scholarly journals Protein pyrophosphorylation: moving forward

2016 ◽  
Vol 473 (21) ◽  
pp. 3765-3768 ◽  
Author(s):  
Adolfo Saiardi
Keyword(s):  
Membrane Trafficking ◽  
Cell Biology ◽  
Eukaryotic Cell ◽  
Post Translational Modification ◽  
Inositol Pyrophosphate ◽  
Genetic Ablation ◽  
Biochemical Journal ◽  
Inositol Pyrophosphates ◽  
Cellular Motor ◽  
Intermediate Chain

Genetic ablation of inositol pyrophosphate synthesis has established the fundamental importance of this class of molecules to the eukaryote cell. These studies, however, must be complemented by cell biology and biochemical approaches to appreciate the signalling involved in the processes regulated by inositol pyrophosphates. A recent study by Chanduri et al. published in the Biochemical Journal, by integrating multiple experimental approaches, demonstrated that inositol pyrophosphates regulate intracellular vesicular movement. In particular, the vesicular transport along the microtubule that is driven by the motor protein complex dynein. Importantly, one subunit of this cellular motor, dynein 1 intermediate chain 2, undergoes serine pyrophosphorylation, a post-translational modification driven by inositol pyrophosphates. The pyrophosphorylation status of this dynein intermediate chain regulates its interaction with dynactin, which recruits the motor to vesicles. This mechanistically might explain how inositol pyrophosphates control intracellular membrane trafficking. By dissecting the serine pyrophosphorylation process, this work increases our awareness of this modification, underappreciated by the scientific literature but probably not by the eukaryotic cell.

scholarly journals PAK and other Rho-associated kinases – effectors with surprisingly diverse mechanisms of regulation

2005 ◽  
Vol 386 (2) ◽  
pp. 201-214 ◽  
Author(s):  
Zhou-shen ZHAO ◽  
Ed MANSER
Keyword(s):  
Rho Gtpases ◽  
Cell Biology ◽  
Rho Gtpase ◽  
Rho Kinase ◽  
Molecular Switches ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Downstream Effector ◽  
P21 Activated Kinase ◽  
Do So

The Rho GTPases are a family of molecular switches that are critical regulators of signal transduction pathways in eukaryotic cells. They are known principally for their role in regulating the cytoskeleton, and do so by recruiting a variety of downstream effector proteins. Kinases form an important class of Rho effector, and part of the biological complexity brought about by switching on a single GTPase results from downstream phosphorylation cascades. Here we focus on our current understanding of the way in which different Rho-associated serine/threonine kinases, denoted PAK (p21-activated kinase), MLK (mixed-lineage kinase), ROK (Rho-kinase), MRCK (myotonin-related Cdc42-binding kinase), CRIK (citron kinase) and PKN (protein kinase novel), interact with and are regulated by their partner GTPases. All of these kinases have in common an ability to dimerize, and in most cases interact with a variety of other proteins that are important for their function. A diversity of known structures underpin the Rho GTPase–kinase interaction, but only in the case of PAK do we have a good molecular understanding of kinase regulation. The ability of Rho GTPases to co-ordinate spatial and temporal phosphorylation events explains in part their prominent role in eukaryotic cell biology.

scholarly journals Novel Substrates for Kinases Involved in the Biosynthesis of Inositol Pyrophosphates and Their Enhancement of ATPase Activity of a Kinase

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3601
Author(s):  
Raja Mohanrao ◽  
Ruth Manorama ◽  
Shubhra Ganguli ◽  
Mithun C. Madhusudhanan ◽  
Rashna Bhandari ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Catalytic Domain ◽  
Inositol Phosphate ◽  
Substrate Recognition ◽  
Competitive Inhibitor ◽  
Inositol Polyphosphates ◽  
Inositol Pyrophosphate ◽  
Phosphate Donor ◽  
Inositol Pyrophosphates

