1
|
Kim C, Sharma R. Cyclic nucleotide selectivity of protein kinase G isozymes. Protein Sci 2020; 30:316-327. [PMID: 33271627 DOI: 10.1002/pro.4008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/25/2020] [Accepted: 12/01/2020] [Indexed: 11/07/2022]
Abstract
The intrinsic activity of the C-terminal catalytic (C) domain of cyclic guanosine monophosphate (cGMP)-dependent protein kinases (PKG) is inhibited by interactions with the N-terminal regulatory (R) domain. Selective binding of cGMP to cyclic nucleotide binding (CNB) domains within the R-domain disrupts the inhibitory R-C interaction, leading to the release and activation of the C-domain. Affinity measurements of mammalian and plasmodium PKG CNB domains reveal different degrees of cyclic nucleotide affinity and selectivity; the CNB domains adjacent to the C-domain are more cGMP selective and therefore critical for cGMP-dependent activation. Crystal structures of isolated CNB domains in the presence and absence of cyclic nucleotides reveal isozyme-specific contacts that explain cyclic nucleotide selectivity and conformational changes that accompany CNB. Crystal structures of tandem CNB domains identify two types of CNB-mediated dimeric contacts that indicate cGMP-driven reorganization of domain-domain interfaces that include large conformational changes. Here, we review the available structural and functional information of PKG CNB domains that further advance our understanding of cGMP mediated regulation and activation of PKG isozymes.
Collapse
Affiliation(s)
- Choel Kim
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Rajesh Sharma
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
2
|
Gerlits O, Campbell JC, Blakeley MP, Kim C, Kovalevsky A. Neutron Crystallography Detects Differences in Protein Dynamics: Structure of the PKG II Cyclic Nucleotide Binding Domain in Complex with an Activator. Biochemistry 2018. [PMID: 29517905 DOI: 10.1021/acs.biochem.8b00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
As one of the main receptors of a second messenger, cGMP, cGMP-dependent protein kinase (PKG) isoforms I and II regulate distinct physiological processes. The design of isoform-specific activators is thus of great biomedical importance and requires detailed structural information about PKG isoforms bound with activators, including accurate positions of hydrogen atoms and a description of the hydrogen bonding and water architecture. Here, we determined a 2.2 Å room-temperature joint X-ray/neutron (XN) structure of the human PKG II carboxyl cyclic nucleotide binding (CNB-B) domain bound with a potent PKG II activator, 8-pCPT-cGMP. The XN structure directly visualizes intermolecular interactions and reveals changes in hydrogen bonding patterns upon comparison to the X-ray structure determined at cryo-temperatures. Comparative analysis of the backbone hydrogen/deuterium exchange patterns in PKG II:8-pCPT-cGMP and previously reported PKG Iβ:cGMP XN structures suggests that the ability of these agonists to activate PKG is related to how effectively they quench dynamics of the cyclic nucleotide binding pocket and the surrounding regions.
Collapse
Affiliation(s)
- Oksana Gerlits
- Bredesen Center , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - James C Campbell
- Department of Pharmacology and Chemical Biology , Baylor College of Medicine , Houston , Texas 77030 , United States
| | - Matthew P Blakeley
- Large-Scale Structures Group , Institut Laue Langevin , 38042 Grenoble Cedex 9, France
| | - Choel Kim
- Department of Pharmacology and Chemical Biology , Baylor College of Medicine , Houston , Texas 77030 , United States.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology , Baylor College of Medicine , Houston , Texas 77030 , United States
| | - Andrey Kovalevsky
- Neutron Scattering Division, Neutron Sciences Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| |
Collapse
|
3
|
Campbell JC, Kim JJ, Li KY, Huang GY, Reger AS, Matsuda S, Sankaran B, Link TM, Yuasa K, Ladbury JE, Casteel DE, Kim C. Structural Basis of Cyclic Nucleotide Selectivity in cGMP-dependent Protein Kinase II. J Biol Chem 2016; 291:5623-5633. [PMID: 26769964 PMCID: PMC4786703 DOI: 10.1074/jbc.m115.691303] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/13/2016] [Indexed: 02/04/2023] Open
Abstract
Membrane-bound cGMP-dependent protein kinase (PKG) II is a key regulator of bone growth, renin secretion, and memory formation. Despite its crucial physiological roles, little is known about its cyclic nucleotide selectivity mechanism due to a lack of structural information. Here, we find that the C-terminal cyclic nucleotide binding (CNB-B) domain of PKG II binds cGMP with higher affinity and selectivity when compared with its N-terminal CNB (CNB-A) domain. To understand the structural basis of cGMP selectivity, we solved co-crystal structures of the CNB domains with cyclic nucleotides. Our structures combined with mutagenesis demonstrate that the guanine-specific contacts at Asp-412 and Arg-415 of the αC-helix of CNB-B are crucial for cGMP selectivity and activation of PKG II. Structural comparison with the cGMP selective CNB domains of human PKG I and Plasmodium falciparum PKG (PfPKG) shows different contacts with the guanine moiety, revealing a unique cGMP selectivity mechanism for PKG II.
