This family represents the N-terminal region of the Drosophila specific Methuselah protein. Drosophila Methuselah (Mth) mutants have a 35% increase in average lifespan and increased resistance to several forms of stress, including heat, starvation, and oxidative damage. The protein affected by this mutation is related to G protein-coupled receptors of the secretin receptor family. Mth, like secretin receptor family members, has a large N-terminal ectodomain, which may constitute the ligand binding site. This family is found in conjunction with pfam00002.