CRMP‑5 interacts with actin to regulate neurite outgrowth.

CRMP family proteins (CRMPs) are abundantly expressed in the developing nervous system mediating growth cone guidance, neuronal polarity and axon elongation. CRMP‑5 has been indicated to serve a critical role in neurite outgrowth. However, the detailed mechanisms of how CRMP‑5 regulates neurite outgrowth remain unclear. In the current study, co-immunoprecipitation was used to identify the fact that CRMP‑5 interacted with the actin and tubulin cytoskeleton networks in the growth cones of developing hippocampal neurons. CRMP‑5 exhibited increased affinity towards actin when compared with microtubules. Immunocytochemistry was used to identify the fact that CRMP‑5 colocalized with actin predominantly in the C-domain and T-zone in growth cones. In addition, genetic inhibition of CRMP‑5 by siRNA suppressed the expression of actin, growth cone development and neurite outgrowth. Overexpression of CRMP‑5 promoted the interaction with actin, growth cone development and hippocampal neurite outgrowth. Taken together, these data suggest that CRMP‑5 is able to interact with the actin cytoskeleton network in the growth cone and affect growth cone development and neurite outgrowth via this interaction in developing hippocampal neurons.