Roles of neuraminidase in the initial stage of influenza virus infection

The Universal Epitope of Influenza A Viral Neuraminidase Fundamentally Contributes to Enzyme Activity and Viral Replication

“…Indeed, this role is supported by the observation that NA-defective virus or wild type viruses in the presence of NA inhibitors form aggregations on the apical surface of the cells (7)(8)(9). Furthermore, NA has been suggested to play additional roles in viral infection including mucus breakdown, which allows for increased viral diffusion throughout the respiratory tract during infection (10,11) and more recently has been shown to contribute to the entry and fusion of the influenza virus into host cells (12,13). It is also noteworthy that the viral neuraminidase may increase bacterial adherence after viral preincubation, predisposing the patients to secondary bacterial infection (14), which is one of the most common causes of fatality in influenza patients (15,16).…”

Formation of virus-like particles from human cell lines exclusively expressing influenza neuraminidase

“…HA binds to sialic acid receptors on the cell surface and mediates the fusion process (Matrosovich et al, 2006), whereas NA cleaves the terminal sialic acids from the cell-surface glycans to facilitate release of the progeny virus from the host cell and prevent aggregation of virus particles (Bucher & Palese, 1975;Air & Laver, 1989). NA is also essential in the initial stage of virus infection by enhancing HA-mediated fusion (Su et al, 2009), helping the virus to penetrate the mucin barrier protecting the airway epithelium (Matrosovich et al, 2004) and promoting virus entry (Ohuchi et al, 2006). Studies of mutant influenza viruses have previously shown that the cytoplasmic tails of HA and NA contribute to control virus assembly (Zhang et al, 2000) and virus morphology (Jin et al, 1997).…”

Homoisoflavonoids from <i>Caesalpinia sappan</i> Displaying Viral Neuraminidases Inhibition

“…[1][2][3] NA is thought to enhance viral mobility via hydrolysis of the α-(2,3)-or α- (2,6)-glycosidic linkage between a terminal sialic acid (Neu5Ac) residue and its adjacent carbohydrate moiety on the host receptor. [4][5][6] These molecules with terminal Neu5Ac are also the target receptors for viral HA (hemagglutinin), 7) the major surface glycoprotein on the viral particle.…”