QKI Protein, Human (His, Strep)

QKI is an RNA reader protein that recognizes and binds specific RNAs, regulating RNA metabolic processes such as pre-mRNA splicing, circular RNA (circRNA) formation, mRNA export, mRNA stability, and/or translation. It is involved in various cellular processes, including mRNA storage into stress granules, apoptosis, lipid deposition, interferon response, glial cell fate, and development. QKI binds to the 5'-NACUAAY-N(1,20)-UAAY-3' RNA core sequence and acts as an mRNA modification reader, specifically recognizing and binding mRNA transcripts modified by internal N(7)-methylguanine (m7G). During epithelial to mesenchymal transition and in cardiomyocytes, QKI promotes the formation of circRNAs by binding to sites flanking circRNA-forming exons, which are produced by back-splicing circularization of pre-mRNAs. QKI plays a central role in myelination through three distinct mechanisms: 1) protecting and stabilizing target mRNAs (e.g., MBP, SIRT2, and CDKN1B) to promote oligodendrocyte differentiation (by similarity); 2) regulating the nuclear export of MBP mRNA for mRNA transport (by similarity); and 3) indirectly regulating MAG pre-mRNA splicing during oligodendrocyte differentiation by binding to HNRNPA1 mRNA splicing factor (by similarity). It also regulates microexon alternative splicing of the Rho GTPase pathway in microglia differentiation and remyelination (by similarity) and promotes monocyte differentiation by regulating pre-mRNA splicing in naive peripheral blood monocytes. QKI is a key regulator of muscle development, maintaining cardiomyocyte contractile function by regulating alternative splicing of cardiomyocyte transcripts (by similarity), while suppressing thermogenesis by reducing the stability, nuclear export, and translation of PPARGC1A and UCP1 mRNAs (by similarity). Additionally, QKI is involved in visceral endoderm function, blood vessel development (by similarity), and may contribute to smooth muscle development. Beyond its RNA-binding activity, QKI acts as a nuclear transcription coactivator for SREBF2/SREBP2 (by similarity).