?
 
NOPS domain, including C-terminal coiled-coil region, in paraspeckle protein component 1 (PSPC1) and similar proteins The family contains a DBHS domain (for Drosophila behavior, human splicing), which comprises two conserved RNA recognition motifs (RRMs), also termed RBDs (RNA binding domains) or RNPs (ribonucleoprotein domains), and a charged protein-protein interaction NOPS (NONA and PSP1) domain. This model corresponds to the NOPS domain, with a long helical C-terminal extension, of paraspeckle component 1 (PSPC1, also termed PSP1), a novel nucleolar factor that accumulates within a new nucleoplasmic compartment, termed paraspeckles, and diffusely distributes in the nucleoplasm. It is ubiquitously expressed and highly conserved in vertebrates. Although its cellular function remains unknown currently, PSPC1 forms a novel heterodimer with the nuclear protein p54nrb, also known as non-POU domain-containing octamer-binding protein (NONO), which localizes to paraspeckles in an RNA-dependent manner. The NOPS domain specifically binds to the second RNA recognition motif (RRM2) domain of the partner DBHS protein via a substantial interaction surface. Its highly conserved C-terminal residues are critical for functional DBHS dimerization while the highly conserved C-terminal helical extension, forming a right-handed antiparallel heterodimeric coiled-coil, is essential for localization of these proteins to subnuclear bodies. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",