X-Box Binding Protein 1

**Semantic type:** Amino Acid, Peptide, or Protein

**Definition:** X-box binding protein 1 (261 aa, ~29 kDa) is encoded by the human XBP1 gene. This protein is a bZIP transcription factor that is involved in both the transcription of major histocompatibilty complex class II genes and the response to unfolded proteins and viral infection.

**Synonyms:** - Tax-Responsive Element-Binding Protein 5 - XBP-1 - XBP1