sentences:  The CIITA protein contains an acidic transcriptional activation domain, 4 LRRs (leucine-rich repeats) and a GTP binding domain.The protein uses GTP binding to facilitate its own transport into the nucleus.Once in the nucleus, the protein acts as a positive regulator of class II major histocompatibility complex gene transcription, and is often referred to as the "master control factor" for the expression of these genes.