Controls cell proliferation acting as a negative regulator of TOR signaling pathway mediated by mTORC1. May act as a tumor suppressor. Association of TMEM127 with the cell membrane is enhanced by inhibition of endocytosis. In the cytoplasm, it colocalizes with markers of early endosomal structures, Golgi apparatus and lysosomes. Widely expressed. Disease susceptibility is associated with variants affecting the gene represented in this entry. Consistent with the observation that mTORC1 signaling regulates cell growth and size in many species, TMEM127 knockdown cells are larger and proliferate at higher rates compared to control cell lines. In contrast, cell proliferation is reduced in cells overexpressing TMEM127 (PubMed:20154675). Belongs to the TMEM127 family.