RHAU
Encyclopedia
RHAU is a 114-kDa human RNA helicase
Helicase
Helicases are a class of enzymes vital to all living organisms. They are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separating two annealed nucleic acid strands using energy derived from ATP hydrolysis.-Function:Many cellular processes Helicases are a...

 of the DEAH-box family of helicases encoded by the DHX36 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Structure

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

RHAU exhibits a unique ATP-dependent guanine-quadruplex
G-quadruplex
In molecular biology, G-quadruplexes are nucleic acid sequences that are rich in guanine and are capable of forming a four-stranded structure...

 (G4) resolvase activity and specificity for its substrate in vitro. 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 granule
Stress granule
Stress granules are dense aggregations in the cytosol composed of proteins & RNAs that appear when the cell is under stress. The RNA molecules stored are stalled translation pre-initiation complexes - failed attempts to make protein from mRNA. Stress granules are 100-200 nm in size, not...

s (SGs) upon translational arrest induced by various environmental stresses. A region of the first 105 amino acid was shown to be critical for RNA binding and re-localisation to SGs.

External links

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