In fungi the outermost cape of the spore wall is made up of a polymer that contains cross-linked amino acid dityrosine, which is important for the stress resistance of the spore [1]. The OSW family of proteins have been implicated in assembly of this protective dityrosine coat. OSW5 null mutant spores show an enhanced spore wall permeability and vulnerability to beta glucanase digestion [2]. The proteins are predicted to be integral membrane proteins [3].

1: A screen for spore wall permeability mutants identifies a secreted protease required for proper spore wall assembly. Suda Y, Rodriguez RK, Coluccio AE, Neiman AM; PLoS One. 2009;4:e7184. PMID:19779569

2: Morphogenetic pathway of spore wall assembly in Saccharomyces cerevisiae. Coluccio A, Bogengruber E, Conrad MN, Dresser ME, Briza P, Neiman AM; Eukaryot Cell. 2004;3:1464-1475. PMID:15590821

3: Topology models for 37 Saccharomyces cerevisiae membrane proteins based on C-terminal reporter fusions and predictions. Kim H, Melen K, von Heijne G; J Biol Chem. 2003;278:10208-10213. PMID:12524434