101
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de Leng WWJ, Jansen M, Carvalho R, Polak M, Musler AR, Milne ANA, Keller JJ, Menko FH, de Rooij FWM, Iacobuzio-Donahue CA, Giardiello FM, Weterman MAJ, Offerhaus GJA. Genetic defects underlying Peutz-Jeghers syndrome (PJS) and exclusion of the polarity-associated MARK/Par1 gene family as potential PJS candidates. Clin Genet 2007; 72:568-73. [PMID: 17924967 DOI: 10.1111/j.1399-0004.2007.00907.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
LKB1/STK11 germline inactivations are identified in the majority (66-94%) of Peutz-Jeghers syndrome (PJS) patients. Therefore, defects in other genes or so far unidentified ways of LKB1 inactivation may cause PJS. The genes encoding the MARK proteins, homologues of the Par1 polarity protein that associates with Par4/Lkb1, were analyzed in this study because of their link to LKB1 and cell polarity. The genetic defect underlying PJS was determined through analysis of both LKB1 and all four MARK genes. LKB1 point mutations and small deletions were identified in 18 of 23 PJS families using direct sequencing and multiplex ligation-dependent probe amplification analysis identified exon deletions in 3 of 23 families. In total, 91% of the studied families showed LKB1 inactivation. Furthermore, a MARK1, MARK2, MARK3 and MARK4 mutation analysis and an MARK4 quantitative multiplex polymerase chain reaction analysis to identify exon deletions on another eight PJS families without identified LKB1 germline mutation did not identify mutations in the MARK genes. LKB1 defects are the major cause of PJS and genes of the MARK family do not represent alternative PJS genes. Other mechanisms of inactivation of LKB1 may cause PJS in the remaining families.
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Affiliation(s)
- W W J de Leng
- Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands.
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102
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Fang L, Wang Y, Du D, Yang G, Tak Kwok T, Kai Kong S, Chen B, Chen DJ, Chen Z. Cell polarity protein Par3 complexes with DNA-PK via Ku70 and regulates DNA double-strand break repair. Cell Res 2007; 17:100-16. [PMID: 17287830 DOI: 10.1038/sj.cr.7310145] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The partitioning-defective 3 (Par3), a key component in the conserved Par3/Par6/aPKC complex, plays fundamental roles in cell polarity. Herein we report the identification of Ku70 and Ku80 as novel Par3-interacting proteins through an in vitro binding assay followed by liquid chromatography-tandem mass spectrometry. Ku70/Ku80 proteins are two key regulatory subunits of the DNA-dependent protein kinase (DNA-PK), which plays an essential role in repairing double-strand DNA breaks (DSBs). We determined that the nuclear association of Par3 with Ku70/Ku80 was enhanced by gamma-irradiation (IR), a potent DSB inducer. Furthermore, DNA-PKcs, the catalytic subunit of DNA-PK, interacted with the Par3/Ku70/Ku80 complex in response to IR. Par3 over-expression or knockdown was capable of up- or downregulating DNA-PK activity, respectively. Moreover, the Par3 knockdown cells were found to be defective in random plasmid integration, defective in DSB repair following IR, and radiosensitive, phenotypes similar to that of Ku70 knockdown cells. These findings identify Par3 as a novel component of the DNA-PK complex and implicate an unexpected link of cell polarity to DSB repair.
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Affiliation(s)
- Longhou Fang
- Key Laboratory of Proteomics and Laboratory of Molecular Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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103
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Musso GA, Zhang Z, Emili A. Experimental and computational procedures for the assessment of protein complexes on a genome-wide scale. Chem Rev 2007; 107:3585-600. [PMID: 17630806 DOI: 10.1021/cr0682857] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gabriel A Musso
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario, Canada M5S 3E1
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104
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Hopf C, Bantscheff M, Drewes G. Pathway Proteomics and Chemical Proteomics Team Up in Drug Discovery. NEURODEGENER DIS 2007; 4:270-80. [PMID: 17596721 DOI: 10.1159/000101851] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Over the last 5 years, impressive technical advances in mass spectrometry-based analysis of proteins have enabled the parallel analysis of subproteomes and entire proteomes, thus triggering the departure from the traditional single gene-single protein-single target paradigm. Today, immunoaffinity chromatography as well as generic purification methods employing engineered composite affinity tags make streamlined identification of protein complexes as molecular machines possible. In addition, use of stable isotope techniques in protein mass spectrometry allows for the characterization of protein complex composition and posttranslational modifications in an increasingly quantitative fashion. Together, these methodologies allow the elucidation of medically relevant biological pathways, and the study of the interaction of their protein components with therapeutic agents, on a much larger scale. The present review discusses some of the current experimental strategies, with a focus on applications in neurobiology.
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Affiliation(s)
- Carsten Hopf
- Cellzome AG, Department of Discovery Research, Heidelberg, Germany.
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105
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Kothapalli KS, Anthony JC, Pan BS, Hsieh AT, Nathanielsz PW, Brenna JT. Differential cerebral cortex transcriptomes of baboon neonates consuming moderate and high docosahexaenoic acid formulas. PLoS One 2007; 2:e370. [PMID: 17426818 PMCID: PMC1847718 DOI: 10.1371/journal.pone.0000370] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 03/20/2007] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) are the major long chain polyunsaturated fatty acids (LCPUFA) of the central nervous system (CNS). These nutrients are present in most infant formulas at modest levels, intended to support visual and neural development. There are no investigations in primates of the biological consequences of dietary DHA at levels above those present in formulas but within normal breastmilk levels. METHODS AND FINDINGS Twelve baboons were divided into three formula groups: Control, with no DHA-ARA; "L", LCPUFA, with 0.33%DHA-0.67%ARA; "L3", LCPUFA, with 1.00%DHA-0.67%ARA. All the samples are from the precentral gyrus of cerebral cortex brain regions. At 12 weeks of age, changes in gene expression were detected in 1,108 of 54,000 probe sets (2.05%), with most showing <2-fold change. Gene ontology analysis assigns them to diverse biological functions, notably lipid metabolism and transport, G-protein and signal transduction, development, visual perception, cytoskeleton, peptidases, stress response, transcription regulation, and 400 transcripts having no defined function. PLA2G6, a phospholipase recently associated with infantile neuroaxonal dystrophy, was downregulated in both LCPUFA groups. ELOVL5, a PUFA elongase, was the only LCPUFA biosynthetic enzyme that was differentially expressed. Mitochondrial fatty acid carrier, CPT2, was among several genes associated with mitochondrial fatty acid oxidation to be downregulated by high DHA, while the mitochondrial proton carrier, UCP2, was upregulated. TIMM8A, also known as deafness/dystonia peptide 1, was among several differentially expressed neural development genes. LUM and TIMP3, associated with corneal structure and age-related macular degeneration, respectively, were among visual perception genes influenced by LCPUFA. TIA1, a silencer of COX2 gene translation, is upregulated by high DHA. Ingenuity pathway analysis identified a highly significant nervous system network, with epidermal growth factor receptor (EGFR) as the outstanding interaction partner. CONCLUSIONS These data indicate that LCPUFA concentrations within the normal range of human breastmilk induce global changes in gene expression across a wide array of processes, in addition to changes in visual and neural function normally associated with formula LCPUFA.
