Fyn-induced phosphorylation of β-adducin at tyrosine 489 and its role in their subcellular localization

Fyn is a Src-family tyrosine kinase involved in neuronal development, transmission, and plasticity in mammalian central nervous system. We have previously reported that Fyn binds to a cytoskeletal protein, β-adducin, in a phosphorylation-dependent manner. In the present report, we show that Fyn phosphorylates β-adducin at tyrosine 489 located in its C-terminal tail domain. Phosphorylation of β-adducin at Y489 was required for its association with the Fyn-SH2 domain. An antibody specific to the phosphorylated form of β-adducin was raised in rabbits and showed that Y489 of β-adducin was phosphorylated in wild type, but not in Fyn(−/−) mice, suggesting that Y489 of β-adducin is phosphorylated downstream of Fyn in vivo. After phosphorylation at Y489, β-adducin was translocated to the cell periphery, and colocalized with Fyn. These results suggest that Fyn phosphorylates and binds to β-adducin at Y489, resulting in translocation of β-adducin to the Fyn-enriched regions in the plasma membrane.