Also Known as
ELOB_HUMAN, ELOB, TCEB2
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) (PubMed:7638163). In embryonic stem cells, the elongin BC complex is recruited by EPOP to Polycomb group (PcG) target genes in order generate genomic region that display both active and repressive chromatin properties, an important feature of pluripotent stem cells., 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. Heterotrimer of an A (ELOA, ELOA2 or ELOA3), ELOB and ELOC subunit (PubMed:10205047, PubMed:17997974). The elongin BC complex interacts with EPOP; leading to recruit the elongin BC complex to Polycomb group (PcG) target genes, thereby restricting excessive activity of the PRC2/EED-EZH2 complex (By similarity). Part of E3 ubiquitin ligase complexes with CUL5 or CUL2, RBX1 and a substrate adapter protein that can be either SOCS1, SOCS5, ELOA, VHL or WSB1 (PubMed:15590694, PubMed:22286099). Interacts with VHL (PubMed:10205047, PubMed:11006129). Found in a complex composed of LIMD1, VHL, EGLN1/PHD2, ELOB and CUL2. Interacts with SPSB1 (PubMed:17189197). Interacts with KLHDC10; which may be an E3 ubiquitin ligase complex substrate recognition component (PubMed:23102700).