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Affiliation(s)
- Kumar S.D. Kothapalli
- Division of Nutritional Sciences, Cornell University, Savage Hall, Ithaca, New York, United States of America
| | - Joshua C. Anthony
- Mead Johnson and Company, Evansville, Indiana, United States of America
| | - Bruce S. Pan
- Division of Nutritional Sciences, Cornell University, Savage Hall, Ithaca, New York, United States of America
| | - Andrea T. Hsieh
- Division of Nutritional Sciences, Cornell University, Savage Hall, Ithaca, New York, United States of America
| | - Peter W. Nathanielsz
- Center for Pregnancy and Newborn Research, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - J. Thomas Brenna
- Division of Nutritional Sciences, Cornell University, Savage Hall, Ithaca, New York, United States of America
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106
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Wang JW, Imai Y, Lu B. Activation of PAR-1 kinase and stimulation of tau phosphorylation by diverse signals require the tumor suppressor protein LKB1. J Neurosci 2007; 27:574-81. [PMID: 17234589 PMCID: PMC6672797 DOI: 10.1523/jneurosci.5094-06.2007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aberrant phosphorylation of tau is associated with a number of neurodegenerative diseases, including Alzheimer's disease (AD). The molecular mechanisms by which tau phosphorylation is regulated under normal and disease conditions are not well understood. Microtubule affinity regulating kinase (MARK) and PAR-1 have been identified as physiological tau kinases, and aberrant phosphorylation of MARK/PAR-1 target sites in tau has been observed in AD patients and animal models. Here we show that phosphorylation of PAR-1 by the tumor suppressor protein LKB1 is required for PAR-1 activation, which in turn promotes tau phosphorylation in Drosophila. Diverse stress stimuli, such as high osmolarity and overexpression of the human beta-amyloid precursor protein, can promote PAR-1 activation and tau phosphorylation in an LKB1-dependent manner. These results reveal a new function for the tumor suppressor protein LKB1 in a signaling cascade through which the phosphorylation and function of tau is regulated by diverse signals under physiological and pathological conditions.
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Affiliation(s)
- Ji-Wu Wang
- Department of Pathology, Stanford University School of Medicine, and Geriatric Research, Education, and Clinical Center/Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304
| | - Yuzuru Imai
- Department of Pathology, Stanford University School of Medicine, and Geriatric Research, Education, and Clinical Center/Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, and Geriatric Research, Education, and Clinical Center/Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304
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107
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Abstract
This review focuses on remarkable recent findings concerning the mechanism by which the LKB1 protein kinase that is mutated in Peutz-Jeghers cancer syndrome operates as a tumor suppressor. We discuss evidence that the cellular localization and activity of LKB1 is controlled through its interaction with a catalytically inactive protein resembling a protein kinase, termed STRAD, and an armadillo repeat-containing protein, named mouse protein 25 (MO25). The data suggest that LKB1 functions as a tumor suppressor by not only inhibiting proliferation, but also by exerting profound effects on cell polarity and, most unexpectedly, on the ability of a cell to detect and respond to low cellular energy levels. Genetic and biochemical findings indicate that LKB1 exerts its effects by phosphorylating and activating 14 protein kinases, all related to the AMP-activated protein kinase. The work described in this review shows how a study of an obscure cancer syndrome can uncover new and important regulatory pathways, relevant to the understanding of multiple human diseases.
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Affiliation(s)
- Dario R Alessi
- Medical Research Council, Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland.
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108
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Tsai A, Carstens RP. An optimized protocol for protein purification in cultured mammalian cells using a tandem affinity purification approach. Nat Protoc 2007; 1:2820-7. [PMID: 17406540 DOI: 10.1038/nprot.2006.371] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes a method that we developed to adapt the tandem affinity purification (TAP) approach for use in mammalian cells. The protocol involves fusing a protein of interest with a tandem tag consisting of two FLAG tags (FF) followed by two protein-A immunoglobulin G (IgG) binding domains (ZZ). The protocol improves upon previously published TAP approaches by employing FLAG in place of calmodulin binding peptide (CBP) with resulting higher recovery during purification. In addition, we use a bicistronic expression system that ensures recovery of stably transfected cell lines expressing easily detectable levels of the protein of interest. A method is also presented for generating cytoplasmic and nuclear extracts, which extends use of this protocol to identify protein-protein interactions occurring specifically in the cytoplasm or nucleus. This protocol facilitates the preparation of partially purified recombinant protein and identification of protein-protein interactions in mammalian cell culture models. The protocol can be completed in 34 h.
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Affiliation(s)
- Arthur Tsai
- Renal-Electrolyte and Hypertension Division, Department of Medicine, University of Pennsylvania, 415 Curie Boulevard, 700 Clinical Research Building, Philadelphia, PA 19104, USA
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109
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McKinsey TA. Derepression of pathological cardiac genes by members of the CaM kinase superfamily. Cardiovasc Res 2006; 73:667-77. [PMID: 17217938 DOI: 10.1016/j.cardiores.2006.11.036] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 11/22/2006] [Accepted: 11/30/2006] [Indexed: 01/09/2023] Open
Abstract
In response to pathologic stresses such as hypertension or myocardial infarction, the heart undergoes a remodeling process that is characterized by myocyte hypertrophy, myocyte death and fibrosis, resulting in impaired cardiac function and heart failure. Cardiac remodeling is associated with derepression of genes that contribute to disease progression. This review focuses on evidence linking members of the Ca(2+)/calmodulin-dependent protein kinase (CaMK) superfamily, specifically CaMKII, protein kinase D (PKD) and microtubule associated kinase (MARK), to stress-induced derepression of pathological cardiac gene expression through their effects on class IIa histone deacetylases (HDACs).
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Affiliation(s)
- Timothy A McKinsey
- Myogen, Inc./Gilead Colorado, Inc., 7575 West 103rd Ave., Westminster, Colorado 80021, USA.
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110
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Angrand PO, Segura I, Völkel P, Ghidelli S, Terry R, Brajenovic M, Vintersten K, Klein R, Superti-Furga G, Drewes G, Kuster B, Bouwmeester T, Acker-Palmer A. Transgenic Mouse Proteomics Identifies New 14-3-3-associated Proteins Involved in Cytoskeletal Rearrangements and Cell Signaling. Mol Cell Proteomics 2006; 5:2211-27. [PMID: 16959763 DOI: 10.1074/mcp.m600147-mcp200] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Identification of protein-protein interactions is crucial for unraveling cellular processes and biochemical mechanisms of signal transduction. Here we describe, for the first time, the application of the tandem affinity purification (TAP) and LC-MS method to the characterization of protein complexes from transgenic mice. The TAP strategy developed in transgenic mice allows the emplacement of complexes in their physiological environment in contact with proteins that might only be specifically expressed in certain tissues while simultaneously ensuring the right stoichiometry of the TAP protein versus their binding partners and represents a novelty in proteomics approaches used so far. Mouse lines expressing TAP-tagged 14-3-3zeta protein were generated, and protein interactions were determined. 14-3-3 proteins are general regulators of cell signaling and represent up to 1% of the total brain protein. This study allowed the identification of almost 40 novel 14-3-3zeta-binding proteins. Biochemical and functional characterization of some of these interactions revealed new mechanisms of action of 14-3-3zeta in several signaling pathways, such as glutamate receptor signaling via binding to homer homolog 3 (Homer 3) and in cytoskeletal rearrangements and spine morphogenesis by binding and regulating the activity of the signaling complex formed by G protein-coupled receptor kinase-interactor 1 (GIT1) and p21-activated kinase-interacting exchange factor beta (betaPIX).
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Affiliation(s)
- Pierre-Olivier Angrand
- Cellzome AG and the European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
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111
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Nordhoff E, Lehrach H. Identification and characterization of DNA-binding proteins by mass spectrometry. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2006; 104:111-95. [PMID: 17290821 DOI: 10.1007/10_2006_037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Mass spectrometry is the most sensitive and specific analytical technique available for protein identification and quantification. Over the past 10 years, by the use of mass spectrometric techniques hundreds of previously unknown proteins have been identified as DNA-binding proteins that are involved in the regulation of gene expression, replication, or DNA repair. Beyond this task, the applications of mass spectrometry cover all aspects from sequence and modification analysis to protein structure, dynamics, and interactions. In particular, two new, complementary ionization techniques have made this possible: matrix-assisted laser desorption/ionization and electrospray ionization. Their combination with different mass-over-charge analyzers and ion fragmentation techniques, as well as specific enzymatic or chemical reactions and other analytical techniques, has led to the development of a broad repertoire of mass spectrometric methods that are now available for the identification and detailed characterization of DNA-binding proteins. These techniques, how they work, what their requirements and limitations are, and selected examples that document their performance are described and discussed in this chapter.
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Affiliation(s)
- Eckhard Nordhoff
- Department Lehrach, Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany.
