Interferon induced transmembrane protein-1 (IFITM1) is one of transmembrane protein which is differentially expressed in uterus during estrus cycle and pregnancy, that IFITM1 gene is highly expressed in estrus stage by the effect of estrogen, and in parturition by the effect of PGF2 alpha. This genes are also up-regulated in cells with hyperactivation of the WNT/β-catenin signaling pathway. In this study, to identify a function of IFITM1, the binding partner of IFITM1 were determined using immunoprecipitation and LC- MASSMASS methods. 1, 3 and 5 ug of polyclonal anti-IFITM1 antisera were used for immunoprecipitation, and the 75 kDa of specific band was detected in silver stained polyacylamide gel. This band were chracterized using LC-MASS-MASS, and revealed this band is glucose regulated protein 75 (GRP75) which binds to p53 and inhibits the p53 action in nucleus. To identify the localization of GRP75 in cells, immunocytochemical approach has been applied, and GRP75 is expressed in mitochondria of L929 murine connective tissue cells. Co-localization study between IFITM1 and GRP75 in L929 cell identified that these two proteins were closely expressed in mitochondria. Although the role of the interaction of these two protein need to be clarified in various biological phenomena, this data suggest that close interaction of IFITM1 and GRP75 may regulate cellular functions in uterus on sets of estrus cycle and pregnancy.

A member of mice interferon inducible transmembrane protein like family, IFITM1, is reported to play an important role in primordial germ cell (PGC) formation and this protein reported for anti‐proliferation. This study conducted to investigate the mIFITM1 expression in reproductive organs of male mice. mIFITM1 expression in testis and epididymis were revealed by immunostaining and immuno blot. Moreover, we showed that mIFITM1 is related to development of mouse testis. mIFITM1 protein expression as markedly upregulated around 5‐ 15day after birth in testis, but postnatal 21 56 day detected pattern was decreasing by immunoblot. In the other reproductive organ, epididymis, we observed that mIFITM1 protein was strongly expressed in caput, corpus and cauda. We analyzed IFITM1 gene expression under conditions of androgen manipulation. Total RNAs were obtained from the epididymis of adult mice that castrated and injected. Testosterone replacement for animals 7day after surgery. In castrated animals, A clear decrease was found in the IFITM1 protein level on Interestingly, castrated mice was revealed that mIFITM1 expression is strong. At that time, the injected catration mice decrease in IFITM1 gene expression. We also found same result from the immunoblot analysis. Our data suggest that the function of the IFITM1 expression in sperm is remain unclear but mIFITM1 expression will be important to postnatal development of mice testis and spermatogenesis. Also, mIFITM1 regulated not only sexual maturation by gene expression in the reproductive organs but also by hormone.