The N8 gene encodes a major 24 kDa protein. The N8 protein is hydrophilic, cytoplasmic and is phosphorylated at serine residue. It can form homodimers or multimers in vitro. The N8 protein is detected at higher levels in lung tumor tissue than its normal counterpart. It is also present at high levels in cells derived from lung, breast, colon, kidney and pancreatic tumors, as well as B-cell, T-cell and myeloid leukemic cell lines. The N8 gene is expressed at a higher level in tissues rich in epithelial cells (kidney, salivary gland, colon, small intestine). Immunohistochemical analyses of the N8 protein in the colon indicated that N8 protein expression is higher in highly-differentiated epithelial cells. It is not detectable in surrounding lamina propria, mucosal and submucosal layers. N8 protein expression is induced in fibroblasts infected with adenoviral E1a gene products which acquired epithelial-like characteristics. The N8 protein may be involved in the formation or development of epithelial cells. It might also be associated with the formation of spheroids in NIH3T3 cells.
