoside Hydrolases / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D012568:Schizosaccharomyces / Q000166:cytology / Q000201:enzymology* / Q000502:physiology; D029702:Schizosaccharomyces pombe Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics
chemical_list: D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; D006026:Glycoside Hydrolases; C028760:endo-1,3-alpha-glucanase