CWH41 ENCODES A NOVEL ENDOPLASMIC-RETICULUM MEMBRANE N-GLYCOPROTEIN INVOLVED IN BETA-1,6-GLUCAN ASSEMBLY

CWH41 encodes a novel type II integral membrane N-glycoprotein located in the endoplasmic reticulum. Disruption of the CWH41 gene leads to a K1 killer toxin-resistant phenotype and a 50% reduction in the cell w all beta 1,6-glucan level. CWH41 also displays strong genetic interact ions with KRE1 and KRE6, two genes known to be Involved in the beta 1, 6-glucan biosynthetic pathway. The cwh41 Delta kre6 Delta double mutan t is nonviable; and the cwh41 Delta kre1 Delta double mutation results in strong synergistic defects, with a severely slow-growth phenotype, a 75% reduction in beta 1,6-glucan level, and the secretion of a cell wall glucomannoprotein, Cwp1p. These results provide strong genetic e vidence indicating that Cwh41p plays a functional role, possibly as a new synthetic component, In the assembly of cell wall beta 1,6-glucan.