May function in transferrin receptor internalization at the plasma membrane through a cargo-specific control of clathrin-mediated endocytosis. Alternatively, may act as a negative regulator of the amino acid-induced TOR signaling by inhibiting the formation of active Rag GTPase complexes. Preferentially binds inactive Rag GTPase complexes and prevents their interaction with the mTORC1 complex inhibiting its relocalization to lysosomes and its activation. Thereby, may indirectly regulate cell growth, proliferation and autophagy.
Subcellular locations: Membrane, Clathrin-coated pit, Cytoplasmic vesicle, Clathrin-coated vesicle, Nucleus
Specifically associated with transferrin receptor-containing clathrin-coated pits and clathrin-coated vesicles. May also localize to the nucleus.
Expressed in all tissues tested with higher expression in pancreas. Expressed by retinal pigment epithelial cells (at protein level).