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112
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Nikolaou S, Gasser RB. Extending from PARs in Caenorhabditis elegans to homologues in Haemonchus contortus and other parasitic nematodes. Parasitology 2006; 134:461-82. [PMID: 17107637 DOI: 10.1017/s0031182006001727] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 08/23/2006] [Accepted: 10/02/2006] [Indexed: 11/05/2022]
Abstract
Signal transduction molecules play key roles in the regulation of developmental processes, such as morphogenesis, organogenesis and cell differentiation in all organisms. They are organized into 'pathways' that represent a coordinated network of cell-surface receptors and intracellular molecules, being involved in sensing environmental stimuli and transducing signals to regulate or modulate cellular processes, such as gene expression and cytoskeletal dynamics. A particularly important group of molecules implicated in the regulation of the cytoskeleton for the establishment and maintenance of cell polarity is the PAR proteins (derived from partition defective in asymmetric cell division). The present article reviews salient aspects of PAR proteins involved in the early embryonic development and morphogenesis of the free-living nematode Caenorhabditis elegans and some other organisms, with an emphasis on the molecule PAR-1. Recent advances in the knowledge and understanding of PAR-1 homologues from the economically important parasitic nematode, Haemonchus contortus, of small ruminants is summarized and discussed in the context of exploring avenues for future research in this area for parasitic nematodes.
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Affiliation(s)
- S Nikolaou
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia
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113
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Bürckstümmer T, Bennett KL, Preradovic A, Schütze G, Hantschel O, Superti-Furga G, Bauch A. An efficient tandem affinity purification procedure for interaction proteomics in mammalian cells. Nat Methods 2006; 3:1013-9. [PMID: 17060908 DOI: 10.1038/nmeth968] [Citation(s) in RCA: 298] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Accepted: 09/26/2006] [Indexed: 11/09/2022]
Abstract
Tandem affinity purification (TAP) is a generic two-step affinity purification protocol that enables the isolation of protein complexes under close-to-physiological conditions for subsequent analysis by mass spectrometry. Although TAP was instrumental in elucidating the yeast cellular machinery, in mammalian cells the method suffers from a low overall yield. We designed several dual-affinity tags optimized for use in mammalian cells and compared the efficiency of each tag to the conventional TAP tag. A tag based on protein G and the streptavidin-binding peptide (GS-TAP) resulted in a tenfold increase in protein-complex yield and improved the specificity of the procedure. This allows purification of protein complexes that were hitherto not amenable to TAP and use of less starting material, leading to higher success rates and enabling systematic interaction proteomics projects. Using the well-characterized Ku70-Ku80 protein complex as an example, we identified both core elements as well as new candidate effectors.
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Affiliation(s)
- Tilmann Bürckstümmer
- Research Center for Molecular Medicine (CeMM), Lazarettgasse 19/3, 1090 Vienna, Austria
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114
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Morandell S, Stasyk T, Grosstessner-Hain K, Roitinger E, Mechtler K, Bonn GK, Huber LA. Phosphoproteomics strategies for the functional analysis of signal transduction. Proteomics 2006; 6:4047-56. [PMID: 16791829 DOI: 10.1002/pmic.200600058] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Protein phosphorylation is a key regulatory mechanism of cellular signalling processes. The analysis of phosphorylated proteins and the characterisation of phosphorylation sites under different biological conditions are some of the most challenging tasks in current proteomics research. Reduction of the sample complexity is one major step for the analysis of low-abundance kinase substrates, which can be achieved by various subcellular fractionation techniques. One strategy is the enrichment of phosphorylated proteins or peptides by immunoprecipitation or chromatography, e.g. immobilised metal affinity chromatography, prior to analysis. 2-DE gels are powerful tools for the analysis of phosphoproteins when combined with new multiplexing techniques like DIGE, phosphospecific stains, autoradiography or immunoblotting. In addition, several gel-free methods combining chromatography with highly sensitive MS have been successfully applied for the analysis of complex phosphoproteomes. Recently developed approaches like KESTREL or 'chemical genetics' and also protein microarrays offer new possibilities for the identification of specific kinase targets. This review summarises various strategies for the analyses of phosphoproteins with a special focus on the identification of novel kinase substrates.
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Affiliation(s)
- Sandra Morandell
- Division Cell Biology, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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115
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Göransson O, Deak M, Wullschleger S, Morrice NA, Prescott AR, Alessi DR. Regulation of the polarity kinases PAR-1/MARK by 14-3-3 interaction and phosphorylation. J Cell Sci 2006; 119:4059-70. [PMID: 16968750 DOI: 10.1242/jcs.03097] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the PAR-1/MARK kinase family play critical roles in polarity and cell cycle control and are regulated by 14-3-3 scaffolding proteins, as well as the LKB1 tumour suppressor kinase and atypical protein kinase C (PKC). In this study, we initially investigated the mechanism underlying the interaction of mammalian MARK3 with 14-3-3. We demonstrate that 14-3-3 binding to MARK3 is dependent on phosphorylation, and necessitates the phosphate-binding pocket of 14-3-3. We found that interaction with 14-3-3 was not mediated by the previously characterised MARK3 phosphorylation sites, which led us to identify 15 novel sites of phosphorylation. Single point mutation of these sites, as well as the previously identified LKB1-(T211) and the atypical PKC sites (T564/S619), did not disrupt 14-3-3 binding. However, a mutant in which all 17 phosphorylation sites had been converted to alanine residues (termed 17A-MARK3), was no longer able to bind 14-3-3. Wild-type MARK3 was present in both the cytoplasm and plasma membrane, whereas the 17A-MARK3 mutant was strikingly localised at the plasma membrane. We provide data indicating that the membrane localisation of MARK3 required a highly conserved C-terminal domain, which has been termed kinase-associated domain-1 (KA-1). We also show that dissociation of 14-3-3 from MARK3 did not affect catalytic activity, and that a MARK3 mutant, which could not interact with 14-3-3, was normally active. Finally, we establish that there are significant differences in the subcellular localisation of MARK isoforms, as well as in the impact that atypical PKC overexpression has on 14-3-3 binding and localisation. Collectively, these results indicate that 14-3-3 binding to MARK isoforms is mediated by multiple phosphorylation sites, and serves to anchor MARK isoforms in the cytoplasm.
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Affiliation(s)
- Olga Göransson
- University of Dundee, MRC Protein Phosphorylation Unit, James Black Centre, Dow Street, Dundee, DD1 5EH, Scotland, UK.
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116
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Marx A, Nugoor C, Müller J, Panneerselvam S, Timm T, Bilang M, Mylonas E, Svergun DI, Mandelkow EM, Mandelkow E. Structural Variations in the Catalytic and Ubiquitin-associated Domains of Microtubule-associated Protein/Microtubule Affinity Regulating Kinase (MARK) 1 and MARK2. J Biol Chem 2006; 281:27586-99. [PMID: 16803889 DOI: 10.1074/jbc.m604865200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The microtubule-associated protein (MAP)/microtubule affinity regulating kinase (MARK)/Par-1 phosphorylates microtubule-associated proteins tau, MAP2, and MAP4 and is involved in the regulation of microtubule-based transport. Par-1, a homologue of MARK in Drosophila and Caenorhabditis elegans, is essential for the development of embryonic polarity. Four isoforms of MARK are found in humans. Recently, we reported the crystal structure of the catalytic and ubiquitin-associated domains of MARK2, an isoform enriched in brain (Panneerselvam, S., Marx, A., Mandelkow, E.-M., and Mandelkow, E. (2006) Structure 14, 173-183). It showed that the ubiquitin-associated domain (UBA) domain has an unusual fold and binds to the N-terminal lobe of the catalytic domain. This is at variance with a previous low resolution structure derived from small angle solution scattering (Jaleel, M., Villa, F., Deak, M., Toth, R., Prescott, A. R., Van Aalten, D. M., and Alessi, D. R. (2006) Biochem. J. 394, 545-555), which predicts binding of the UBA domain to the larger, C-terminal lobe. Here we report the crystal structure of the catalytic and UBA domain of another isoform, MARK1. Although the crystal packing of the two isoforms are unrelated, the overall conformations of the molecules are similar. Notably, the UBA domain has the same unusual conformation as in MARK2, and it binds at the same site. Remarkable differences occur in the catalytic domain at helix C, the catalytic loop, and the activation segment.
