Key result
Low-pH-dependent membrane fusion is a rare, strain-dependent phenomenon in human metapneumovirus, restricted to some lineage A strains possessing a glycine at position 294.
Acidic pH is not a general trigger for human metapneumovirus F protein-mediated membrane fusion, as low-pH dependency is a rare, strain-dependent phenomenon linked to a specific glycine residue.
Challenges uniform low-pH fusion models for HMPV; leaves open strain-specific entry mechanisms for validation.
Membrane fusion promoted by human metapneumovirus (HMPV) fusion (F) protein was suggested to require low pH (R. M. Schowalter, S. E. Smith, and R. E. Dutch, J. Virol. 80:10931-10941, 2006). Using prototype F proteins representing the four HMPV genetic lineages, we detected low-pH-dependent fusion only with some lineage A proteins and not with lineage B proteins. A glycine at position 294 was found responsible for the low-pH requirement in lineage A proteins. Only 6% of all HMPV lineage A F sequences have 294G, and none of the lineage B sequences have 294G. Thus, acidic pH is not a general trigger of HMPV F proteins for activity.
No takes yet. Share an insight, caveat, or question.
Herfst et al. (2008) studied Human metapneumovirus (HMPV) infection (in vitro model). Low pH exposure (pH 5.0) vs. Neutral pH (pH 7.4) was evaluated on Membrane fusion (assessed by syncytium formation and cell content mixing). Low-pH-dependent membrane fusion is a rare, strain-dependent phenomenon in human metapneumovirus, restricted to some lineage A strains possessing a glycine at position 294.
Synapse has enriched 4 closely related papers on similar clinical questions. Consider them for comparative context: