PXN and neuroblastoma: Furthermore, although paxillin phosphorylation at S273 reportedly blocks NES activity and facilitates its nuclear transport in fibroblasts (Dong et al, 2009), we found that paxillin phosphorylated at S273 was predominantly cytoplasmic in primary cultured neurons, although it became transiently nuclear in neuroblastoma N2a cells in non-mitotic phases of the cell cycle.