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Affiliation(s)
- Alexander Marx
- Max-Planck-Unit for Structural Molecular Biology, Notkestrasse 85, 22607 Hamburg, Germany
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117
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Beers M, Kemphues K. Depletion of the co-chaperone CDC-37 reveals two modes of PAR-6 cortical association in C. elegans embryos. Development 2006; 133:3745-54. [PMID: 16943281 DOI: 10.1242/dev.02544] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PAR proteins play roles in the establishment and maintenance of polarity in many different cell types in metazoans. In C. elegans, polarity established in the one-cell embryo determines the anteroposterior axis of the developing animal and is essential to set the identities of the early blastomeres. PAR-1 and PAR-2 colocalize at the posterior cortex of the embryo. PAR-3, PAR-6 and PKC-3 (aPKC) colocalize at the anterior cortex of the embryo. A process of mutual exclusion maintains the anterior and posterior protein domains. We present results indicating that a homolog of the Hsp90 co-chaperone Cdc37 plays a role in dynamic interactions among the PAR proteins. We show that CDC-37 is required for the establishment phase of embryonic polarity; that CDC-37 reduction allows PAR-3-independent cortical accumulation of PAR-6 and PKC-3; and that CDC-37 is required for the mutual exclusion of the anterior and posterior group PAR proteins. Our results indicate that CDC-37 acts in part by maintaining PKC-3 levels and in part by influencing the activity or levels of other client proteins. Loss of the activities of these client proteins reveals that there are two sites for PAR-6 cortical association, one dependent on CDC-42 and not associated with PAR-3, and the other independent of CDC-42 and co-localizing with PAR-3. We propose that, in wild-type embryos, CDC-37-mediated inhibition of the CDC-42-dependent binding site and PAR-3-mediated release of this inhibition provide a key mechanism for the anterior accumulation of PAR-6.
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Affiliation(s)
- Melissa Beers
- Department of Molecular Biology and Genetics, 101 Biotechnology Building, Cornell University, Ithaca, NY 14853, USA
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118
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von Trotha JW, Campos-Ortega JA, Reugels AM. Apical localization of ASIP/PAR-3:EGFP in zebrafish neuroepithelial cells involves the oligomerization domain CR1, the PDZ domains, and the C-terminal portion of the protein. Dev Dyn 2006; 235:967-77. [PMID: 16493684 DOI: 10.1002/dvdy.20715] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Neurulation in zebrafish (Danio rerio) embryos is characterized by oriented cell divisions and the progressive establishment of cellular polarity. Mitoses in the neural plate and neural tube are planar, but in the neural keel/rod stage, the mitotic spindle rotates by 90 degrees, causing cell divisions to occur perpendicular to the plane of the neuroepithelium. The mechanisms and molecules that establish cellular polarity and cause the stereotypic orientation of the mitotic spindle during neurulation are largely unknown. In Caenorhabditis elegans and Drosophila, the PAR/aPKC complex has been shown to be involved in both establishment of cellular polarity and spindle orientation. Here, we show that the conserved N-terminal oligomerization domain (CR1) and the PDZ domains of ASIP/PAR-3:EGFP are involved in its localization to the apical membrane in zebrafish neuroepithelial cells. We further show that the C-terminal part of ASIP/PAR-3 contributes to proper localization and that the apical localization signals in ASIP/PAR-3 prevent the basolateral localization of a Numb:PAR-3 fusion protein. The parallel orientation of the mitotic spindle in the neural tube, however, is only weakly impaired upon overexpression of various ASIP/PAR-3:EGFP constructs.
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Affiliation(s)
- Jakob W von Trotha
- Institut für Entwicklungsbiologie, Universität zu Köln, 50923 Köln, Germany
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119
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Bauch A, Superti-Furga G. Charting protein complexes, signaling pathways, and networks in the immune system. Immunol Rev 2006; 210:187-207. [PMID: 16623772 DOI: 10.1111/j.0105-2896.2006.00369.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Systematic deciphering of protein-protein interactions has the potential to generate comprehensive and instructive signaling networks and to fuel new therapeutic and diagnostic strategies. Here, we describe how recent advances in high-throughput proteomic technologies, involving biochemical purification methods and mass spectrometry analysis, can be applied systematically to the characterization of protein complexes and the computation of molecular networks. The networks obtained form the basis for further functional analyses, such as knockdown by RNA interference, ultimately leading to the identification of nodes that represent candidate targets for pharmacological exploitation. No individual experimental approach can accurately elucidate all critical modulatory components and biological aspects of a signaling network. Such functionally annotated protein-protein interaction networks, however, represent an ideal platform for the integration of additional datasets. By providing links between molecules, they also provide links to all previous observations associated with these molecules, be they of genetic, pharmacological, or other origin. As exemplified here by the analysis of the tumor necrosis factor (TNF)-alpha/nuclear factor-kappaB (NF-kappaB) signaling pathway, the approach is applicable to any mammalian cellular signaling pathway in the immune system.
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Affiliation(s)
- Angela Bauch
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.
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120
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Yang P, Sampson HM, Krause HM. A modified tandem affinity purification strategy identifies cofactors of the Drosophila nuclear receptor dHNF4. Proteomics 2006; 6:927-35. [PMID: 16400689 DOI: 10.1002/pmic.200500230] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
With the completion of numerous genome projects, new high-throughput methods are required to ascribe gene function and interactions. A method proven successful in yeast for protein interaction studies is tandem affinity purification (TAP) of native protein complexes followed by MS. Here, we show that TAP, using Protein A and CBP tags, is not generally suitable for the purification and identification of proteins from tissues. A head-to-head comparison of tags shows that two others, FLAG and His, provide protein yields from Drosophila tissues that are an order of magnitude higher than Protein A and CBP. FLAG-His purification worked sufficiently well so that two cofactors of the Drosophila nuclear receptor protein dHNF4 could be purified from whole animals. These proteins, Hsc70 and Hsp83, are important chaperones and cofactors of other nuclear receptor proteins. However, this is the first time that they have been shown to interact with a non-steroid binding nuclear receptor. We show that the two proteins increase the ability of dHNF4 to bind DNA in vitro and to function in vivo. The tags and approaches developed here will help facilitate the routine purification of proteins from complex cells, tissues and whole organisms.
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Affiliation(s)
- Ping Yang
- Banting and Best Department of Medical Research, Department of Medical Genetics and Microbiology, University of Toronto, Charles H. Best Institute, Toronto, Ontario, Canada
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121
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Hao Y, Boyd L, Seydoux G. Stabilization of cell polarity by the C. elegans RING protein PAR-2. Dev Cell 2006; 10:199-208. [PMID: 16459299 PMCID: PMC1712613 DOI: 10.1016/j.devcel.2005.12.015] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 11/11/2005] [Accepted: 12/21/2005] [Indexed: 12/25/2022]
Abstract
Asymmetric localization of PAR proteins is a hallmark of polarized cells, but the mechanisms that create PAR asymmetry are not well understood. In the C. elegans zygote, PAR asymmetry is initiated by a transient actomyosin contraction, which sweeps the PAR-3/PAR-6/PKC-3 complex toward the anterior pole of the egg. The RING finger protein PAR-2 accumulates in a complementary pattern in the posterior cortex. Here we present evidence that PAR-2 participates in a feedback loop to stabilize polarity. PAR-2 is a target of the PKC-3 kinase and is excluded from the anterior cortex by PKC-3-dependent phosphorylation. The RING domain of PAR-2 is required to overcome inhibition by PKC-3 and stabilize PAR-2 on the posterior cortex. Cortical PAR-2 in turn prevents PAR-3/PAR-6/PKC-3 from returning to the posterior, in a PAR-1- and PAR-5-dependent manner. Our findings suggest that reciprocal inhibitory interactions among PAR proteins stabilize polarity by reinforcing an initial asymmetry in PKC-3.
