Function
An essential component of the GATOR subcomplex GATOR1 which functions as an inhibitor of the amino acid-sensing branch of the TORC1 signaling pathway (PubMed:23723238, PubMed:27166823, PubMed:25512509). The two GATOR subcomplexes, GATOR1 and GATOR2, regulate the TORC1 pathway in order to mediate metabolic homeostasis, female gametogenesis and the response to amino acid limitation and complete starvation (PubMed:23723238, PubMed:27166823, PubMed:25512509). The function of GATOR1 in negatively regulating the TORC1 pathway is essential for maintaining baseline levels of TORC1 activity under nutrient rich conditions, and for promoting survival during amino acid or complete starvation by inhibiting TORC1-dependent cell growth and promoting catabolic metabolism and autophagy (PubMed:23723238, PubMed:27166823). In addition, this inhibition of TORC1 is necessary to maintain female fertility under normal conditions and during periods of nutrient stress (PubMed:24786828, PubMed:27672113, PubMed:25512509). GATOR1 and GATOR2 act at different stages of oogenesis to regulate TORC1 in order to control meiotic entry and promote oocyte growth and development (PubMed:25512509). After exactly four mitotic cyst divisions, the GATOR1 complex members (Iml1, Nprl2 and Nprl3) down-regulate TORC1 to slow cellular metabolism and promote the mitotic/meiotic transition (PubMed:25512509). At later stages of oogenesis, the mio and Nup44A components of the GATOR2 complex inhibit GATOR1 and thus activate TORC1 to promote meiotic progression, and drive oocyte growth and development (PubMed:25512509).
Sequence
MHSHTNETAATSTTAGAVTNGAGGSGAGAAGAHGSTEGKIRCIFLSEFHATAGCKISCQVPDNYISKDVFDAINVYIIPKQHLQRCILTVNAMDVKIVGYPVGIQDQQKYARNAFLFNLCFVCDSRARSVQYEPVVKKLSEYLIMMEEESCFLSREDDKRRLQNIFETVLRDLNERKVATIVEGDNTIYLKIVMHKPDPPPVKDHMVPLLLANLRDAPLDNWDLTTQQILPYINGINHVARIAAEADVETDLVKSCIQNLVYYGVVQLLPILKYSNVYMTQNLKHLIQSASLSGACRKYVALRPDKTLPSVQRIFQFYASMTHGVTLRAICQRLCPQHHNIDERRMVIFGLQHRFIRCIHKYPVFTGSVPSGRQKMYTGLISFDEICCKTGLSPCTIERDIEKDTNVTVIWK