Plays a role in virus entry by participating in host receptor binding at the cell surface. Interacts with isoform gQ2. Associates with the glycoprotein complex gH-gL (PubMed:12551983, PubMed:15254169). The gH/gL/gQ1/gQ2 complex binds to human receptor CD46 (PubMed:24215487). Glycosylated by host. Transcribed from a highly spliced mRNA.