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Affiliation(s)
- Yingsong Hao
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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122
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Nikolaou S, Hartman D, Nisbet AJ, Gasser RB. Haemonchus contortus: prokaryotic expression and enzyme activity of recombinant HcSTK, a serine/threonine protein kinase. Exp Parasitol 2006; 113:207-14. [PMID: 16500645 DOI: 10.1016/j.exppara.2006.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2005] [Revised: 01/09/2006] [Accepted: 01/10/2006] [Indexed: 11/19/2022]
Abstract
Members of the PAR-1/MARK serine/threonine protein kinase (STK) subfamily are important regulators of the cytoskeleton, and their characterization can provide insights into a number of critical processes relating to the development and survival of an organism. We previously investigated the mRNA expression for and organization of a gene (hcstk) representing HcSTK, an STK from the parasitic nematode Haemonchus contortus. In the present study, a recombinant form of HcSTK was expressed and characterized. Affinity-purified anti-HcSTK antibodies reacted with native HcSTK in protein homogenates extracted from third-stage larvae (L3) of H. contortus and were also used to immunolocalize the protein around the nuclei of ovarian and intestinal tissues of adult H. contortus. The enzyme activity of the recombinant HcSTK protein was also demonstrated. The findings show that recombinant HcSTK is a functional protein kinase, with activity directed to KXGS motifs, consistent with other members of the PAR-1/MARK STK subfamily.
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Affiliation(s)
- Sia Nikolaou
- Primary Industries Research Victoria (Animal Genetics and Genomics), 475 Mickleham Road, Attwood, Vic. 3049, Australia
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123
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Bose R, Wrana JL. Regulation of Par6 by extracellular signals. Curr Opin Cell Biol 2006; 18:206-12. [PMID: 16490351 DOI: 10.1016/j.ceb.2006.02.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 02/09/2006] [Indexed: 12/28/2022]
Abstract
The critical regulator of polarity, Par6, is a key member of a multi-component polarity complex that controls a variety of cellular processes such as asymmetric cell division, establishment of epithelial apico-basal polarity, and polarized cell migration. Recently, we have come to understand how regulation of the Par6 interactome by extracellular cues such as integrin and transforming growth factor beta signalling regulates cell motility and tight junction dissolution. These studies have begun to elucidate how signalling to the polarity complex might regulate pathological processes such as tumour cell invasion and metastasis.
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Affiliation(s)
- Rohit Bose
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario, Canada
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124
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Le Guezennec X, Brinkman AB, Vermeulen M, Denissov SG, Gazziola C, Lohrum ME, Stunnenberg HG. Targeted discovery tools: proteomics and chromatin immunoprecipitation-on-chip. BJU Int 2006; 96 Suppl 2:16-22. [PMID: 16359434 DOI: 10.1111/j.1464-410x.2005.05942.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Despite the availability of several completely sequenced genomes, we are still, for the most part, ignorant about how genes interact and regulate each other within a given cell type to specify identity, function and cellular memory. A realistic model of cellular regulation based on current knowledge indicates that many interacting networks operate at the epigenetic, transcriptional, translational and post-translational levels, with feedback between the various levels. Protein-protein and protein-DNA interactions help to define which genes may be activated in a particular cell, and determine whether external cues cause activation or repression. New technologies, e.g. proteomics using mass spectrometry, high-density DNA or oligonucleotide microarrays (chips), and chromatin immunoprecipitation (ChIP), provide new and exciting tools for deciphering the pathways and proteins controlling gene expression. Analysis of these pathways offers new insight that aids targeted drug development.
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Affiliation(s)
- Xavier Le Guezennec
- Nijmegen Center for Molecular Life Sciences, Department of Molecular Biology, Radboud University Nijmegen, Geert Grooteplein 30, Nijmegen, the Netherlands
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125
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Panneerselvam S, Marx A, Mandelkow EM, Mandelkow E. Structure of the Catalytic and Ubiquitin-Associated Domains of the Protein Kinase MARK/Par-1. Structure 2006; 14:173-83. [PMID: 16472737 DOI: 10.1016/j.str.2005.09.022] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 09/13/2005] [Accepted: 09/27/2005] [Indexed: 10/25/2022]
Abstract
The Ser/Thr kinase MARK2 phosphorylates tau protein at sites that cause detachment from microtubules in Alzheimer neurofibrillary degeneration. Homologs of MARK2 include Par-1 in C. elegans and Drosophila, which generates embryonic polarity. We report the X-ray structure of the catalytic and ubiquitin-associated domains (UBA) of human MARK2. The activity was altered by mutations in the ATP binding site and/or activation loop. The catalytic domain shows the small and large lobes typical of kinases. The substrate cleft is in an inactive, open conformation in the inactivated and the wild-type structure. The UBA domain is attached via a taut linker to the large lobe of the kinase domain and leans against a hydrophobic patch on the small lobe. The UBA structure is unusual because the orientation of its third helix is inverted, relative to previous structures. Possible implications of the structure for the regulation of kinase activity are discussed.
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126
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Taylor EB, Lamb JD, Hurst RW, Chesser DG, Ellingson WJ, Greenwood LJ, Porter BB, Herway ST, Winder WW. Endurance training increases skeletal muscle LKB1 and PGC-1alpha protein abundance: effects of time and intensity. Am J Physiol Endocrinol Metab 2005; 289:E960-8. [PMID: 16014350 DOI: 10.1152/ajpendo.00237.2005] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent research suggests that LKB1 is the major AMP-activated protein kinase kinase (AMPKK). Peroxisome-proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) is a master coordinator of mitochondrial biogenesis. Previously we reported that skeletal muscle LKB1 protein increases with endurance training. The purpose of this study was to determine whether training-induced increases in skeletal muscle LKB1 and PGC-1alpha protein exhibit a time course and intensity-dependent response similar to that of citrate synthase. Male Sprague-Dawley rats completed endurance- and interval-training protocols. For endurance training, rats trained for 4, 11, 25, or 53 days. Interval-training rats trained identically to endurance-trained rats, except that after 25 days interval training was combined with endurance training. Time course data were collected from endurance-trained red quadriceps (RQ) after each time point. Interval training data were collected from soleus, RQ, and white quadriceps (WQ) muscle after 53 days only. Mouse protein 25 (MO25) and PGC-1alpha protein increased significantly after 4 days. Increased citrate synthase activity, increased LKB1 protein, and decreased AMPKK activity were found after 11 days. Maximal increases occurred after 4 days for hexokinase II, 25 days for MO25, and 53 days for citrate synthase, LKB1, and PGC-1alpha. In WQ, but not RQ or soleus, interval training had an additive effect to endurance training and induced significant increases in all proteins measured. These results demonstrate that LKB1 and PGC-1alpha protein abundances increase with endurance and interval training similarly to citrate synthase. The increase in LKB1 and PGC-1alpha with endurance and interval training may function to maintain the training-induced increases in mitochondrial mass.
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Affiliation(s)
- Eric B Taylor
- Department of Physiology and Developmental Biology, 545 WIDB, Brigham Young University, Provo, UT 84602, USA
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127
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Jeon S, Kim YS, Park J, Bae CD. Microtubule affinity-regulating kinase 1 (MARK1) is activated by electroconvulsive shock in the rat hippocampus. J Neurochem 2005; 95:1608-18. [PMID: 16238695 DOI: 10.1111/j.1471-4159.2005.03505.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electroconvulsive shock (ECS) induces phosphorylation and dephosphorylation of many signaling molecules in the rat brain. While studying phosphorylated proteins in the rat brain after ECS, we observed a 100-kDa protein that cross-reacted with anti-phospho-p70 S6 kinase antibody, which was subsequently purified and identified as microtubule affinity-regulating kinase 1 (MARK1). Purified MARK1 was phosphorylated at the Ser and Thr residues. MARK1 activation and subsequent Tau phosphorylation in the hippocampus after ECS was confirmed by an in-gel kinase assay using tau protein as a substrate. MARK1 was maximally activated between 2 and 5 min after ECS, and Tau phosphorylation at Ser262 was also increased at 2 min and lasted to 1 h after ECS. Taken together, we concluded that ECS activated MARK1 and subsequently phosphorylated Tau at Ser262. Both MARK1 activity and Tau phosphorylation were increased in the rat hippocampus after chronic ECS where axonal remodeling was apparent. In order to investigate the physiologic stimuli which are involved in the activation of MARK1, SH-SY 5Y cells were treated with brain-derived neurotrophic factor or 60 mm KCl. Both stimuli were capable of inducing MARK activation.
