PPxY

PPxY is a short amino acid sequence motif commonly found in protein interactions within various biological processes. The motif consists of the amino acids proline (P), proline (P), any amino acid (x), and tyrosine (Y), where 'x' represents any residue. This sequence plays a significant role in mediating protein-protein interactions, especially in cellular signaling, trafficking, and structural functions.

The PPxY motif is predominantly recognized by WW domains, which are small protein modules that specifically bind proline-rich sequences. The interaction between WW domains and PPxY motifs is crucial for recruiting proteins to specific cellular locations or forming signaling complexes. For example, the motif is involved in the regulation of the Hippo pathway, a key signaling pathway that controls cell proliferation and apoptosis, by facilitating interactions between pathway components.

In viral biology, the PPxY motif is noted for its role in the lifecycle of some viruses, where it can mediate interactions between viral proteins and host cellular factors. This can influence processes such as viralAssembly, budding, or evasion of immune responses.

From a structural perspective, the PPxY motif often resides in disordered regions of proteins, allowing flexible interactions with WW domains or other proline-binding modules. Its conserved nature across species and proteins underscores its functional importance in cellular regulation.

Research on PPxY continues to illuminate its diverse roles across biological systems, emphasizing its relevance in health, disease, and therapeutic development. The motif remains a focus for understanding protein interaction networks and designing targeted interventions in diseases where these interactions are dysregulated.