IP6K and PPIP5K are two kinases involved in the synthesis of inositol pyrophosphates. Synthetic analogs or mimics are necessary to understand the substrate specificity of these enzymes and to find molecules that can alter inositol pyrophosphate synthesis. In this context, we synthesized four scyllo-inositol polyphosphates—scyllo-IP5, scyllo-IP6, scyllo-IP7 and Bz-scyllo-IP5—from myo-inositol and studied their activity as substrates for mouse IP6K1 and the catalytic domain of VIP1, the budding yeast variant of PPIP5K. We incubated these scyllo-inositol polyphosphates with these kinases and ATP as the phosphate donor. We tracked enzyme activity by measuring the amount of radiolabeled scyllo-inositol pyrophosphate product formed and the amount of ATP consumed. All scyllo-inositol polyphosphates are substrates for both the kinases but they are weaker than the corresponding myo-inositol phosphate. Our study reveals the importance of axial-hydroxyl/phosphate for IP6K1 substrate recognition. We found that all these derivatives enhance the ATPase activity of VIP1. We found very weak ligand-induced ATPase activity for IP6K1. Benzoyl-scyllo-IP5 was the most potent ligand to induce IP6K1 ATPase activity despite being a weak substrate. This compound could have potential as a competitive inhibitor.

scholarly journals Mitochondrial DNA: an advance in eukaryotic cell biology in the 1960s

2005 ◽  
Vol 97 (9) ◽  
pp. 743-748 ◽  
Author(s):  
Jean-Claude Mounolou ◽  
François Lacroute
Keyword(s):  
Mitochondrial Dna ◽  
Cell Biology ◽  
Eukaryotic Cell ◽  
The 1960S

scholarly journals Involvement of a novel ADP-ribosylation factor GTPase-activating protein, SMAP, in membrane trafficking: Implications in cancer cell biology

2006 ◽  
Vol 97 (9) ◽  
pp. 801-806 ◽  
Author(s):  
Kenji Tanabe ◽  
Shunsuke Kon ◽  
Waka Natsume ◽  
Tetsuo Torii ◽  
Toshio Watanabe ◽  
...  
Keyword(s):  
Cancer Cell ◽  
Membrane Trafficking ◽  
Cell Biology ◽  
Gtpase Activating Protein ◽  
Adp Ribosylation ◽  
Adp Ribosylation Factor

The sweet side of AMPK signaling: regulation of GFAT1

2017 ◽  
Vol 474 (7) ◽  
pp. 1289-1292 ◽  
Author(s):  
John W. Scott ◽  
Jonathan S. Oakhill
Keyword(s):  
Energy Demand ◽  
Dynamic Control ◽  
Cellular Protein ◽  
Post Translational Modification ◽  
Nutrient Metabolism ◽  
Ampk Signaling ◽  
Biochemical Journal ◽  
Signaling Axis ◽  
Hexosamine Biosynthesis ◽  
Living Organisms

Maintaining a steady balance between nutrient supply and energy demand is essential for all living organisms and is achieved through the dynamic control of metabolic processes that produce and consume adenosine-5′-triphosphate (ATP), the universal currency of energy in all cells. A key sensor of cellular energy is the adenosine-5′-monophosphate (AMP)-activated protein kinase (AMPK), which is the core component of a signaling network that regulates energy and nutrient metabolism. AMPK is activated by metabolic stresses that decrease cellular ATP, and functions to restore energy balance by orchestrating a switch in metabolism away from anabolic pathways toward energy-generating catabolic processes. A new study published in a recent issue of Biochemical Journal by Zibrova et al. shows that glutamine:fructose-6-phosphate amidotransferase-1 (GFAT1), the rate-limiting enzyme of the hexosamine biosynthesis pathway (HBP), is a physiological substrate of AMPK. The HBP is an offshoot of the glycolytic pathway that drives the synthesis of uridine-5′-diphospho-N-acetylglucosamine, the requisite donor metabolite needed for dynamic β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) of cellular proteins. O-GlcNAcylation is a nutrient-sensitive post-translational modification that, like phosphorylation, regulates numerous intracellular processes. Zibrova et al. show that inhibitory phosphorylation of the GFAT1 residue Ser243 by AMPK in response to physiological or small-molecule activators leads to a reduction in cellular protein O-GlcNAcylation. Further work revealed that AMPK-dependent phosphorylation of GFAT1 promotes angiogenesis in endothelial cells. This elegant study demonstrates that the AMPK–GFAT1 signaling axis serves as an important communication point between two nutrient-sensitive signaling pathways and is likely to play a significant role in controlling physiological processes in many other tissues.

