Recruits TFIIH to the initiation complex and stimulates the RNA polymerase II C-terminal domain kinase and DNA-dependent ATPase activities of TFIIH. Both TFIIH and TFIIE are required for promoter clearance by RNA polymerase. Tetramer of two alpha and two beta chains. Interacts with TAF6/TAFII80. Interacts with ATF7IP. Interacts with SND1. Belongs to the TFIIE alpha subunit family.