Envelope glycoprotein gp150 (FIV) (Env (FIV))

The **envelope glycoprotein gp150** of FIV is a type I membrane protein synthesized as a polyprotein precursor (Env), which is cleaved into the **surface subunit** (gp95, SU)—which mediates receptor binding—and the **transmembrane subunit** (gp36, TM)—which mediates membrane fusion. The Env protein is essential for viral entry and is a primary determinant of host range, cell tropism, and immune recognition. FIV Env functions similarly to HIV-1 Env, binding to the feline CD134 (OX40) and CXCR4 receptors to trigger conformational changes and fusion of viral and host membranes. The Env protein is the principal target for neutralizing antibodies, forms the basis for FIV serodiagnostic assays, and has been experimentally targeted by fusion inhibitors (peptides) analogous to approved HIV drugs. Notably, the signal peptide of FIV Env also serves as a tetherin antagonist (Fsp), a unique mechanism that blocks host antiviral defenses by preventing the incorporation of tetherin into budding virions.

Other names

Env polyproteinSurface glycoprotein (SU)Transmembrane glycoprotein (TM)gp150 (full-length precursor)gp95 (Surface subunit/SU)gp36 (Transmembrane subunit/TM)

Blockade of envelope-mediated fusion/entry (fusion inhibitors) Neutralization of receptor binding (antibodies/vaccines)