TAF II p105, also called TAF4B, is a celltype specific transcriptional co-activator that is a component of the TFIID complex. Expressed primarily in B cells and ovarian granulosa cells, TAF II p105 can interact with OCBA/POU2AF1 to activate B cell-specific octamerdependent transcription. Additionally, TAF II p105 plays an important role in co-activating the transcription factor NFkB and is essential for activation of anti-apoptotic genes such as TNFAIP3. TAF II p135, also known as TAF4, TAF2C, TAF2C1, TAF4A or TAFII130, is a 1,085 amino acid subunit of TFIID that accelerates transcriptional activation triggered by thyroid hormone (TR) or retinoic acid (RA). Localized to the nucleus, TAF II p135 contains one TAFH domain and is thought to bind to proteins that contain glutamine-rich domains, such as the transcription factor CREB.