Plant PAN/APPLE-like domain; present in plant S-receptor protein kinases and secreted glycoproteins. PAN/APPLE domains fulfill diverse biological functions by mediating protein-protein or protein-carbohydrate interactions. S-receptor protein kinases and S-locus glycoproteins are involved in sporophytic self-incompatibility response in Brassica, one of probably many molecular mechanisms, by which hermaphrodite flowering plants avoid self-fertilization.