2012 Volume 71 Issue 5 Pages 311-321
In order to elucidate the molecular mechanism of neuroblastoma, differential screening of genes obtained from the cDNA libraries of favorable and unfavorable subsets of primary neuroblastomas (NBLs) has identified a novel gene. The novel gene BMCC1, which is preferably expressed in favorable neuroblastoma, was identified. BMCC1 acts as a pro-apoptotic protein in cells and the BCH domain possesses GAP activity. However, its real function has remained elusive. Yeast two-hybrid screening was used to identify proteins that interact with BMCC1. C-terminal amino acids of BMCC1, which includes the BCH domain, were used as baits in this screen. Subsequent analysis identified the translation elongation factor 1 alpha 1 (EF1A1) as a BMCC1-interacting partner. EF1A1 promotes the GTP-dependent binding of aminoacyl-tRNA to the A-site of ribosomes during protein biosynthesis and there is a possible functional implication for a shift in expression from eEF1A-1 to eEF1A-2 during neuronal development. Thus, EF1A may play a important role in neuronal development. Both GST pull-down assays and immunoprecipitation confirmed the physical interaction between BMCC1 and EF1A1. Immunofluorescence analysis revealed that EF1A1 co-localizes with BMCC1 in the cellular cytosol, which was further supported by cell fractionation and Western blotting. Overexpression of EF1A1 inhibited neurite extension in PC12 cells treated with NGF. Interestingly, knockdown of BMCC1 resulted in enhancement of NGF-induced neurite outgrowth, even in EF1A1-overexpressing PC12 cells. Downstream of the TrkA signaling, EF1A1 prolonged ERK phosphorylation. Furthermore, we demonstrated how the BMCC1/EF1A1 complex controls the differentiation of neuroblastoma cells. Taken together, the BMCC1/EF1A1 complex may play an important role in regulating differentiation of neuroblastomas through the NGF/TrkA signaling pathway.
