1
|
Robichaux WG, Cheng X. Intracellular cAMP Sensor EPAC: Physiology, Pathophysiology, and Therapeutics Development. Physiol Rev 2018; 98:919-1053. [PMID: 29537337 PMCID: PMC6050347 DOI: 10.1152/physrev.00025.2017] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 09/05/2017] [Accepted: 09/06/2017] [Indexed: 12/13/2022] Open
Abstract
This review focuses on one family of the known cAMP receptors, the exchange proteins directly activated by cAMP (EPACs), also known as the cAMP-regulated guanine nucleotide exchange factors (cAMP-GEFs). Although EPAC proteins are fairly new additions to the growing list of cAMP effectors, and relatively "young" in the cAMP discovery timeline, the significance of an EPAC presence in different cell systems is extraordinary. The study of EPACs has considerably expanded the diversity and adaptive nature of cAMP signaling associated with numerous physiological and pathophysiological responses. This review comprehensively covers EPAC protein functions at the molecular, cellular, physiological, and pathophysiological levels; and in turn, the applications of employing EPAC-based biosensors as detection tools for dissecting cAMP signaling and the implications for targeting EPAC proteins for therapeutic development are also discussed.
Collapse
Affiliation(s)
- William G Robichaux
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology, Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center , Houston, Texas
| |
Collapse
|
2
|
Jeske NA. Peripheral scaffolding and signaling pathways in inflammatory pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:31-52. [PMID: 25744669 DOI: 10.1016/bs.pmbts.2014.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Peripheral injury precipitates the release and accumulation of extracellular molecules at the site of injury. Although these molecules exist in various forms, they activate specific receptor classes expressed on primary afferent neurons to mediate cellular and behavioral responses to both nonpainful and painful stimuli. These inflammatory mediators and subsequent receptor-mediated effects exist to warn an organism of future injury, thereby resulting in protection and rehabilitation of the wounded tissue. In this chapter, inflammatory mediators, their target receptor classes, and downstream signaling pathways are identified and discussed within the context of inflammatory hyperalgesia. Furthermore, scaffolding mechanisms that exist to support inflammatory signaling in peripheral afferent neuronal tissues specifically are identified and discussed. Together, the mediators, pathways, and scaffolding mechanisms involved in inflammatory hyperalgesia provide a unique knowledge point from which new therapeutic targets can be understood.
Collapse
Affiliation(s)
- Nathaniel A Jeske
- Department of Oral and Maxillofacial Surgery, UT Health Science Center, San Antonio, Texas, USA.
| |
Collapse
|
3
|
Maurice DH, Ke H, Ahmad F, Wang Y, Chung J, Manganiello VC. Advances in targeting cyclic nucleotide phosphodiesterases. Nat Rev Drug Discov 2014; 13:290-314. [PMID: 24687066 DOI: 10.1038/nrd4228] [Citation(s) in RCA: 561] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants.
Collapse
Affiliation(s)
- Donald H Maurice
- Biomedical and Molecular Sciences, Queen's University, Kingston K7L3N6, Ontario, Canada
| | - Hengming Ke
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
| | - Faiyaz Ahmad
- Cardiovascular and Pulmonary Branch, The National Heart, Lung and Blood Institute, US National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Yousheng Wang
- Beijing Technology and Business University, Beijing 100048, China
| | - Jay Chung
- Genetics and Developmental Biology Center, The National Heart, Lung and Blood Institute, US National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Vincent C Manganiello
- Cardiovascular and Pulmonary Branch, The National Heart, Lung and Blood Institute, US National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
4
|
Nishimura T, Fujii W, Sugiura K, Naito K. Cytoplasmic Anchoring of cAMP-Dependent Protein Kinase (PKA) by A-Kinase Anchor Proteins (AKAPs) Is Required for Meiotic Arrest of Porcine Full-Grown and Growing Oocytes1. Biol Reprod 2014; 90:58. [DOI: 10.1095/biolreprod.113.114736] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
5
|
Nishimura T, Sugiura K, Naito K. A-kinase anchor protein 1 (AKAP1) regulates cAMP-dependent protein kinase (PKA) localization and is involved in meiotic maturation of porcine oocytes. Biol Reprod 2013; 88:85. [PMID: 23426434 DOI: 10.1095/biolreprod.112.106351] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In mammalian oocytes, cAMP-dependent protein kinase (PKA) has critical functions in meiotic arrest and meiotic maturation. Although subcellular localization of PKA is regulated by A-kinase anchor proteins (AKAPs) and PKA compartmentalization is essential for PKA functions, the role of AKAPs in meiotic regulation has not been fully elucidated. In the present study, we performed far-Western blot analysis using porcine PRKAR2A for detection of AKAPs and found, to our knowledge, several novel signals in porcine oocytes. Among these signals, a 150-kDa AKAP showed the major expression and was the product of porcine AKAP1. Overexpression of AKAP1 changed the PKA localization and promoted meiotic resumption of porcine oocytes even in the presence of a high concentration of cAMP, which inhibits meiotic resumption by inducing high PKA activity. On the contrary, knockdown of AKAP1 showed inhibitory effects on meiotic resumption and oocyte maturation. In addition, the expression level of AKAP1 in porcine growing oocytes, which show meiotic incompetence and PKA mislocalization, was significantly lower than that in fully grown oocytes. However, AKAP1 insufficiency was not the primary cause of the meiotic incompetence of the growing oocytes. These results suggest that the regulation of PKA localization by AKAP1 may be involved in meiotic resumption and oocyte maturation but not in meiotic incompetence of porcine growing oocytes.
