Involved in spore wall assembly. In respiratory-deficient cells and by heat. Displays increased levels of spontaneous RAD52 foci in proliferating diploid cells (PubMed:18085829). A combined deletion of the LOH1/OSW4 and IRC18/OSW6 has reduced dityrosine incorporation in the outer spore wall (PubMed:23966878). Belongs to the OSW4/6 family.