Component of a heteromeric calcium-permeable ion channel formed by PKD1 and PKD2 that is activated by interaction between PKD1 and a Wnt family member, such as WNT3A and WNT9B. Can also form a functional, homotetrameric ion channel (By similarity). Functions as non-selective, voltage-gated cation channel. Required for normal oscillation of Ca(2+) levels within cilia; these oscillations of the intraciliary Ca(2+) levels can trigger cytoplasmic Ca(2+) signaling cascades (By similarity). May contribute to the release of Ca(2+) stores from the endoplasmic reticulum (By similarity). Plays a role in fluid-flow mechanosensation: forms a complex with pkd1l1 in cilia to facilitate flow detection in left/right patterning (PubMed:21307098). Required for normal specification of the body left-right axis during embryogenesis (PubMed:21307098). Channel activity is regulated by phosphorylation. Channel activity is regulated by intracellular Ca(2+). Homotetramer (By similarity). Heterotetramer with pkd1, giving rise to a complex formed by one pkd1 chain and three pkd2 chains (By similarity). Interacts with pkd1l1. Ubiquitously expressed. Expressed in Kupffer's vesicle, an organ equivalent to the node. The C-terminal coiled-coil domain is involved in oligomerization. The coiled-coil domain binds calcium and undergoes a calcium-induced conformation change (in vitro). Phosphorylated. Phosphorylation is important for protein function; a mutant human construct that lacks the N-terminal phosphorylation sites cannot complement a zebrafish pkd2-deficient mutant. N-glycosylated. The four subunits in a tetramer probably differ in the extent of glycosylation; simultaneous glycosylation of all experimentally validated sites would probably create steric hindrance. Defects in left-right axis patterning. Belongs to the polycystin family.