Nonselective ligand-gated cation channel probably playing a role in the regulation of membrane trafficking events. Acts as a Ca(2+)-permeable cation channel with inwardly rectifying activity (  ). Mediates release of Ca(2+) from endosomes to the cytoplasm, contributes to endosomal acidification and is involved in the regulation of membrane trafficking and fusion in the endosomal pathway . Does not seem to act as mechanosensory transduction channel in inner ear sensory hair cells. Proposed to play a critical role at the cochlear stereocilia ankle-link region during hair-bundle growth (By similarity). Involved in the regulation of autophagy . Through association with GABARAPL2 may be involved in autophagosome formation possibly providing Ca(2+) for the fusion process (By similarity). Through a possible and probably tissue-specific heteromerization with MCOLN1 may be at least in part involved in many lysosome-dependent cellular events . Possible heteromeric ion channel assemblies with TRPV5 show pharmacological similarity with TRPML3 .
Subcellular locations: Cell membrane, Early endosome membrane, Late endosome membrane, Lysosome membrane, Cytoplasmic vesicle, Autophagosome membrane
Recycles between the plasma membrane and intracellular compartments by a dynamin-dependent endocytic pathway . Under normal conditions, only a very minor proportion is present at the cell membrane . In the cochlea located at the base of stereocilia near the position of the ankle links (By similarity).