Collapse
Affiliation(s)
- James C Campbell
- From the Structural and Computational Biology and Molecular Biophysics Program
| | - Jeong Joo Kim
- Department of Pharmacology, and; the Department of Biochemistry, University of Kassel, Kassel, Hesse 34132, Germany
| | - Kevin Y Li
- the Department of Biochemistry & Cell Biology, Rice University, Houston, Texas 77005
| | - Gilbert Y Huang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | | | - Shinya Matsuda
- the Department of Biological Science and Technology, the University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - Banumathi Sankaran
- the Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Todd M Link
- the Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
| | - Keizo Yuasa
- the Department of Biological Science and Technology, the University of Tokushima Graduate School, Tokushima 770-8506, Japan
| | - John E Ladbury
- From the Structural and Computational Biology and Molecular Biophysics Program,; the Department of Biochemistry and Molecular Biology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, and
| | - Darren E Casteel
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093
| | - Choel Kim
- From the Structural and Computational Biology and Molecular Biophysics Program,; Department of Pharmacology, and; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030,.
| |
Collapse
|
4
|
Bhattacharya A, Biswas A, Das PK. Identification of a protein kinase A regulatory subunit from Leishmania having importance in metacyclogenesis through induction of autophagy. Mol Microbiol 2012; 83:548-64. [PMID: 22168343 DOI: 10.1111/j.1365-2958.2011.07950.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
cAMP-mediated responses act as modulators of environmental sensing and cellular differentiation of many kinetoplastidae parasites including Leishmania. Although cAMP synthesizing (adenylate cyclase) and degrading (phosphodiesterase) enzymes have been cloned and characterized from Leishmania, no cAMP-binding effector molecule has yet been identified from this parasite. In this study, a regulatory subunit of cAMP-dependent protein kinase (Ldpkar1), homologous to mammalian class I cAMP-dependent protein kinase regulatory subunit, has been identified from L. donovani. Further characterization suggested possible interaction of LdPKAR1 with PKA catalytic subunits and inhibition of PKA activity. This PKA regulatory subunit is expressed in all life cycle stages and its expression attained maximum level in stationary phase promastigotes, which are biochemically similar to the infective metacyclic promastigotes. Starvation condition, the trigger for metacyclogenesis in the parasite, elevates LdPKAR1 expression and under starvation condition promastigotes overexpressing Ldpkar1 attained metacyclic features earlier than normal cells. Furthermore, Ldpkar1 overexpression accelerates autophagy, a starvation-induced cytological event necessary for metacyclogenesis and amastigote formation. Conditional silencing of Ldpkar1 delays the induction of autophagy in the parasite. The study, for the first time, reports the identification of a functional cAMP-binding effector molecule from Leishmania that may modulate important cytological events affecting metacyclogenesis.
Collapse
|
5
|
Hammelmann V, Zong X, Hofmann F, Michalakis S, Biel M. The cGMP-dependent protein kinase II Is an inhibitory modulator of the hyperpolarization-activated HCN2 channel. PLoS One 2011; 6:e17078. [PMID: 21347269 PMCID: PMC3038938 DOI: 10.1371/journal.pone.0017078] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/20/2011] [Indexed: 11/18/2022] Open
Abstract
Opening of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels is facilitated by direct binding of cyclic nucleotides to a cyclic nucleotide-binding domain (CNBD) in the C-terminus. Here, we show for the first time that in the HCN2 channel cGMP can also exert an inhibitory effect on gating via cGMP-dependent protein kinase II (cGKII)-mediated phosphorylation. Using coimmunoprecipitation and immunohistochemistry we demonstrate that cGKII and HCN2 interact and colocalize with each other upon heterologous expression as well as in native mouse brain. We identify the proximal C-terminus of HCN2 as binding region of cGKII and show that cGKII phosphorylates HCN2 at a specific serine residue (S641) in the C-terminal end of the CNBD. The cGKII shifts the voltage-dependence of HCN2 activation to 2–5 mV more negative voltages and, hence, counteracts the stimulatory effect of cGMP on gating. The inhibitory cGMP effect can be either abolished by mutation of the phosphorylation site in HCN2 or by impairing the catalytic domain of cGKII. By contrast, the inhibitory effect is preserved in a HCN2 mutant carrying a CNBD deficient for cGMP binding. Our data suggest that bidirectional regulation of HCN2 gating by cGMP contributes to cellular fine-tuning of HCN channel activity.
