Middle sporulation-specific mitogen-activated protein kinase (MAPK); required for prospore membrane development and the production of outer spore wall layers; promotes deposition of the glucan layer of the spore wall by regulating the localization of Gsc2p to sites of spore wall assembly in postmeiotic cells; activated by Cak1p-mediated phosphorylation of threonine (T207) in the activation loop during meiosis I followed by Ssp2p-promoted autophosphorylation of tyrosine (T209) during meiosis II