The possible interaction of CDA14 and protein elongation factor 1α

The CDA14, a 45kD protein, is currently annotated as PTX1-like protein or ERGIC 32. Over expressing CDA14 can slow PC11 cell proliferation rate. In HepG2 cells, it had been demonstrated that CDA14 is involved in protein transportation. The knowledge about the protein is very limited and not clarified. The CDA14 and its homologous proteins form a family and are restricted to eukaryotes. In the family, there are no homologous sequences with resolved three-dimensional structure and their functions are difficult to predict. Transcriptional expression of CDA14 in three hepatoma cell lines, Hu7, HCC and HepG2, was lower than normal liver tissue and liver carcinoma tissue. In this study, functional proteomic techniques were utilized in searching the interacting counterpart of CDA14. Several proteins involved in protein translation and folding were selectively precipitated with CDA14 and identified mass spectrometry. Interaction of CDA14 and elongation factor 1α was confirmed by Western blotting and confocal microscopy. Elongation factor 1α is a multiple function protein and involved in several biological mechanisms, including protein synthesis, cell proliferation, apoptosis and tumorigensis. Over-expression of CDA14 down regulated the proliferation of HepG2 cells. These results suggest that CDA14 participated in the elongation factor 1α regulated mechanisms.