Structural insight of human DEAD-box protein rck/p54 into its substrate recognition with conformational changes.

Abstract

Human rck/p54, a product of the gene cloned at the breakpoint of t(11; 14) (q23;q32) chromosomal translocation on 11q23 in B-cell lymphoma, is a member of the DEAD-box RNA helicase family. Here, the crystal structure of Nc-rck/p54, the N-terminal core domain of rck/p54, revealed that the P-loop in motif I formed a closed conformation, which was induced by Asn131, a residue unique to the RCK subfamily. It appears that ATP does not bind to the P-loop. The results of dynamic light scattering revealed to ATP-induced conformational change of rck/p54. It was demonstrated that free rck/p54 is a distended molecule in solution, and that the approach between N-terminal core and C-terminal domains for ATP binding would be essential when unwinding RNA. The results from helicase assay using electron micrograph, ATP hydrolytic and luciferase assay showed that c-myc IRES RNA, whose secondary structure regulates IRES-dependant translation, was unwound by rck/p54 and indicated that it is a good substrate for rck/p54. Over-expression of rck/p54 in HeLa cells caused growth inhibition and cell cycle arrest at G2/M with down-regulation of c-myc expression. These findings altogether suggest that rck/p54 may affect the IRES-dependent translation of c-myc even in the cells.

• Authors: Tsutomu Matsui, Keita Hogetsu, Jiro Usukura, Takao Sato, Takashi Kumasaka, Yukihiro Akao, Nobuo Tanaka
• Journal: Genes to cells : devoted to molecular & cellular mechanisms (Genes Cells) Vol. 11 Issue 4 Pg. 439-52 (Apr 2006) ISSN: 1356-9597 [Print] England
• PMID: 16611246 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Proto-Oncogene Proteins
• Proto-Oncogene Proteins c-myc
• RNA, Messenger
• RNA
• Adenosine Triphosphate
• RNA Nucleotidyltransferases
• DDX6 protein, human
• DEAD-box RNA Helicases

Topics

• Adenosine Triphosphate (chemistry)
• Amino Acid Sequence
• Binding Sites
• Cell Cycle (physiology)
• Cell Division (genetics, physiology)
• Cell Proliferation
• DEAD-box RNA Helicases
• Down-Regulation
• G2 Phase (genetics, physiology)
• Gene Expression Regulation
• HeLa Cells
• Humans
• Molecular Sequence Data
• Protein Conformation
• Protein Structure, Tertiary
• Proto-Oncogene Proteins (chemistry, genetics)
• Proto-Oncogene Proteins c-myc (genetics, metabolism)
• RNA (chemistry)
• RNA Nucleotidyltransferases (chemistry, genetics)
• RNA, Messenger (genetics, metabolism)
• Ribosomes (chemistry)
• Sequence Homology, Amino Acid