1-261aa, Full length protein. MW: 40,148 Da. Purity >85% (SDS-PAGE). This gene encodes a transcription factor that regulates MHC class II genes by binding to a promoter element referred to as an X box. This gene product is a bZIP protein, which was also identified as a cellular transcription factor that binds to an enhancer in the promoter of the T cell leukemia virus type 1 promoter. It may increase expression of viral proteins by acting as the DNA binding partner of a viral transactivator. It
[X-box-binding protein 1 isoform XBP1(S); X-box-binding protein 1; X-box-binding protein 1; X-box binding protein 1; Tax-responsive element-binding protein 5]