Cell Wall Integrity and Filamentous Growth Mitogen-Activated Protein Kinase Pathways in Yeast Cell Wall Remodeling

The researchers from the State University of New York, Department of Biological Sciences, have published a report on the role of cell wall integrity and filamentous growth mitogen-activated protein kinase pathways in yeast cell wall remodeling. The study reveals that genetic screens identified genes required for filamentous growth in the budding yeast Saccharomyces cerevisiae, including transcription factors MCM1 and MATalpha2, and cell surface proteins Slg1p/Wsc1p, Wsc2p, Mid2p, and the mitogen-activated protein kinase Slt2p/Mpk1p. These proteins contribute to multiple aspects of filamentous growth, including cell elongation, cell-cell adherence, and agar invasion. The study also highlights the regulatory aspect of cell wall remodeling in yeast, where the ss-1,3-glucan layer of the cell wall inhibits the secretion of mucin-like proteins.

Key Takeaways:

• Genetic screens identified 10 genes, including MCM1, MATalpha2, PHD1, MSN2, SIR4, HMS2, MPT5, WSC2, MID2, and SLT2, as potential regulators of filamentous growth in Saccharomyces cerevisiae.
• The transcription factors MCM1 and MATalpha2 induced invasive growth by promoting diploid-specific bipolar budding in haploid cells.
• Components of the cell wall integrity pathway, including Slg1p/Wsc1p, Wsc2p, and Mid2p, contributed to multiple aspects of the filamentous growth response, including cell elongation, cell-cell adherence, and agar invasion.
• The filamentous growth pathway contributed to cell wall integrity in parallel with the cell wall integrity pathway and in opposition with the high osmolarity glycerol response pathway.
• Mass spectrometry approaches identified components of the filamentous cell wall, including mucin-like proteins Msb2p, Flo11p, and subtelomeric mucin Flo10p.
• Disruption of ss-1,3-glucan linkages induced mucin shedding and resulted in defects in cell-cell adhesion and invasion of cells into the agar matrix.

Statistics:

• 8 genes were identified as potential regulators of filamentous growth in Saccharomyces cerevisiae (MCM1, MATalpha2, PHD1, MSN2, SIR4, HMS2, MPT5, and WSC2).
• 11 proteins, including Slg1p/Wsc1p, Wsc2p, Mid2p, Slt2p/Mpk1p, Msb2p, Flo11p, and Flo10p, were identified as components of the filamentous growth pathway.
• 3 pathways, including the cell wall integrity pathway, the filamentous growth pathway, and the high osmolarity glycerol response pathway, were identified as playing a role in yeast cell wall remodeling.

Sources:

• Birkaya, B., et al. (2009). Role of the cell wall integrity and filamentous growth mitogen-activated protein kinase pathways in cell wall remodeling during filamentous growth. Eukaryotic Cell, 8(8), 1118-1133.
• Enzyme Research.