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Affiliation(s)
- Songhee Jeon
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Korea
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128
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Sousa AD, Cheney RE. Myosin-X: a molecular motor at the cell's fingertips. Trends Cell Biol 2005; 15:533-9. [PMID: 16140532 DOI: 10.1016/j.tcb.2005.08.006] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 07/12/2005] [Accepted: 08/19/2005] [Indexed: 10/25/2022]
Abstract
Research in several areas, including unconventional myosins and deafness genes, has converged recently on a group of myosins whose tails contain myosin tail homology 4 (MyTH4) and band 4.1, ezrin, radixin, moesin (FERM) domains. Although these 'MyTH-FERM' myosins are not present in yeast and plants, they are present in slime molds, worms, flies and mammals, where they mediate interactions between the cytoskeleton and the plasma membrane. The most broadly distributed MyTH-FERM myosin in vertebrate cells appears to be myosin-X (Myo10). This myosin can act as a link to integrins and microtubules, stimulate the formation of filopodia and undergo a novel form of motility within filopodia.
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Affiliation(s)
- Aurea D Sousa
- Medical Biomolecular Research Building, Department of Cell and Molecular Physiology, CB #7545, University of North Carolina at Chapel Hill, 27599-7545, USA
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129
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Cusick ME, Klitgord N, Vidal M, Hill DE. Interactome: gateway into systems biology. Hum Mol Genet 2005; 14 Spec No. 2:R171-81. [PMID: 16162640 DOI: 10.1093/hmg/ddi335] [Citation(s) in RCA: 263] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Protein-protein interactions are fundamental to all biological processes, and a comprehensive determination of all protein-protein interactions that can take place in an organism provides a framework for understanding biology as an integrated system. The availability of genome-scale sets of cloned open reading frames has facilitated systematic efforts at creating proteome-scale data sets of protein-protein interactions, which are represented as complex networks or 'interactome' maps. Protein-protein interaction mapping projects that follow stringent criteria, coupled with experimental validation in orthogonal systems, provide high-confidence data sets immanently useful for interrogating developmental and disease mechanisms at a system level as well as elucidating individual protein function and interactome network topology. Although far from complete, currently available maps provide insight into how biochemical properties of proteins and protein complexes are integrated into biological systems. Such maps are also a useful resource to predict the function(s) of thousands of genes.
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Affiliation(s)
- Michael E Cusick
- Center for Cancer Systems Biology and Department of Cancer Biology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA.
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130
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Gunsalus KC, Ge H, Schetter AJ, Goldberg DS, Han JDJ, Hao T, Berriz GF, Bertin N, Huang J, Chuang LS, Li N, Mani R, Hyman AA, Sönnichsen B, Echeverri CJ, Roth FP, Vidal M, Piano F. Predictive models of molecular machines involved in Caenorhabditis elegans early embryogenesis. Nature 2005; 436:861-5. [PMID: 16094371 DOI: 10.1038/nature03876] [Citation(s) in RCA: 221] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Accepted: 05/23/2005] [Indexed: 01/31/2023]
Abstract
Although numerous fundamental aspects of development have been uncovered through the study of individual genes and proteins, system-level models are still missing for most developmental processes. The first two cell divisions of Caenorhabditis elegans embryogenesis constitute an ideal test bed for a system-level approach. Early embryogenesis, including processes such as cell division and establishment of cellular polarity, is readily amenable to large-scale functional analysis. A first step toward a system-level understanding is to provide 'first-draft' models both of the molecular assemblies involved and of the functional connections between them. Here we show that such models can be derived from an integrated gene/protein network generated from three different types of functional relationship: protein interaction, expression profiling similarity and phenotypic profiling similarity, as estimated from detailed early embryonic RNA interference phenotypes systematically recorded for hundreds of early embryogenesis genes. The topology of the integrated network suggests that C. elegans early embryogenesis is achieved through coordination of a limited set of molecular machines. We assessed the overall predictive value of such molecular machine models by dynamic localization of ten previously uncharacterized proteins within the living embryo.
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Affiliation(s)
- Kristin C Gunsalus
- Center for Comparative Functional Genomics, Department of Biology, New York University, New York, New York 10003, USA
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131
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Matenia D, Griesshaber B, Li XY, Thiessen A, Johne C, Jiao J, Mandelkow E, Mandelkow EM. PAK5 kinase is an inhibitor of MARK/Par-1, which leads to stable microtubules and dynamic actin. Mol Biol Cell 2005; 16:4410-22. [PMID: 16014608 PMCID: PMC1196348 DOI: 10.1091/mbc.e05-01-0081] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
MARK/Par-1 is a kinase involved in development of embryonic polarity. In neurons, MARK phosphorylates tau protein and causes its detachment from microtubules, the tracks of axonal transport. Because the target sites of MARK on tau occur at an early stage of Alzheimer neurodegeneration, we searched for interaction partners of MARK. Here we report that MARK2 is negatively regulated by PAK5, a neuronal member of the p21-activated kinase family. PAK5 suppresses the activity of MARK2 toward its target, tau protein. The inhibition requires the binding between the PAK5 and MARK2 catalytic domains, but does not require phosphorylation. In transfected Chinese hamster ovary (CHO) cells both kinases show a vesicular distribution with partial colocalization on endosomes containing AP-1/2. Although MARK2 transfected alone destabilizes microtubules and stabilizes actin stress fibers, PAK5 keeps microtubules stable through the down-regulation of MARK2 but destabilizes the F-actin network so that stress fibers and focal adhesions disappear and cells develop filopodia. The results point to an inverse relationship between actin- and microtubule-related signaling by the PAK5 and MARK2 pathways that affect both cytoskeletal networks.
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Affiliation(s)
- Dorthe Matenia
- Max-Planck-Unit for Structural Molecular Biology, 22607 Hamburg, Germany
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132
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133
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Alhopuro P, Katajisto P, Lehtonen R, Ylisaukko-oja SK, Näätsaari L, Karhu A, Westerman AM, Wilson JHP, de Rooij FWM, Vogel T, Moeslein G, Tomlinson IP, Aaltonen LA, Mäkelä TP, Launonen V. Mutation analysis of three genes encoding novel LKB1-interacting proteins, BRG1, STRADalpha, and MO25alpha, in Peutz-Jeghers syndrome. Br J Cancer 2005; 92:1126-9. [PMID: 15756273 PMCID: PMC2361955 DOI: 10.1038/sj.bjc.6602454] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mutations in LKB1 lead to Peutz–Jeghers syndrome (PJS). However, only a subset of PJS patients harbours LKB1 mutations. We performed a mutation analysis of three genes encoding novel LKB1-interacting proteins, BRG1, STRADα, and MO25α, in 28 LKB1-negative PJS patients. No disease-causing mutations were detected in the studied genes in PJS patients from different European populations.
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Affiliation(s)
- P Alhopuro
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - P Katajisto
- Molecular Cancer Biology Program, Institute of Biomedicine and Helsinki University Central Hospital, Biomedicum Helsinki, Helsinki, Finland
| | - R Lehtonen
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - S K Ylisaukko-oja
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - L Näätsaari
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - A Karhu
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - A M Westerman
- Laboratory of Vascular and Metabolic Diseases, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - J H P Wilson
- Laboratory of Vascular and Metabolic Diseases, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - F W M de Rooij
- Laboratory of Vascular and Metabolic Diseases, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - T Vogel
- Unfallchirurgie, Universitätsklinikum, Heinrich Heine Universität, Düsseldorf, Germany
| | - G Moeslein
- Allgemein- und Viszeralchirurgie, Universitätsklinikum, Heinrich Heine Universität, Düsseldorf, Germany
| | - I P Tomlinson
- Molecular and Population Genetics Laboratory, Imperial Cancer Research Fund, 44, Lincoln's Inn Fields, London WC2A 3PX, UK
| | - L A Aaltonen
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
| | - T P Mäkelä
- Molecular Cancer Biology Program, Institute of Biomedicine and Helsinki University Central Hospital, Biomedicum Helsinki, Helsinki, Finland
| | - V Launonen
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland
- Department of Medical Genetics, Biomedicum Helsinki (Haartmaninkatu 8), University of Helsinki, Helsinki FIN-00014, Finland. E-mail:
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134
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Uetz P, Finley RL. From protein networks to biological systems. FEBS Lett 2005; 579:1821-7. [PMID: 15763558 DOI: 10.1016/j.febslet.2005.02.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2005] [Accepted: 01/31/2005] [Indexed: 11/21/2022]
Abstract
A system-level understanding of any biological process requires a map of the relationships among the various molecules involved. Technologies to detect and predict protein interactions have begun to produce very large maps of protein interactions, some including most of an organism's proteins. These maps can be used to study how proteins work together to form molecular machines and regulatory pathways. They also provide a framework for constructing predictive models of how information and energy flow through biological networks. In many respects, protein interaction maps are an entrée into systems biology.
