RHAU (RNA Helicase associated with AU-rich element, also known as DHX36 or G4R1) is a 114-kDa human RNA helicase of the DEAH-box family of helicases encoded by the DHX36 gene.[1]
Structure edit
Structurally, RHAU is a 1008 amino acid-long modular protein. It consists of a ~440-amino acid helicase core comprising all signature motifs of the DEAH-box family of helicases with N- and C-terminal flanking regions of ~180 and ~380 amino acids, respectively. Like all the DEAH-box proteins, the helicase associated domain is located adjacent to the helicase core region and occupies 75% of the C-terminal region.
Function edit
RHAU exhibits a unique ATP-dependent guanine-quadruplex (G4) resolvase activity and specificity for its substrate in vitro.[2][3] RHAU binds G4-nucleic acid with sub-nanomolar affinity and unwinds G4 structures much more efficiently than double-stranded nucleic acid. Consistent with these biochemical observations, RHAU was also identified as the major source of tetramolecular RNA-resolving activity in HeLa cell lysates.
Previous work showed that RHAU associates with mRNAs and re-localises to stress granules (SGs) upon translational arrest induced by various environmental stresses.[4][5] A region of the first 105 amino acid was shown to be critical for RNA binding and re-localisation to SGs.[4]
References edit
- ^ Abdelhaleem M, Maltais L, Wain H (June 2003). "The human DDX and DHX gene families of putative RNA helicases". Genomics. 81 (6): 618–22. doi:10.1016/S0888-7543(03)00049-1. PMID 12782131.
- ^ Vaughn JP, Creacy SD, Routh ED, et al. (November 2005). "The DEXH protein product of the DHX36 gene is the major source of tetramolecular quadruplex G4-DNA resolving activity in HeLa cell lysates". The Journal of Biological Chemistry. 280 (46): 38117–20. doi:10.1074/jbc.C500348200. PMID 16150737.
- ^ Creacy SD, Routh ED, Iwamoto F, Nagamine Y, Akman SA, Vaughn JP (December 2008). "G4 resolvase 1 binds both DNA and RNA tetramolecular quadruplex with high affinity and is the major source of tetramolecular quadruplex G4-DNA and G4-RNA resolving activity in HeLa cell lysates". The Journal of Biological Chemistry. 283 (50): 34626–34. doi:10.1074/jbc.M806277200. PMC 2596407. PMID 18842585.
- ^ a b Chalupníková K, Lattmann S, Selak N, Iwamoto F, Fujiki Y, Nagamine Y (December 2008). "Recruitment of the RNA helicase RHAU to stress granules via a unique RNA-binding domain". The Journal of Biological Chemistry. 283 (50): 35186–98. doi:10.1074/jbc.M804857200. PMC 3259895. PMID 18854321.
- ^ Chalupníková, Kateřina (2008). "Characterizing functional domains of the RNA helicase RHAU involved in subcellular localization and RNA interaction" (PDF).[unreliable medical source?]
