Vaccinia virus envelope protein F13 (F13)

Vaccinia virus envelope protein F13, also known as p37, is a 37-kDa membrane-associated protein critical for the formation of wrapped and extracellular forms of the vaccinia virus and related orthopoxviruses (such as monkeypox virus)[2][3]. Located on the inner surface of the extracellular enveloped virus (EEV) outer membrane, F13 mediates envelopment, virion export, and efficient cell-to-cell spread by interacting with host trafficking molecules TIP47 and Rab9, and by exhibiting broad-spectrum lipase (phospholipase) activity essential for membrane wrapping and viral egress[1][2][3][6]. The protein contains conserved motifs and is palmitoylated, facilitating its membrane association[3][6]. F13 is highly conserved among orthopoxviruses and is the validated target of the antiviral drug tecovirimat (ST-246), which disrupts virus release by inhibiting F13 activity[1][2]. There are currently no established biomarkers for direct monitoring of F13 activity during therapy. While safety concerns are minimal due to the absence of human homologs, antiviral resistance linked to F13 mutations is a therapeutic consideration[1][2].

Other names

p37F13F13LF13 envelope protein

Inhibition of viral envelopment and egress by blocking F13 (p37) function, preventing formation and release of extracellular virus[1][2]