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Affiliation(s)
- Peter Uetz
- Research Center Karlsruhe, Institute of Genetics, P.O. Box 3640, D-76021 Karlsruhe, Germany.
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135
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Gingras AC, Aebersold R, Raught B. Advances in protein complex analysis using mass spectrometry. J Physiol 2005; 563:11-21. [PMID: 15611014 PMCID: PMC1665575 DOI: 10.1113/jphysiol.2004.080440] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 12/15/2004] [Indexed: 12/28/2022] Open
Abstract
Proteins often function as components of larger complexes to perform a specific function, and formation of these complexes may be regulated. For example, intracellular signalling events often require transient and/or regulated protein-protein interactions for propagation, and protein binding to a specific DNA sequence, RNA molecule or metabolite is often regulated to modulate a particular cellular function. Thus, characterizing protein complexes can offer important insights into protein function. This review describes recent important advances in mass spectrometry (MS)-based techniques for the analysis of protein complexes. Following brief descriptions of how proteins are identified using MS, and general protein complex purification approaches, we address two of the most important issues in these types of studies: specificity and background protein contaminants. Two basic strategies for increasing specificity and decreasing background are presented: whereas (1) tandem affinity purification (TAP) of tagged proteins of interest can dramatically improve the signal-to-noise ratio via the generation of cleaner samples, (2) stable isotopic labelling of proteins may be used to discriminate between contaminants and bona fide binding partners using quantitative MS techniques. Examples, as well as advantages and disadvantages of each approach, are presented.
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136
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Abstract
The study of the epithelium of the adult mammalian intestine touches upon many modern aspects of biology. The epithelium is in a constant dialogue with the underlying mesenchyme to control stem cell activity, proliferation in transit-amplifying compartments, lineage commitment, terminal differentiation and, ultimately, cell death. There are spatially distinct compartments dedicated to each of these events. The Wnt, TGF-beta, BMP, Notch, and Par polarity pathways are the major players in homeostatic control of the adult epithelium. Several hereditary cancer syndromes deregulate these same signaling cascades through mutational (in)activation. Moreover, these mutations often also occur in sporadic tumors. Thus symmetry exists between the roles that these signaling pathways play in physiology and in cancer of the intestine. This is particularly evident for the Wnt/APC pathway, for which the mammalian intestine has become one of the most-studied paradigms. Here, we integrate recent knowledge of the molecular inner workings of the prototype signaling cascades with their specific roles in intestinal epithelial homeostasis and in neoplastic transformation of the epithelium.
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Affiliation(s)
- Elena Sancho
- Institut de Recerca Biomedica de Barcelona (IRBB-PCB) , Parc Cientific de Barcelona, 08028 Barcelona, Spain.
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137
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Abstract
Mutations in the lkb1 gene are found in Peutz-Jeghers syndrome (PJS), with loss of heterozygosity or somatic mutations at the lkb1 locus, suggesting the gene product, the serine/threonine kinase LKB1, may function as a tumour suppressor. Patients with PJS are at a greater risk of developing cancers of epithelial tissue origin. It is widely accepted that the presence of hamartomatous polyps in PJS does not in itself lead to the development of malignancy. The signalling mechanisms that lead to these PJS related malignancies are not well understood. However, it is evident from the recent literature that LKB1 is a multitasking kinase, with unlimited potential in orchestrating cell activity. Thus far, LKB1 has been found to play a role in chromatin remodelling, cell cycle arrest, Wnt signalling, cell polarity, and energy metabolism, all of which may require the tumour suppressor function of this kinase and/or its catalytic activity.
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Affiliation(s)
- P A Marignani
- Dallhousie University, Faculty of Medicine, Department of Biochemistry and Molecular Biology, Halifax, Nova Scotia, Canada.
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138
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Baas AF, Smit L, Clevers H. LKB1 tumor suppressor protein: PARtaker in cell polarity. Trends Cell Biol 2004; 14:312-9. [PMID: 15183188 DOI: 10.1016/j.tcb.2004.04.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The LKB1 (also called serine/threonine kinase 11) tumor suppressor gene was cloned in 1998 by linkage analysis of Peutz-Jeghers cancer syndrome patients. Mammalian LKB1 has been implicated as a regulator of multiple biological processes and signaling pathways, including the control of cell-cycle arrest, p53-mediated apoptosis, Wnt signaling, transforming growth factor (TGF)-beta signaling, ras-induced cell transformation, and energy metabolism. The Caenorhabditis elegans and Drosophila melanogaster LKB1 homologs, termed PAR4 and dLKB1, respectively, regulate cell polarity. Recently, mammalian LKB1 was found to be active only in a complex with two other proteins--STRAD and MO25--and to induce complete polarization of intestinal epithelial cells in a cell-autonomous fashion. In this article, we summarize the findings regarding LKB1 over the past six years. In addition, we discuss LKB1 in polarity in the context of both the other PAR proteins and its tumor suppressive activities.
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Affiliation(s)
- Annette F Baas
- Hubrecht Laboratory, Center for Biomedical Genetics, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
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139
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Taylor EB, Hurst D, Greenwood LJ, Lamb JD, Cline TD, Sudweeks SN, Winder WW. Endurance training increases LKB1 and MO25 protein but not AMP-activated protein kinase kinase activity in skeletal muscle. Am J Physiol Endocrinol Metab 2004; 287:E1082-9. [PMID: 15292028 DOI: 10.1152/ajpendo.00179.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
LKB1 complexed with MO25 and STRAD has been identified as an AMP-activated protein kinase kinase (AMPKK). We measured relative LKB1 protein abundance and AMPKK activity in liver (LV), heart (HT), soleus (SO), red quadriceps (RQ), and white quadriceps (WQ) from sedentary and endurance-trained rats. We examined trained RQ for altered levels of MO25 protein and LKB1, STRAD, and MO25 mRNA. LKB1 protein levels normalized to HT (1 +/- 0.03) were LV (0.50 +/- 0.03), SO (0.28 +/- 0.02), RQ (0.32 +/- 0.01), and WQ (0.12 +/- 0.03). AMPKK activities in nanomoles per gram per minute were HT (79 +/- 6), LV (220 +/- 9), SO (22 +/- 2), RQ (29 +/- 2), and WQ (42 +/- 4). Training increased LKB1 protein in SO, RQ, and WQ (P < 0.05). LKB1 protein levels after training (%controls) were SO (158 +/- 17), RQ (316 +/- 17), WQ (191 +/- 27), HT (106 +/- 2), and LV (104 +/- 7). MO25 protein after training (%controls) was 595 +/- 71. Training did not affect AMPKK activity. MO25 but not LKB1 or STRAD mRNA increased with training (P < 0.05). Trained values (%controls) were MO25 (164 +/- 22), LKB1 (120 +/- 16), and STRAD (112 +/- 17). LKB1 protein content strongly correlated (r = 0.93) with citrate synthase activity in skeletal muscle (P < 0.05). In conclusion, endurance training markedly increased skeletal muscle LKB1 and MO25 protein without increasing AMPKK activity. LKB1 may be playing multiple roles in skeletal muscle adaptation to endurance training.
