Identification of Potential Partners of Matrix-Remodeling Associated 7 (MXRA7) in Murine Liver

The functions of matrix-remodeling associated 7 (MXRA7) gene or its protein products remained largely unknown at all levels in either human or other animals, until recent studies revealed involvement of this gene in eye development or liver disease models. In this paper, we described that yeast-two-hybrid screening on MXRA7 with a murine liver cDNA library disclosed 23 proteins (MUP1, Cpt1a, Mat1a, aldh1l1, Cytb, H2-K1, Psmb1, marc2, Atp5j2, Sec24D, Trf, Rdh7, Apoe, Glud1, Gmfb, Alb, Hdlbp, Pzp, Etnk2, Nrn1, Serpina1a, Apoa2 and GNMT) that probably interact with MXRA7 proteins directly or indirectly. Among them, MUP1 or others in the same family, accounted for one sixth of all candidate clones. Therefore, MUP1 was the most possible partner of MXRA7 proteins. When a murine hepatoma cell line was transfected to overexpress MXRA7 and MUP1 simultaneously, immunofluorescence and pull-down assay indicated that these two proteins co-localized in the cells or coexisted in the same complexes in cell lysates. Furthermore, recombinant MXRA7 proteins and MUP1 can form complexes directly in absence of any other proteins. In conclusion, MXRA7 proteins in murine livers might interact with metabolism-related proteins such as MUP1 etc, through which involved in metabolisms in liver.