Based on limited published evidence, PIERCE2 is a microtubule inner protein essential for ciliary and flagellar function. UniProt annotations indicate PIERCE2 mediates attachment of outer dynein arms to dynein-decorated doublet microtubules in axonemes, which is required for motile cilia beating. GO terms implicate roles in axonemal assembly, cilium movement, flagellated sperm motility, and left/right body symmetry determination. The protein localizes to the axonemal A tubule inner sheath and functions through protein-binding interactions. No peer-reviewed publications directly characterizing PIERCE2 function were identified in the provided search results.