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Affiliation(s)
- E B Taylor
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah 84602, USA
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140
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Vogelmann R, Nelson WJ. Fractionation of the epithelial apical junctional complex: reassessment of protein distributions in different substructures. Mol Biol Cell 2004; 16:701-16. [PMID: 15548593 PMCID: PMC545905 DOI: 10.1091/mbc.e04-09-0827] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The epithelial apical junctional complex (AJC) is an important regulator of cell structure and function. The AJC is compartmentalized into substructures comprising the tight and adherens junctions, and other membrane complexes containing the membrane proteins nectin, junctional adhesion molecule, and crumbs. In addition, many peripheral membrane proteins localize to the AJC. Studies of isolated proteins indicate a complex map of potential binding partners in which there is extensive overlap in the interactions between proteins in different AJC substructures. As an alternative to a direct search for specific protein-protein interactions, we sought to separate membrane substructures of the AJC in iodixanol density gradients and define their protein constituents. Results show that the AJC can be fractured into membrane substructures that contain specific membrane and peripheral membrane proteins. The composition of each substructure reveals a more limited overlap in common proteins than predicted from the inventory of potential interactions; some of the overlapping proteins may be involved in stepwise recruitment and assembly of AJC substructures.
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Affiliation(s)
- Roger Vogelmann
- Department of Molecular and Cellular Physiology, Beckman Center for Molecular and Genetic Medicine, Stanford University School of Medicine, Stanford, CA 94305-5435, USA
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141
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Jin J, Smith FD, Stark C, Wells CD, Fawcett JP, Kulkarni S, Metalnikov P, O'Donnell P, Taylor P, Taylor L, Zougman A, Woodgett JR, Langeberg LK, Scott JD, Pawson T. Proteomic, functional, and domain-based analysis of in vivo 14-3-3 binding proteins involved in cytoskeletal regulation and cellular organization. Curr Biol 2004; 14:1436-50. [PMID: 15324660 DOI: 10.1016/j.cub.2004.07.051] [Citation(s) in RCA: 340] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Revised: 07/14/2004] [Accepted: 07/14/2004] [Indexed: 12/17/2022]
Abstract
BACKGROUND 14-3-3 proteins are abundant and conserved polypeptides that mediate the cellular effects of basophilic protein kinases through their ability to bind specific peptide motifs phosphorylated on serine or threonine. RESULTS We have used mass spectrometry to analyze proteins that associate with 14-3-3 isoforms in HEK293 cells. This identified 170 unique 14-3-3-associated proteins, which show only modest overlap with previous 14-3-3 binding partners isolated by affinity chromatography. To explore this large set of proteins, we developed a domain-based hierarchical clustering technique that distinguishes structurally and functionally related subsets of 14-3-3 target proteins. This analysis revealed a large group of 14-3-3 binding partners that regulate cytoskeletal architecture. Inhibition of 14-3-3 phosphoprotein recognition in vivo indicates the general importance of such interactions in cellular morphology and membrane dynamics. Using tandem proteomic and biochemical approaches, we identify a phospho-dependent 14-3-3 binding site on the A kinase anchoring protein (AKAP)-Lbc, a guanine nucleotide exchange factor (GEF) for the Rho GTPase. 14-3-3 binding to AKAP-Lbc, induced by PKA, suppresses Rho activation in vivo. CONCLUSION 14-3-3 proteins can potentially engage around 0.6% of the human proteome. Domain-based clustering has identified specific subsets of 14-3-3 targets, including numerous proteins involved in the dynamic control of cell architecture. This notion has been validated by the broad inhibition of 14-3-3 phosphorylation-dependent binding in vivo and by the specific analysis of AKAP-Lbc, a RhoGEF that is controlled by its interaction with 14-3-3.
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Affiliation(s)
- Jing Jin
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
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142
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Kusakabe M, Nishida E. The polarity-inducing kinase Par-1 controls Xenopus gastrulation in cooperation with 14-3-3 and aPKC. EMBO J 2004; 23:4190-201. [PMID: 15343271 PMCID: PMC524384 DOI: 10.1038/sj.emboj.7600381] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Accepted: 08/03/2004] [Indexed: 11/09/2022] Open
Abstract
Par (partitioning-defective) genes were originally identified in Caenorhabditis elegans as determinants of anterior/posterior polarity. However, neither their function in vertebrate development nor their action mechanism has been fully addressed. Here we show that two members of Par proteins, 14-3-3 (Par-5) and atypical PKC (aPKC), regulate the serine/threonine kinase Par-1 to control Xenopus gastrulation. We find first that Xenopus Par-1 (xPar-1) is essential for gastrulation but not for cell fate specification during early embryonic development. We then find that xPar-1 binds to 14-3-3 in an aPKC-dependent manner. Our analyses identify two aPKC phosphorylation sites in xPar-1, which are essential for 14-3-3 binding and for proper gastrulation movements. The aPKC phosphorylation-dependent binding of xPar-1 to 14-3-3 does not markedly affect the kinase activity of xPar-1, but induces relocation of xPar-1 from the plasma membranes to the cytoplasm. Finally, we show that Xenopus aPKC and its binding partner Xenopus Par-6 are also essential for gastrulation. Thus, our results identify a requirement of Par proteins for Xenopus gastrulation and reveal a novel interrelationship within Par proteins that may provide a general mechanism for spatial control of Par-1.
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Affiliation(s)
- Morioh Kusakabe
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Eisuke Nishida
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, Japan
- Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. Tel.: +81 75 753 4230; Fax: +81 75 753 4235; E-mail:
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143
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Abstract
LKB1, the product of a tumour suppressor gene, is a serine/threonine kinase that coordinates disparate cellular processes. Recent data have revealed novel functions for LKB1, providing new insight into the regulation of cell polarity and energy-generating metabolism.
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Affiliation(s)
- James Spicer
- Department of Medical Oncology, Guy's Hospital, St Thomas's Street, London SE1 9RT, UK
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144
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Lizcano JM, Göransson O, Toth R, Deak M, Morrice NA, Boudeau J, Hawley SA, Udd L, Mäkelä TP, Hardie DG, Alessi DR. LKB1 is a master kinase that activates 13 kinases of the AMPK subfamily, including MARK/PAR-1. EMBO J 2004; 23:833-43. [PMID: 14976552 PMCID: PMC381014 DOI: 10.1038/sj.emboj.7600110] [Citation(s) in RCA: 1085] [Impact Index Per Article: 54.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2003] [Accepted: 01/15/2004] [Indexed: 12/13/2022] Open
Abstract
We recently demonstrated that the LKB1 tumour suppressor kinase, in complex with the pseudokinase STRAD and the scaffolding protein MO25, phosphorylates and activates AMP-activated protein kinase (AMPK). A total of 12 human kinases (NUAK1, NUAK2, BRSK1, BRSK2, QIK, QSK, SIK, MARK1, MARK2, MARK3, MARK4 and MELK) are related to AMPK. Here we demonstrate that LKB1 can phosphorylate the T-loop of all the members of this subfamily, apart from MELK, increasing their activity >50-fold. LKB1 catalytic activity and the presence of MO25 and STRAD are required for activation. Mutation of the T-loop Thr phosphorylated by LKB1 to Ala prevented activation, while mutation to glutamate produced active forms of many of the AMPK-related kinases. Activities of endogenous NUAK2, QIK, QSK, SIK, MARK1, MARK2/3 and MARK4 were markedly reduced in LKB1-deficient cells. Neither LKB1 activity nor that of AMPK-related kinases was stimulated by phenformin or AICAR, which activate AMPK. Our results show that LKB1 functions as a master upstream protein kinase, regulating AMPK-related kinases as well as AMPK. Between them, these kinases may mediate the physiological effects of LKB1, including its tumour suppressor function.
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Affiliation(s)
- Jose M Lizcano
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Olga Göransson
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Rachel Toth
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Maria Deak
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Nick A Morrice
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Jérôme Boudeau
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Simon A Hawley
- Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Lina Udd
- Molecular Cancer Biology Program, Institute of Biomedicine and Helsinki University Central Hospital, Biomedicum Helsinki, University of Helsinki, Finland
| | - Tomi P Mäkelä
- Molecular Cancer Biology Program, Institute of Biomedicine and Helsinki University Central Hospital, Biomedicum Helsinki, University of Helsinki, Finland
| | - D Grahame Hardie
- Division of Molecular Physiology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Dario R Alessi
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK. Tel.: +44 1382 344 241; Fax: +44 1382 223 778; E-mail:
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