SIII, also known as elongin, is a general transcription elongation factor that increases the RNA polymerase II transcription elongation past template-encoded arresting sites. Subunit A is transcriptionally active and its transcription activity is strongly enhanced by binding to the dimeric complex of the SIII regulatory subunits B and C (elongin BC complex). The elongin BC complex seems to be involved as an adapter protein in the proteasomal degradation of target proteins via different E3 ubiquitin ligase complexes, including the von Hippel-Lindau ubiquitination complex CBC(VHL). By binding to BC-box motifs it seems to link target recruitment subunits, like VHL and members of the SOCS box family, to Cullin/RBX1 modules that activate E2 ubiquitination enzymes.
Detection of TCEB2 in Immunoprecipitates of Jurkat whole cell lysate (1 mg for IP, 20% of IP loaded) using ab168836 at 6 µg/mg lysate for IP (Lane 1) and at 1 µg/ml for subsequent Western blot detection. Lane 2 represents control IgG IP. Detection: Chemiluminescence with an exposure time of 3 minutes.