Post-translational modification networks as master regulators of influenza virus replication, host adaptation, and immune evasion.

Influenza viruses remain major global health threats due to their rapid evolution and complex interactions with host regulatory systems. While genetic variation is a key driver of viral pathogenicity and host adaptation, growing evidence indicates that post-translational modifications (PTMs) provide an additional regulatory layer that can influence viral replication, immune evasion, and metabolic remodeling. In this review, we synthesize current knowledge on how coordinated PTM networks, including phosphorylation, ubiquitination, SUMOylation, glycosylation, acetylation, lipidation, and RNA methylation, are implicated across multiple stages of the influenza virus life cycle. Accumulating studies indicate that phosphorylation and ubiquitin signaling can fine-tune polymerase activity and ribonucleoprotein trafficking, whereas SUMOylation and acetylation modulate polymerase function and host immune antagonism. Glycosylation remodeling of viral glycoproteins is closely associated with antigenic evolution and immune escape, while epitranscriptomic RNA methylation and PTM-linked metabolic pathways reshape host environments in ways that may support replication. Notably, many mechanistic insights derive from cell-based or model organism systems, and the relative contribution of specific PTM events during human infection remains incompletely defined. A systems-level view of PTM networks highlights emerging regulatory vulnerabilities at the host-virus interface and supports further evaluation of PTM-modulating enzymes as potential targets for host-directed antiviral and vaccine strategies.