Transducin beta-like 1X-related protein 1 (TBLR1) (TBLR1)

Transducin beta-like 1X-related protein 1 (TBLR1), also known as TBL1XR1, is a crucial transcriptional coregulator and a member of the WD40 repeat protein family [UniProt Q9BZK7]. It functions as an integral component of the NCoR (nuclear receptor corepressor) and SMRT (silencing mediator for retinoid and thyroid hormone receptors) complexes, which are essential for regulating gene expression through nuclear receptors [NCBI Gene 79718]. TBLR1 plays a unique role as an exchange factor, facilitating the transition from transcriptional repression to activation by recruiting the 19S proteasome to degrade corepressors in a ligand-dependent manner [PubMed 16543150]. Beyond its role in the NCoR/SMRT complex, TBLR1 acts as an E3 ubiquitin ligase adaptor and modulates key signaling pathways, including Wnt/beta-catenin and NF-kappaB [PubMed 21532585]. In clinical contexts, TBLR1 is frequently implicated in the pathogenesis of various cancers, such as diffuse large B-cell lymphoma (DLBCL), where it is often mutated, and in solid tumors like breast and prostate cancer, where its overexpression correlates with poor prognosis [PubMed 25635005]. Additionally, germline mutations in the TBL1XR1 gene are associated with developmental disorders such as Pierpont syndrome and autism spectrum disorder [PubMed 24123366]. While there are currently no FDA-approved drugs specifically targeting TBLR1, it is an active area of research for the development of small-molecule inhibitors like BC-1215 and PROTAC-based degradation strategies aimed at disrupting its oncogenic signaling [PubMed 25713363].

Other names

TBL1XR1IRA1C21orf7DC42

Acts as a transcriptional exchange factor that recruits the 19S proteasome to degrade corepressors (NCoR and SMRT), thereby facilitating the switch from gene repression to activation [PubMed 16543150].