Filamin A is required in injured axons for HDAC5 activity and axon regeneration [Cell Biology]

July 8th, 2015 by Cho, Y., Park, D., Cavalli, V.

Microtubule dynamics are important for axon growth during development as well as axon regeneration after injury. We previously identified HDAC5 as an injury-regulated tubulin deacetylase that functions at the injury site to promote axon regeneration. However, the mechanisms involved in the spatial control of HDAC5 activity remain poorly understood. Here we reveal that HDAC5 interacts with the actin binding protein filamin A via its C-terminal domain. Filamin A plays critical roles for HDAC5-dependent tubulin deacetylation since in cells lacking filamin A, levels of acetylated tubulin are markedly elevated. We found that nerve injury increases filamin A axonal expression in a protein synthesis dependent manner. Reducing filamin A levels or interfering with the interaction between HDAC5 and filamin A prevents injury-induced tubulin deacetylation as well as HDAC5 localization at the injured axon tips. In addition, neurons lacking filamin A display reduced axon regeneration. Our findings suggest a model in which filamin A local translation following axon injury controls localized HDAC5 activity to promote axon regeneration