Essential for gut mitochondrial activity. Might be involved in tissue specific growth factor production. Component of the mitochondrial ribosome small subunit (28S) which comprises a 12S rRNA and about 30 distinct proteins. Expressed in anterior and posterior midgut primordia in stage 11 embryos. In stage 13 embryos, expression is high in the developing midgut and hindgut. In stage 16 embryos, expression is elevated in the midgut, hindgut, and in a small region that will give rise to pharyngeal muscles and to the stomatogastric nervous system. In larvae, expression is predominant in the gut, and head, presumably in pharyngeal muscles. Expressed both maternally and zygotically throughout development, lowest levels are in third larval instar and pupae. Mutants exhibit a strong systemic growth defect and die before reaching wild-type size. Belongs to the universal ribosomal protein uS15 family.