Kinase Reaction (kinase + reaction)

Distribution by Scientific Domains

Selected Abstracts

Plk3 inhibits pro-apoptotic activity of p73 through physical interaction and phosphorylation

GENES TO CELLS, Issue 7 2009
Meixiang Sang
Plk3, one of Polo-like kinase family members, is involved in the regulation of cell cycle progression and DNA damage response. In this study, we found that Plk3 inhibits pro-apoptotic activity of p73 through physical interaction and phosphorylation. During cisplatin (CDDP)-mediated apoptosis, Plk3 was transcriptionally induced, whereas its protein level was kept at basal level, suggesting that Plk3 might rapidly degrade in response to CDDP. Immunoprecipitation and in vitro pull-down experiments demonstrated that Plk3 interacts with p73. Luciferase reporter assays and RT-PCR experiments revealed that Plk3 inhibits p73-mediated transcriptional activity. Consistent with these results, pro-apoptotic activity of p73 was blocked by Plk3. Additionally, Plk3 decreased the stability of p73. Intriguingly, kinase-deficient Plk3 failed to inhibit p73 function, indicating that kinase activity of Plk3 is required for Plk3-mediated inhibition of p73. Indeed, in vitro kinase reaction showed that NH2 -terminal portion of p73 is phosphorylated by Plk3. In accordance with these observations, knocking down of Plk3 increased the stability of p73 and promoted CDDP-mediated apoptosis in association with up-regulation of p73. Collectively, our present findings suggest that Plk3 plays an important role in the regulation of cell fate determination in response to DNA damage through the inhibition of p73. [source]

Structural insight into nucleotide recognition by human death-associated protein kinase

Laurie K. McNamara
Death-associated protein kinase (DAPK) is a member of the Ca2+/calmodulin-regulated family of serine/threonine protein kinases. The role of the kinase activity of DAPK in eukaryotic cell apoptosis and the ability of bioavailable DAPK inhibitors to rescue neuronal death after brain injury have made it a drug-discovery target for neurodegenerative disorders. In order to understand the recognition of nucleotides by DAPK and to gain insight into DAPK catalysis, the crystal structure of human DAPK was solved in complex with ADP and Mg2+ at 1.85, resolution. ADP is a product of the kinase reaction and product release is considered to be the rate-limiting step of protein kinase catalytic cycles. The structure of DAPK,ADP,Mg2+ was compared with a newly determined DAPK,AMP-PNP,Mg2+ structure and the previously determined apo DAPK structure (PDB code 1jks). The comparison shows that nucleotide-induced changes are localized to the glycine-rich loop region of DAPK. [source]

Ca2+ -activated myosin-ATPases, creatine and adenylate kinases regulate mitochondrial function according to myofibre type in rabbit

N. Gueguen
Mitochondrial respiration rates and their regulation by ADP, AMP and creatine, were studied at different free Ca2+ concentrations (0.1 versus 0.4 ,m) on permeabilized fibre bundles of rabbit skeletal muscles differing in their myosin heavy chain profiles. Four fibre bundle types were obtained: pure types I and IIx, and mixed types IIax (approximately 50% IIa and 50% IIx fibres) and IIb+ (60% IIb fibres, plus IIx and IIa). At rest, pure type I fibres displayed a much higher apparent Km for ADP (212 ,m) than IIx fibres (8 ,m). Within the IIax and IIb+ mixed fibre bundle types, two KADPm values were observed (70 ,m and 5 ,m). Comparison between pure IIx and mixed types indicates that the intermediate Km of 70 ,m most probably corresponds to the mitochondrial affinity for ADP in IIa fibres, the lowest Km for ADP (5 ,m) corresponding to IIx and IIb types. Activation of mitochondrial creatine and adenylate kinase reactions stimulated mitochondrial respiration only in type I and IIax fibre bundles, indicating an efficient coupling between both kinases and ADP rephosphorylation in type I and, likely, IIa fibres, since no effect was observed in pure IIx fibres. Following Ca2+ -induced activation of myosin-ATPase, an increase in mitochondrial sensitivity to ADP of 45% and 250% was observed in type IIax and I bundles, respectively, an effect mostly prevented by addition of vanadate, an inhibitor of myosin-ATPase. Ca2+ -induced activation of myosin-ATPase also prevented the stimulation of respiration rates by creatine and AMP in I and IIax bundles. In addition to differential regulation of mitochondrial respiration and energy transfer systems at rest in I and IIa versus IIx and IIb muscle fibres, our results indicate a regulation of phosphotransfer systems by Ca2+ via the stimulation of myosin-ATPases in type I and IIa fibres of rabbit muscles. [source]

Measurement of Homogeneous Kinase Activity for Cell Lysates Based on the Aggregation of Gold Nanoparticles

CHEMBIOCHEM, Issue 8 2007
Jun Oishi
When the charge sticks. A kinase activity screening system based on the aggregation of gold nanoparticles induced by cationic substrate peptides as coagulants has been constructed. The system can conduct and monitor kinase reactions under homogeneous conditions and has been successfully applied to the kinase assay of cell lysates. [source]