QKI is a member of the signal transduction and activator of RNA (STAR) protein family of RNA-binding proteins. Mutations in the mouse Qki locus results in impaired myelin formation resulting in tremors. QKI proteins exist as homodimers, and disruption of the dimerization process is lethal in mice. QKI exists in different isoforms that differ in their C-terminus, resulting in unique subcellular localizations. The nuclear isoform of QKI, QKI-5, is involved in regulation of alternative splicing of MAG mRNA, which encodes for a protein important for myelin sheath formation and maintenance. QKI has also been implicated in schizophrenia and oligodendrocyte differentiation. QKI can function as a tumor suppressor, as it is regulated by p53 to stabilize miRNAs that regulate TGF-β signaling.
