Involved in the control of early morphogenesis and patterning of both axial midline structures and the development of neural plate. Plays a role in the regulation of planar cell polarity, particularly in the orientation of stereociliary bundles in the cochlea. Required for polarization and movement of myocardializing cells in the outflow tract and seems to act via RHOA signaling to regulate this process. Required for cell surface localization of FZD3 and FZD6 in the inner ear (PubMed:16495441). Homodimer and heterodimer with Vangl1. Interacts through its C-terminal region with the N-terminal half of DVL1, DVL2 and DVL3. The PDZ domain of DVL1, DVL2 and DVL3 is required for the interaction. Variants Glu-255 and Asn-464 impair interaction with the DVL proteins. Also interacts with the PDZ domains of MAGI3, SCRIB/SCRB1 and FZD3 (PubMed:15195140). Interacts with PRICKLE3 (By similarity). Primarily expressed in the brain and epididymis. Not detected in the cochlea of Lp mice. In the embryo, strongly expressed in the neuroectoderm from the earliest stages of neural induction through the late stages of neural tube closure. Detected in the dorso-ventral axis of the neural tube, but not in the floor plate. Expression is low at day 7 dpc; it peaks at 11 dpc, and it remains strong at 15 dpc and 17 dpc. Also expressed in the cochlear epithelium at days 14.5 dpc and 16.5 dpc. Detected at low levels in the outflow tract myocardium from 9.5 dpc with levels increasing by 11.5 dpc. Defects in Vangl2 are a cause of the loop-tail (Lp) mutant phenotype. Heterozygous Lp mice exhibit a characteristic looped tail, while homozygous embryos show a completely open neural tube in the hindbrain and spinal region, a condition similar to the severe craniorachischisis defect in humans. Homozygotes also have complex cardiovascular defects including double-outlet right ventricle, perimembranous ventricular defects, double-sided aortic arch and associated abnormalities in the aortic arch arteries. Homozygotes show cytoplasmic accumulation of Vangl2 instead of the normal membrane localization, and Rhoa expression, which is detected in the mesenchymal cushion cells adjacent to the outflow tract, is lost in homozygotes. Homozygous embryos typically die shortly before or at birth. Belongs to the Vang family.