Tumor Suppressor Candidate 4 (TUSC4)

NPR2L is a candidate for functional tumor suppressor gene studies.The deduced 380-amino acid conserved soluble protein, which is 97% identical to the mouse protein and orthologous to the yeast nitrogen permease gene Npr2, contains a bipartite nuclear localization signal and a granulin protein-binding domain. The authors identified multiple NPR2L splice variants. Northern blot analysis revealed expression of a 1.5-kb transcript that was most abundant in skeletal muscle, followed by brain, liver, and pancreas, with lower amounts in lung, kidney, placenta, and heart. NPR2L was expressed in most lung cancer cell lines tested. Mutations, including stop mutations, were found in approximately 5% of cell lines tested, but none of the genes identified in the search had a high frequency of mutations.