Collapse
Affiliation(s)
- Verena Hammelmann
- Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Xiangang Zong
- Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Franz Hofmann
- Forschergruppe 923 Carvas, Technische Universität München, München, Germany
| | - Stylianos Michalakis
- Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
| | - Martin Biel
- Munich Center for Integrated Protein Science CIPSM and Department of Pharmacy – Center for Drug Research, Ludwig-Maximilians-Universität München, München, Germany
- * E-mail:
| |
Collapse
|
6
|
Leboulle G, Müller U. Synergistic activation of insect cAMP-dependent protein kinase A (type II) by cyclicAMP and cyclicGMP. FEBS Lett 2004; 576:216-20. [PMID: 15474040 DOI: 10.1016/j.febslet.2004.08.079] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2004] [Revised: 08/06/2004] [Accepted: 08/17/2004] [Indexed: 11/19/2022]
Abstract
The high cGMP sensitivity of cAMP-dependent protein kinase A (type II) (PKAII) from invertebrates led to the hypothesis that cGMP directly activates PKAII under physiological conditions. We tested this idea using PKAII holoenzyme purified from the honeybee brain in an assay with short stimulation times. In the presence of very low cAMP concentrations, we found a synergistic increase in PKAII activation by physiological cGMP concentrations. Cloning honeybee regulatory subunit RII and phylogenetic comparison of the two cyclic nucleotide-binding sites of RII reveal a high relation of domain A of insect RII with cGMP-binding domains of cGMP-dependent protein kinases.
Collapse
Affiliation(s)
- Gérard Leboulle
- Institut für Biologie, Freie Universität Berlin, Neurobiologie Königin-Luise-Strasse 28/30, D-14195 Berlin, Germany.
| | | |
Collapse
|
7
|
Deng W, Parbhu-Patel A, Meyer DJ, Baker DA. The role of two novel regulatory sites in the activation of the cGMP-dependent protein kinase from Plasmodium falciparum. Biochem J 2003; 374:559-65. [PMID: 12817987 PMCID: PMC1223622 DOI: 10.1042/bj20030474] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Revised: 06/13/2003] [Accepted: 06/20/2003] [Indexed: 11/17/2022]
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) uniquely contains three cGMP binding sites, but also has a 'degenerate' fourth site. The role of each cGMP-binding site in PfPKG activation remains unknown. We have analysed the effect of mutation of each cGMP-binding site (individually and in combination) on PfPKG activation in vitro. The most striking result was that mutation of cGMP site 3 resulted in a 10-49-fold increase in the K (a((cGMP))) value and a 45-55% decrease in maximal activity compared with wild-type. Mutations involving only cGMP-binding sites 1 and 2 had less effect on both the K (a((cGMP))) values and the maximal activities. These results suggest that, although all three cGMP-binding sites are involved in PfPKG activation, cGMP-binding site 3 has the greatest influence on activation. A mutation in the fourth, degenerate cGMP-binding site decreased PfPKG maximal activity by 40%, but did not change the K (a((cGMP))) value for the PfPKG mutant, suggesting that this site does not bind cGMP, but is required for full activation of PfPKG. The distinct activation properties of PfPKG from mammalian isoforms may be exploitable in the design of a parasite-specific inhibitor and development of a novel anti-malarial drug.
