The mouse disabled 2 interacting protein 2 (mDaIP2) had been obtained through yeast two hybrid system. It consists of 506 amino acids and its calculated molecular weight is 57.7 kDa. The protein contains N-terminal FCH domain and C-terminal SH3 domain. The SH3 domain interacts with the proline rich domain of mDab2 which had been identified to possess a transcriptional activation function. In RA-treated F9 teratocarcinoma cell, the mDaIP2 and mDab2 genes were differentially expressed in a RA-responsive manner and both were detected to localize in cytoplasm and nucleus. Homology search of all NCBI sequences indicated that the amino acid sequence of mDaIP2 shares 82% identity with human NOSTRIN which controls activity, trafficking, and targeting of nitric oxide synthase (eNos). The eNos was not detected in RA-treated F9 cell. These results suggest that mDaIP2 somehow functions in a different fashion from NOSTRIN in F9 cell differentiation and that its function may be concerted with that of mDab2.