Human T-lymphotropic virus 2 envelope glycoprotein gp21 (gp21) (gp21)

Human T-lymphotropic virus 2 envelope glycoprotein gp21 is the transmembrane (TM) subunit of the viral envelope complex, essential for the infection process of HTLV-2 (UniProt, 2024). It is synthesized as part of a larger precursor, gp63, which is subsequently cleaved by host cell proteases into the surface subunit (gp46) and the transmembrane subunit (gp21) (UniProt, 2024). The primary biological function of gp21 is to mediate the fusion of the viral envelope with the host cell plasma membrane, a process triggered by the binding of gp46 to cellular receptors such as GLUT1 and neuropilin-1 (Frontiers in Microbiology, 2012; Wikipedia, 2024). Structurally, gp21 is a class I viral fusion protein that undergoes significant conformational changes, forming a six-helix bundle that brings the viral and cellular membranes into close proximity (PNAS, 2000). Although HTLV-2 is generally considered to have lower pathogenicity than HTLV-1, it has been associated with rare cases of neurological disease and was originally identified in patients with hairy cell leukemia (MDPI, 2022; Wikipedia, 2024). As a critical component of the viral entry machinery, gp21 represents a potential therapeutic target for fusion inhibitors, similar to those developed for HIV-1 (PNAS, 2000). Currently, gp21 is primarily utilized as an immunodominant antigen in diagnostic assays to confirm HTLV-2 infection and differentiate it from HTLV-1 (Journal of Clinical Microbiology, 2001). The high degree of conservation in the fusion domain of gp21 across different HTLV strains makes it an attractive target for broad-spectrum anti-retroviral development (PNAS, 2000).

Other names

Human T-cell leukemia virus 2 envelope glycoprotein gp21Transmembrane protein gp21TMHTLV-2 gp21Envelope glycoprotein gp63

Fusion inhibition