Regulates the morphogenesis and endocytosis of caveolae (By similarity). Lipid-binding protein that is able to promote the tubulation of the phosphatidic acid-containing membranes it preferentially binds. Plays a role in intracellular vesicle-mediated transport. Involved in the endocytosis of cell-surface receptors like the EGF receptor, contributing to its internalization in the absence of EGF stimulus. (Microbial infection) Specifically enhances the efficiency of HIV-1 virion spread by cell-to-cell transfer (PubMed:29891700). Also promotes the protrusion engulfment during cell-to-cell spread of bacterial pathogens like Listeria monocytogenes (PubMed:31242077). Involved in lipid droplet formation, which is important for HCV virion assembly (PubMed:31801866). Homodimer (By similarity). May form heterooligomers with other PACSINs (By similarity). Interacts (via NPF motifs) with EHD1 (via EH domain) (PubMed:23596323). Interacts (via NPF motifs) with EHD2 (via EH domain); this interaction probably stabilizes the caveolae (PubMed:22323287). Interacts with EHD3 (PubMed:23596323). Interacts (via the SH3 domain) with MICALL1 (PubMed:23596323). Interacts with RAC1 (PubMed:21693584). Interacts (via SH3 domain) with DNM1, SYN1, SYNJ1 and WASL (By similarity). Interacts (via F-BAR domain) with CAV1 (By similarity). Interacts with TRPV4 (By similarity). (Microbial infection) Interacts with ubiquitinated HIV-1 gag (via p6-gag domain); this interaction allows PACSIN2 recruitment to viral assembly sites and its subsequent incorporation into virions. (Microbial infection) Interacts (via F-BAR domain) with Rous sarcoma virus p2B; this interaction allows PACSIN2 recruitment to viral assembly sites. (Microbial infection) Interacts (via N-terminus) with Hepatatis C virus (HCV) non-structural protein 5A (via N-terminus); this interaction attenuates protein kinase C alpha (PRKCA)-mediated phosphorylation of PACSIN2 at Ser-313 by disrupting the interaction between PACSIN2 and PRKCA. Detected at the neck of flask-shaped caveolae. Localization to tubular recycling endosomes probably requires interaction with MICALL1 and EHD1. Widely expressed. The F-BAR domain forms a coiled coil and mediates membrane-binding and membrane tubulation (PubMed:19549836). Autoinhibition of these functions is mediated by an interaction between the SH3 and F-BAR domains (PubMed:20188097, PubMed:23236520). The F-Bar domain also mediates the binding to the cell actin cytoskeleton through the interaction with CAV-1 (By similarity). (Microbial infection) The SH3 domain is required for the cell-to-cell spreading of HIV-1 virions. Phosphorylated by casein kinase 2 (CK2). Phosphorylation by PKC probably decreases the membrane binding and tubulation capacities of PACSIN2, thereby modulating the lifetime of caveolae (By similarity). Belongs to the PACSIN family.