Anti-HACE1 (Internal) monoclonal antibody, clone 4B22.2

Neuroblastoma is a common fatal pediatric cancer of the developing sympathetic nervous system, which accounts for similar to 10% of all pediatric cancer deaths. To investigate genetic risk factors related to neuroblastoma, many genome-wide association studies have been performed, and single nucleotide polymorphisms (SNPs) within HACE1 gene have been identified to associate with neuroblastoma risk. However, the association of the HACE1 SNPs with neuroblastoma needs to be validated in Southern Chinese children. We genotyped five SNPs located in the HACE1 gene (rs4336470 C>T, rs9404576 T>G, rs4079063 A>G, rs2499663 T>C, and rs2499667 A>G) in 256 Southern Chinese patients in comparison with 531 ethnically matched healthy controls. Single locus analysis showed no significant association between any of HACE1 SNPs and neuroblastoma risk in Southern Chinese children. However, when all the risk genotypes were combined, we found a borderline significant trend toward an increased neuroblastoma risk with 4-5 risk genotypes (adjusted odds ratio = 1.36, 95% confidence interval = 0.98-1.89, P=0.065). Moreover, stratified analysis found that carriers of 4-5 risk genotypes tended to develop neuroblastoma in the retroperitoneal region and have more aggressive tumors, progressing to advanced clinical stages III/IV, when compared with those of 0-3 risk genotypes. In conclusion, HACE1 gene may have weak effect on neuroblastoma risk in Southern Chinese children. Large well-designed studies are needed to strengthen our findings.

Partitioning of the Golgi membrane into daughter cells during mammalian cell division occurs through a unique disassembly and reassembly process that is regulated by ubiquitination. However, the identity of the ubiquitin ligase is unknown. Here we show that the Homologous to the E6-AP Carboxyl Terminus (HECT) domain containing ubiquitin ligase HACE1 is targeted to the Golgi membrane through interactions with Rab proteins. The ubiquitin ligase activity of HACE1 in mitotic Golgi disassembly is required for subsequent postmitotic Golgi membrane fusion. Depletion of HACE1 using small interfering RNAs or expression of an inactive HACE1 mutant protein in cells impaired postmitotic Golgi membrane fusion. The identification of HACE1 as a Golgi-localized ubiquitin ligase provides evidence that ubiquitin has a critical role in Golgi biogenesis during the cell cycle.