scholarly journals Back to the future: new target-validated Rab antibodies for evaluating LRRK2 signalling in cell biology and Parkinson's disease

2018 ◽  
Vol 475 (1) ◽  
pp. 185-189 ◽  
Author(s):  
Patrick A. Eyers
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cell Biology ◽  
Human Neutrophils ◽  
Rab Proteins ◽  
Rab Gtpases ◽  
Biochemical Journal ◽  
The Future ◽  
Brain Extracts ◽  
Sporadic Cases

The addition of phosphate groups to substrates allows protein kinases to regulate a myriad of biological processes, and contextual analysis of protein-bound phosphate is important for understanding how kinases contribute to physiology and disease. Leucine-rich repeat kinase 2 (LRRK2) is a Ser/Thr kinase linked to familial and sporadic cases of Parkinson's disease (PD). Recent work established that multiple Rab GTPases are physiological substrates of LRRK2, with Rab10 in particular emerging as a human substrate whose site-specific phosphorylation mirrors hyperactive LRRK2 lesions associated with PD. However, current assays to quantify Rab10 phosphorylation are expensive, time-consuming and technically challenging. In back-to-back studies reported in the Biochemical Journal, Alessi and colleagues teamed up with clinical colleagues and collaborators at the Michael J. Fox Foundation (MJFF) for Parkinson's research to develop, and validate, a panel of exquisitely sensitive phospho-specific Rab antibodies. Of particular interest, the monoclonal antibody-designated MJFF-pRAB10 detects phosphorylated Rab 10 on Thr73 in a variety of cells, brain extracts, PD-derived samples and human neutrophils, the latter representing a previously unrecognised biological resource for LRRK2 signalling analysis. In the future, these antibodies could become universal resources in the fight to understand and quantify connections between LRRK2 and Rab proteins, including those associated with clinical PD.

scholarly journals Inositol polyphosphates intersect with signaling and metabolic networks via two distinct mechanisms

2016 ◽  
Vol 113 (44) ◽  
pp. E6757-E6765 ◽  
Author(s):  
Mingxuan Wu ◽  
Lucy S. Chong ◽  
David H. Perlman ◽  
Adam C. Resnick ◽  
Dorothea Fiedler
Keyword(s):  
Ribosome Biogenesis ◽  
Metabolic Networks ◽  
Central Line ◽  
Eukaryotic Cell ◽  
Nucleotide Metabolism ◽  
Telomere Maintenance ◽  
Inositol Polyphosphates ◽  
Protein Targets ◽  
Messenger Molecules ◽  
Inositol Pyrophosphates

Inositol-based signaling molecules are central eukaryotic messengers and include the highly phosphorylated, diffusible inositol polyphosphates (InsPs) and inositol pyrophosphates (PP-InsPs). Despite the essential cellular regulatory functions of InsPs and PP-InsPs (including telomere maintenance, phosphate sensing, cell migration, and insulin secretion), the majority of their protein targets remain unknown. Here, the development of InsP and PP-InsP affinity reagents is described to comprehensively annotate the interactome of these messenger molecules. By using the reagents as bait, >150 putative protein targets were discovered from a eukaryotic cell lysate (Saccharomyces cerevisiae). Gene Ontology analysis of the binding partners revealed a significant overrepresentation of proteins involved in nucleotide metabolism, glucose metabolism, ribosome biogenesis, and phosphorylation-based signal transduction pathways. Notably, we isolated and characterized additional substrates of protein pyrophosphorylation, a unique posttranslational modification mediated by the PP-InsPs. Our findings not only demonstrate that the PP-InsPs provide a central line of communication between signaling and metabolic networks, but also highlight the unusual ability of these molecules to access two distinct modes of action.

Sign in / Sign up

Export Citation Format

Share Document