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Receptor Name
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Transient receptor potential cation channel, mucolipin subfamily, member 1
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Nonselective cation channel probably playing a role in the regulation of membrane trafficking events and of metal homeostasis (PubMed:29019981). Proposed to play a major role in Ca2+ release from late endosome and lysosome vesicles to the cytoplasm, which is important for many lysosome-dependent cellular events, including the fusion and trafficking of these organelles, exocytosis and autophagy. Required for efficient uptake of large particles in macrophages in which Ca2+ release from the lysosomes triggers lysosomal exocytosis. May also play a role in phagosome-lysosome fusion (PubMed:23993788). Involved in lactosylceramide trafficking indicative for a role in the regulation of late endocytic membrane fusion/fission events. By mediating lysosomal Ca2+ release is involved in regulation of mTORC1 signaling and in mTOR/TFEB-dependent lysosomal adaptation to environmental cues such as nutrient levels (PubMed:25733853). Seems to act as lysosomal active oxygen species (ROS) sensor involved in ROS-induced TFEB activation and autophagy (By similarity). Functions as a Fe2+ permeable channel in late endosomes and lysosomes. Proposed to play a role in zinc homeostasis probably implicating its association with TMEM163 (By similarity). In adaptive immunity, TRPML2 and TRPML1 may play redundant roles in the function of the specialized lysosomes of B cells (PubMed:17050035). May contribute to cellular lipase activity within the late endosomal pathway or at the cell surface which may be involved in processes of membrane reshaping and vesiculation, especially the growth of tubular structures. However, it is not known, whether it conveys the enzymatic activity directly, or merely facilitates the activity of an associated phospholipase.
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Channel activity is controlled by multiple regulatory mechanisms in different subcellular compartments (By similarity). Channel function is transiently modulated by changes in Ca2+, and inhibited by a reduction of pH; pH changes modify the aggregation state of unitary channels; a negative cooperativity between extracellular/lumenal Ca2+ and H+ is suggested (PubMed:29019981). Regulated by phosphoinositides in a compartment-specific manner: in lysosomes activated by PtdIns(3,5)P2 (Phosphatidylinositol 3,5-bisphosphate) and at the plasma membrane inhibited by PtdIns(4,5)P2 (Phosphatidylinositol 4,5-bisphosphate) (PubMed:29019981).
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