3.1.3 Integrins
Recently, Sigrist et al suggested that 2019-nCoV may also use integrins
as cell receptors in host cells, binding to them through a conserved RGD
(403–405: Arg-Gly-Asp) motif in receptor-binding domain of S protein
that is absent from other coronaviruses (Sigrist et al., 2020). The
conformational changes due to ACE2 binding expose the RGD containing
region. Different viruses like Ebola virus (Schornberg et al., 2009),
human papillomavirus (Yoon et al., 2001), HIV-1 (Monini et al., 2012)
and EBV (Tugizov et al., 2003) use integrins for cell attachment or
entry. The antibody natalizumab (α4β1/β7 integrin antagonist) for the
treatment of multiple sclerosis/Crohn’s disease and the small molecule
tirofiban (αIIbβ3 inhibitor) for the treatment of acute coronary
syndrome are the known inhibitors of integrin (Ley et al., 2016). These
studies confirm that inhibiting the integrin scan impede some
coronaviruses from entering the host cells is considered as a prolific
target for antiviral drug discovery.