Collapse
Affiliation(s)
- Wensheng Deng
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | | | | | | |
Collapse
|
8
|
Wall ME, Francis SH, Corbin JD, Grimes K, Richie-Jannetta R, Kotera J, Macdonald BA, Gibson RR, Trewhella J. Mechanisms associated with cGMP binding and activation of cGMP-dependent protein kinase. Proc Natl Acad Sci U S A 2003; 100:2380-5. [PMID: 12591946 PMCID: PMC151349 DOI: 10.1073/pnas.0534892100] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using small-angle x-ray scattering, we have observed the cGMP-induced elongation of an active, cGMP-dependent, monomeric deletion mutant of cGMP-dependent protein kinase (Delta(1-52)PKG-I beta). On saturation with cGMP, the radius of gyration of Delta(1-52)PKG-I beta increases from 29.4 +/- 0.1 A to 40.1 +/- 0.7 A, and the maximum linear dimension increases from 90 A +/- 10% to 130 A +/- 10%. The elongation is due to a change in the interaction between structured regulatory (R) and catalytic (C) domains. A model of cGMP binding to Delta(1-52)PKG-I beta indicates that elongation of Delta(1-52)PKG-I beta requires binding of cGMP to the low-affinity binding site of the R domain. A comparison with cAMP-dependent protein kinase suggests that both elongation and activation require cGMP binding to both sites; cGMP binding to the low-affinity site therefore seems to be a necessary, but not sufficient, condition for both elongation and activation of Delta(1-52)PKG-I beta. We also predict that there is little or no cooperativity in cGMP binding to the two sites of Delta(1-52)PKG-I beta under the conditions used here. Results obtained by using the Delta(1-52)PKG-I beta monomer indicate that a previously observed elongation of PKG-I alpha is consistent with a pure change in the interaction between the R domain and the C domain, without alteration of the dimerization interaction. This study has revealed important features of molecular mechanisms in the biochemical network describing PKG-I beta activation by cGMP, yielding new insight into ligand activation of cyclic nucleotide-dependent protein kinases, a class of regulatory proteins that is key to many cellular processes.
Collapse
Affiliation(s)
- Michael E Wall
- Computer and Computational Sciences and Bioscience Divisions, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Taylor MK, Ahmed R, Begley M, Uhler MD. Autoinhibition and isoform-specific dominant negative inhibition of the type II cGMP-dependent protein kinase. J Biol Chem 2002; 277:37242-53. [PMID: 12093798 DOI: 10.1074/jbc.m202060200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the absence of cyclic nucleotides, the cAMP-dependent protein kinase and cGMP-dependent protein kinases (cGKs) suppress phosphotransfer activity at the catalytic cleft by competitive inhibition of substrate binding with a pseudosubstrate sequence within the holoenzyme. The magnitude of inhibition can be diminished by autophosphorylation near this pseudosubstrate sequence. Activation of type I cGK (cGKI) and type II cGK (cGKII) are differentially regulated by their cyclic nucleotide-binding sites. To address the possibility that the distinct activation mechanisms of cGKII and cGKI result from differences in the autophosphorylation of the inhibitory domain, we investigated the effects of autophosphorylation on the kinetics of activation. Unlike the type I cGKs (cGKIalpha and Ibeta), cGKII autophosphorylation did not alter the basal activity, nor the sensitivity of the enzyme to cyclic nucleotide activation. To determine residues responsible for autoinhibition of cGKII, Ala was substituted for basic residues (Lys(122), Arg(118), and Arg(119)) or a hydrophobic residue (Val(125)) within the putative pseudosubstrate domain of cGKII. The integrity of these residues was essential for full cGKII autoinhibition. Furthermore, a cGKII truncation mutant containing this autoinhibitory region demonstrated a nanomolar IC(50) toward a constitutively active form of cGKII. Finally, we present evidence that the dominant negative properties of this truncation mutant are specific to cGKII when compared with cAMP-dependent protein kinase Calpha and cGKIbeta. These findings extend the known differences in the activation mechanisms among cGK isoforms and allow the design of an isoform-specific cGKII inhibitor.
