Seems to be involved in cell adhesion through trans-homophilic and -heterophilic interactions, the latter including specifically interactions with PVRL2/nectin-1. Does not act as receptor for alpha-herpesvirus entry into cells.

Predominantly expressed in placenta. Not detected in normal breast epithelium but expressed in breast carcinoma.

Defects in PVRL4 are the cause of ectodermal dysplasia-syndactyly syndrome type 1 (EDSS1) [MIM:613573]. EDSS1 is a form of ectodermal dysplasia, a heterogeneous group of disorders due to abnormal development of two or more ectodermal structures. EDSS1 is characterized by the association of hair and teeth abnormalities with cutaneous syndactyly of the hands and/or feet. Hair morphologic abnormalities include twists at irregular intervals (pilli torti) and swelling along the shafts, particularly associated with areas of breakage. Dental findings consist of abnormally widely spaced teeth, with peg-shaped and conical crowns. Patients have normal sweating.

Belongs to the nectin family.
Contains 2 Ig-like C2-type (immunoglobulin-like) domains.
Contains 1 Ig-like V-type (immunoglobulin-like) domain.

The soluble form is produced by proteolytic cleavage at the cell surface (shedding), probably by ADAM17/TACE.

Cell membrane. Cell junction > adherens junction. Colocalizes with MLLT4 at cadherin-based adherens junctions and Secreted. The secreted form is found in breast tumor patients.