Biomaterial Database

Interactions between double-stranded RNA regulators and the protein kinase DAI. 1992

L Manche, and S R Green, and C Schmedt, and M B Mathews

Cold Spring Harbor Laboratory, New York 11724.

The interferon-induced protein kinase DAI, the double-stranded RNA (dsRNA)-activated inhibitor of translation, plays a key role in regulating protein synthesis in higher cells. Once activated, in a process that involves autophosphorylation, it phosphorylates the initiation factor eIF-2, leading to inhibition of polypeptide chain initiation. The activity of DAI is controlled by RNA regulators, including dsRNA activators and highly structured single-stranded RNAs which block activation by dsRNA. To elucidate the mechanism of activation, we studied the interaction of DAI with RNA duplexes of discrete sizes. Molecules shorter than 30 bp fail to bind stably and do not activate the enzyme, but at high concentrations they prevent activation by long dsRNA. Molecules longer than 30 bp bind and activate the enzyme, with an efficiency that increases with increasing chain length, reaching a maximum at about 85 bp. These dsRNAs fail to activate at high concentrations and also prevent activation by long dsRNA. Analysis of complexes between dsRNA and DAI suggests that at maximal packing the enzyme interacts with as little as a single helical turn of dsRNA (11 bp) but under conditions that allow activation the binding site protects about 80 bp of duplex. When the RNA-binding site is fully occupied with an RNA activator, the complex appears to undergo a conformational change.

UI	MeSH Term	Description	Entries
D011494	Protein Kinases	A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.	Protein Kinase,Kinase, Protein,Kinases, Protein
D004789	Enzyme Activation	Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.	Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012330	RNA, Double-Stranded	RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. Most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms.	Double-Stranded RNA,Double Stranded RNA,RNA, Double Stranded
D047428	Protein Kinase Inhibitors	Agents that inhibit PROTEIN KINASES.	Protein Kinase Inhibitor,Inhibitor, Protein Kinase,Inhibitors, Protein Kinase,Kinase Inhibitor, Protein,Kinase Inhibitors, Protein
D019892	eIF-2 Kinase	A dsRNA-activated cAMP-independent protein serine/threonine kinase that is induced by interferon. In the presence of dsRNA and ATP, the kinase autophosphorylates on several serine and threonine residues. The phosphorylated enzyme catalyzes the phosphorylation of the alpha subunit of EUKARYOTIC INITIATION FACTOR-2, leading to the inhibition of protein synthesis.	Protein Kinase PKR,Protein Kinase, RNA Activated,RNA-Dependent Protein Kinase,p68 Kinase,DAI Protein Kinase,DSRNA-Dep Protein Kinase,Double Stranded RNA-Dependent Kinase (dsl),Double Stranded RNA-Dependent eIF-2 alpha Protein Kinase,Eukaryotic Initiation Factor 2alpha Kinase,Heme Controlled Repressor,Heme-Controlled Inhibitor,Heme-Controlled Translational Repressor,Heme-Regulated eIF-2alpha Kinase,Hemin Controlled Repressor,Hemin-Controlled Translational Repressor,P68 Protein Kinase,Self-Phosphorylating Protein Kinase,TIK Kinase,dsRNA-Activated Inhibitor,eIF-2alpha Kinase,eRF, eIF-2 Recycling Factor,p65 Kinase,Controlled Repressor, Heme,Controlled Repressor, Hemin,DSRNA Dep Protein Kinase,Double Stranded RNA Dependent eIF 2 alpha Protein Kinase,Heme Controlled Inhibitor,Heme Controlled Translational Repressor,Heme Regulated eIF 2alpha Kinase,Hemin Controlled Translational Repressor,Inhibitor, Heme-Controlled,Inhibitor, dsRNA-Activated,Kinase PKR, Protein,Kinase, DAI Protein,Kinase, DSRNA-Dep Protein,Kinase, Heme-Regulated eIF-2alpha,Kinase, P68 Protein,Kinase, RNA-Dependent Protein,Kinase, Self-Phosphorylating Protein,Kinase, TIK,Kinase, eIF-2,Kinase, eIF-2alpha,Kinase, p65,Kinase, p68,PKR, Protein Kinase,Protein Kinase, DAI,Protein Kinase, DSRNA-Dep,Protein Kinase, P68,Protein Kinase, RNA-Dependent,Protein Kinase, Self-Phosphorylating,RNA Dependent Protein Kinase,Repressor, Heme Controlled,Repressor, Heme-Controlled Translational,Repressor, Hemin Controlled,Repressor, Hemin-Controlled Translational,Self Phosphorylating Protein Kinase,Translational Repressor, Heme-Controlled,Translational Repressor, Hemin-Controlled,dsRNA Activated Inhibitor,eIF 2 Kinase,eIF 2alpha Kinase,eIF-2alpha Kinase, Heme-Regulated,eRF, eIF 2 Recycling Factor