Collapse
Affiliation(s)
- Merritt K Taylor
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48104, USA
| | | | | | | |
Collapse
|
10
|
Gurnett AM, Liberator PA, Dulski PM, Salowe SP, Donald RGK, Anderson JW, Wiltsie J, Diaz CA, Harris G, Chang B, Darkin-Rattray SJ, Nare B, Crumley T, Blum PS, Misura AS, Tamas T, Sardana MK, Yuan J, Biftu T, Schmatz DM. Purification and molecular characterization of cGMP-dependent protein kinase from Apicomplexan parasites. A novel chemotherapeutic target. J Biol Chem 2002; 277:15913-22. [PMID: 11834729 DOI: 10.1074/jbc.m108393200] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The trisubstituted pyrrole 4-[2-(4-fluorophenyl)-5-(1-methylpiperidine-4-yl)-1H-pyrrol-3-yl]pyridine (Compound 1) inhibits the growth of Eimeria spp. both in vitro and in vivo. The molecular target of Compound 1 was identified as cGMP-dependent protein kinase (PKG) using a tritiated analogue to purify a approximately 120-kDa protein from lysates of Eimeria tenella. This represents the first example of a protozoal PKG. Cloning of PKG from several Apicomplexan parasites has identified a parasite signature sequence of nearly 300 amino acids that is not found in mammalian or Drosophila PKG and which contains an additional, third cGMP-binding site. Nucleotide cofactor regulation of parasite PKG is remarkably different from mammalian enzymes. The activity of both native and recombinant E. tenella PKG is stimulated 1000-fold by cGMP, with significant cooperativity. Two isoforms of the parasite enzyme are expressed from a single copy gene. NH(2)-terminal sequence of the soluble isoform of PKG is consistent with alternative translation initiation within the open reading frame of the enzyme. A larger, membrane-associated isoform corresponds to the deduced full-length protein sequence. Compound 1 is a potent inhibitor of both soluble and membrane-associated isoforms of native PKG, as well as recombinant enzyme, with an IC(50) of <1 nm.
Collapse
Affiliation(s)
- Anne M Gurnett
- Department of Human and Animal Infectious Disease Research, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Shalaby T, Liniger M, Seebeck T. The regulatory subunit of a cGMP-regulated protein kinase A of Trypanosoma brucei. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:6197-206. [PMID: 11733015 DOI: 10.1046/j.0014-2956.2001.02564.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study reports the identification and characterization of the regulatory subunit, TbRSU, of protein kinase A of the parasitic protozoon Trypanosoma brucei. TbRSU is coded for by a single copy gene. The protein contains an unusually long N-terminal domain, the pseudosubstrate site involved in binding and inactivation of the catalytic subunit, and two C-terminally located, closely spaced cyclic nucleotide binding domains. Immunoprecipitation of TbRSU coprecipitates a protein kinase activity with the characteristics of protein kinase A: it phosphorylates a protein kinase specific substrate, and it is strongly inhibited by a synthetic protein kinase inhibitor peptide. Unexpectedly, this kinase activity could not be stimulated by cAMP, but by cGMP only. Binding studies with recombinant cyclic nucleotide binding domains of TbRSU confirmed that both domains bind cGMP with Kd values in the lower micromolar range, and that up to a 100-fold excess of cAMP does not compete with cGMP binding.
Collapse
Affiliation(s)
- T Shalaby
- Institute of Cell Biology, University of Bern, Switzerland
| | | | | |
Collapse
|
12
|
Stansberry J, Baude EJ, Taylor MK, Chen PJ, Jin SW, Ellis RE, Uhler MD. A cGMP-dependent protein kinase is implicated in wild-type motility in C. elegans. J Neurochem 2001; 76:1177-87. [PMID: 11181837 DOI: 10.1046/j.1471-4159.2001.00131.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In mammals, cyclic GMP and cGMP-dependent protein kinases (cGKs) have been implicated in the regulation of many neuronal functions including long-term potentiation and long-term depression of synaptic efficacy. To develop Caenorhabditis elegans as a model system for studying the neuronal function of the cGKs, we cloned and characterized the cgk-1 gene. A combination of approaches showed that cgk-1 produces three transcripts, which differ in their first exon but are similar in length. Northern analysis of C. elegans RNA, performed with a probe designed to hybridize to all three transcripts, confirmed that a major 3.0 kb cgk-1 transcript is present at all stages of development. To determine if the CGK-1C protein was a cGMP-dependent protein kinase, CGK-1C was expressed in SF:9 cells and purified. CGK-1C shows a K(a) of 190 +/- 14 nM for cGMP and 18.4 +/- 2 microM for cAMP. Furthermore, CGK-1C undergoes autophosphorylation in a cGMP-dependent manner and is inhibited by the commonly used cGK inhibitor, KT5823. To determine which cells expressed CGK-1C, a 2.4-kb DNA fragment from the promoter of CGK-1C was used to drive GFP expression. The CGK-1C reporter construct is strongly expressed in the ventral nerve cord and in several other neurons as well as the marginal cells of the pharynx and intestine. Finally, RNA-mediated interference of CGK-1 resulted in movement defects in nematode larvae. These results provide the first demonstration that cGMP-dependent protein kinase is present in neurons of C. elegans and show that this kinase is required for normal motility.
Collapse
Affiliation(s)
- J Stansberry
- Department of Biological Chemistry, Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | | | | | | | |
Collapse
|