TFIIIB

Function

• the TFIIIB complex has two activities, alpha & beta
• the TFIIIB-alpha & TFIIIB-beta activities are required for transcription of genes with TFIIIC-bound internal promoters & PSE transcription factor-bound external promoters, respectively
• TFIIIB-alpha inhibits transcription by RNA polymerase 3 via its phosphorylation by CK2
• YY1 facilitates formation of TFIIIB-alpha activity complex

Structure

• the TFIIIB-alpha activity complex is composed of TBP, BDP1, & a complex containing both BRF2 & at least 4 stably associated proteins
• the TFIIIB-beta activity complex is composed of TBP, BDP1, & BRF1

More general terms

• molecular complex
• transcription factor (TF)