InterPro domain: IPR039896

Protein RED (also known as IK) is found in the nucleus and is a component of the spliceosome [ 1 ]. It is also associated with the spindle pole where it co-localizes with and interacts with the spindle assembly checkpoint protein MAD1 during metaphase and anaphase. Depletion of RED shortens the mitotic cycle and MAD1 is incorrectly localized [ 2 ].

Proteins in this entry also include SPBC1539.02 from the fission yeast and smu-2 from C. elegans. SPBC1539.02 is required for chromosome segregation during meiosis [ 3 ]. SMU-2 and SMU-1 bind to each other as components of the spliceosome and modulate splice site selection of many pre-mRNAs [ 4 ].

Protein RED and related proteins contain an arginine/glutamic acid/aspartic acid repetitive sequence. The region in question has several conserved NLS sequences and a putative trimeric coiled-coil region, indicative that these proteins are expressed in the nucleus [ 5 ].

1. Cryo-EM Structure of a Pre-catalytic Human Spliceosome Primed for Activation. Cell 170, 701-713.e11
2. RED, a spindle pole-associated protein, is required for kinetochore localization of MAD1, mitotic progression, and activation of the spindle assembly checkpoint. J. Biol. Chem. 287, 11704-16
3. Novel genes required for meiotic chromosome segregation are identified by a high-throughput knockout screen in fission yeast. Curr. Biol. 15, 1663-9
4. SMU-2 and SMU-1, Caenorhabditis elegans homologs of mammalian spliceosome-associated proteins RED and fSAP57, work together to affect splice site choice. Mol. Cell. Biol. 24, 6811-23
5. Isolation, sequencing and expression of RED, a novel human gene encoding an acidic-basic dipeptide repeat. Gene 230, 145-54