Exosome RNA helicase Mtr4 (Mtr4)

Exosome RNA helicase Mtr4 is an **ATP-dependent Ski2-like RNA helicase** that acts as a central cofactor and regulator of the nuclear RNA exosome complex[1][2][4]. It is essential for **nuclear RNA surveillance and degradation**, recruiting, unwinding, and delivering RNA substrates—such as pre-rRNAs, defective mRNAs, and other non-coding RNAs—for 3′–5′ exonucleolytic decay[2][3][4]. Mtr4 has a conserved helicase core with two RecA-like domains, a winged-helix domain, and a helical bundle domain, plus a unique arch domain critical for rRNA processing and adaptor protein binding[1][2]. Mtr4 operates as part of the **TRAMP complex** in partnership with poly(A) polymerases and RNA-binding proteins, facilitating the surveillance of aberrant or unnecessary RNAs in eukaryotic cells[2]. Besides its canonical helicase activity, it participates in broader regulatory and quality-control mechanisms for gene expression and RNA metabolism. There are currently no drugs directly targeting Mtr4 in clinical use, but it remains of significant interest in the context of RNA turnover-associated diseases and fundamental cell biology.

Other names

MTREXDOB1KIAA0052SKIV2L2fSAP118ATP-dependent RNA helicase DOB1ATP-dependent RNA helicase SKIV2L2TRAMP-like complex helicasefunctional spliceosome-associated protein 118Superkiller viralicidic activity 2-like 2

ATP-dependent unwinding of RNA to facilitate exosome-mediated 3′–5′ RNA decay Presentation and threading of RNA substrates to the exosome for further degradation Bridging RNA substrate recognition by adaptor complexes (e.g., TRAMP, NEXT) to degradation by the exosome