ATP13 is necessary for the expression of subunit 9 of mitochondrial ATPase. The protein has a basic amino terminal signal sequence that is cleaved upon import into mitochondria [1].

1: ATP13, a nuclear gene of Saccharomyces cerevisiae essential for the expression of subunit 9 of the mitochondrial ATPase. Ackerman SH, Gatti DL, Gellefors P, Douglas MG, Tzagoloff A; FEBS Lett. 1991;278:234-238. PMID:1825065