spliceosome RNA helicase DDX39B; 56 kD U2AF65-associated protein; ATP-dependent RNA helicase p47; DEAD box protein UAP56; HLA-B-associated transcript 1 protein (DDX39B BAT1 UAP56)

Function: - component of the THO subcomplex of the TREX complex - splice factor required for the first ATP- dependent step in spliceosome assembly & for the interaction of U2 snRNP with the branchpoint - has both RNA-stimulated ATP binding/hydrolysis activity & ATP-dependent RNA unwinding activity - even with the stimulation of RNA, the ATPase activity is weak - can only hydrolyze ATP but not other NTPs - the RNA stimulation of ATPase activity does not have a strong preference for the sequence & length of the RNA - however, ssRNA stimulates the ATPase activity much more strongly than dsRNA - can unwind 5' or 3' overhangs or blunt end RNA duplexes in vitro - the ATPase & helicase activities are not influenced by U2AF2 & THOC4 - homodimer, & heterodimer with DDX39A - component of the spliceosome - interacts directly with U2AF2 - interacts directly with THOC4 & is necessARy for THOC4 recruitment to spliced mRNA - interacts with RBM8A, RNPS1 & SRRM1 - interacts with FYTTD1/UIF & THOC1 Kinetic parameters: - KM=3.3 uM for ATP - Vmax=0.126 uM/min/mg enzyme with ATP as substrate Structure: - the helicase C-terminal domain mediates interaction with THOC4 - belongs to the DEAD box helicase family, DECD subfamily - contains 1 helicase ATP-binding domain - contains 1 helicase C-terminal domain Compartment: nucleus, nuclear speckle Alternative splicing: named isoforms=2

General

DEAD box ATP-dependent helicase phosphoprotein

Properties

SIZE: entity length = 428 aa MW = 49 kD COMPARTMENT: cell nucleus MOTIF: acetylation site SITE: N-TERMINUS EFFECTOR-BOUND: acetyl Q motif {45-73} helicase NAME: helicase SITE: 76-249 MOTIF: ATP-binding site NAME: ATP-binding site SITE: 89-96 Thr phosphorylation site {T172} DECD box {196-199} Helicase C-terminal {261-422}

Database Correlations

OMIM 142560 UniProt Q13838 PFAM correlations Entrez Gene 7919 Kegg hsa:7919 ENZYME 3.6.4.13

References

UniProt :accession Q13838