Synaptotagmin family member involved in vesicular and membrane trafficking which does not bind Ca(2+). Inhibits clathrin-mediated and bulk endocytosis, functions to ensure precision in vesicle retrieval. Plays an important role in dopamine transmission by regulating endocytosis and the vesicle-recycling process. Essential component of a neuronal vesicular trafficking pathway that differs from the synaptic vesicle trafficking pathway but is crucial for development and synaptic plasticity. In macrophages and microglia, inhibits the conventional cytokine secretion, of at least IL6 and TNF, and phagocytosis. In astrocytes, regulates lysosome exocytosis, mechanism required for the repair of injured astrocyte cell membrane (By similarity). Required for the ATP13A2-mediated regulation of the autophagy-lysosome pathway (PubMed:27278822). Homodimer. Can also form heterodimers. Interacts with PRKN (PubMed:12925569). Interacts (via C2 2 domain) with AGO2 and SND1; the interaction with SND1 is direct. Interacts with KIF1A; the interaction increases in presence of calcium (By similarity). Localized in vesicles that travels in axonal and dendritic shafts in both anterograde and retrograde directions. In macrophages and microglia, recruited in phagosomes at early stages of phagocytosis (By similarity). Found in the core of the Lewy bodies in the brain of sporadic Parkinson disease patients (PubMed:12925569). The second C2 domain/C2B is required for the inhibitory role in both clathrin-mediated and bulk endocytosis. The transmembrane domain and the first C2 domain/C2A are critical for the inhibitory role in clathrin-mediated endocytosis or bulk endocytosis, respectively. Unlike in other synaptotagmin family members, the first C2 domain/C2A does not bind Ca(2+) neither mediates Ca(2+)-dependent phospholipid binding. An aspartate-to-serine substitution in this domain inactivates Ca(2+)/phospho-lipid binding. Ubiquitinated, at least by PRKN, and targeted to the proteasome complex for degradation (PubMed:12925569, PubMed:27278822). Ubiquitination is inhibited by ATP13A2 (PubMed:27278822). Belongs to the synaptotagmin family. Extended N-terminus.