Collapse
Affiliation(s)
- Takanori Nishimura
- Laboratory of Applied Genetics, Graduate School of Agriculture and Life Sciences, University of Tokyo, Tokyo, Japan
| | | | | |
Collapse
|
6
|
Lu Y, Zha XM, Kim EY, Schachtele S, Dailey ME, Hall DD, Strack S, Green SH, Hoffman DA, Hell JW. A kinase anchor protein 150 (AKAP150)-associated protein kinase A limits dendritic spine density. J Biol Chem 2011; 286:26496-506. [PMID: 21652711 DOI: 10.1074/jbc.m111.254912] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The A kinase anchor protein AKAP150 recruits the cAMP-dependent protein kinase (PKA) to dendritic spines. Here we show that in AKAP150 (AKAP5) knock-out (KO) mice frequency of miniature excitatory post-synaptic currents (mEPSC) and inhibitory post-synaptic currents (mIPSC) are elevated at 2 weeks and, more modestly, 4 weeks of age in the hippocampal CA1 area versus litter mate WT mice. Linear spine density and ratio of AMPAR to NMDAR EPSC amplitudes were also increased. Amplitude and decay time of mEPSCs, decay time of mIPSCs, and spine size were unaltered. Mice in which the PKA anchoring C-terminal 36 residues of AKAP150 are deleted (D36) showed similar changes. Furthermore, whereas acute stimulation of PKA (2-4 h) increases spine density, prolonged PKA stimulation (48 h) reduces spine density in apical dendrites of CA1 pyramidal neurons in organotypic slice cultures. The data from the AKAP150 mutant mice show that AKAP150-anchored PKA chronically limits the number of spines with functional AMPARs at 2-4 weeks of age. However, synaptic transmission and spine density was normal at 8 weeks in KO and D36 mice. Thus AKAP150-independent mechanisms correct the aberrantly high number of active spines in juvenile AKAP150 KO and D36 mice during development.
Collapse
Affiliation(s)
- Yuan Lu
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Lignitto L, Carlucci A, Sepe M, Stefan E, Cuomo O, Nisticò R, Scorziello A, Savoia C, Garbi C, Annunziato L, Feliciello A. Control of PKA stability and signalling by the RING ligase praja2. Nat Cell Biol 2011; 13:412-22. [PMID: 21423175 DOI: 10.1038/ncb2209] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 01/10/2011] [Indexed: 02/04/2023]
Abstract
Activation of G-protein-coupled receptors (GPCRs) mobilizes compartmentalized pulses of cyclic AMP. The main cellular effector of cAMP is protein kinase A (PKA), which is assembled as an inactive holoenzyme consisting of two regulatory (R) and two catalytic (PKAc) subunits. cAMP binding to R subunits dissociates the holoenzyme and releases the catalytic moiety, which phosphorylates a wide array of cellular proteins. Reassociation of PKAc and R components terminates the signal. Here we report that the RING ligase praja2 controls the stability of mammalian R subunits. Praja2 forms a stable complex with, and is phosphorylated by, PKA. Rising cAMP levels promote praja2-mediated ubiquitylation and subsequent proteolysis of compartmentalized R subunits, leading to sustained substrate phosphorylation by the activated kinase. Praja2 is required for efficient nuclear cAMP signalling and for PKA-mediated long-term memory. Thus, praja2 regulates the total concentration of R subunits, tuning the strength and duration of PKA signal output in response to cAMP.
Collapse
Affiliation(s)
- Luca Lignitto
- Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano, Universitá Federico II, 80131 Naples, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Goehring AS, Pedroja BS, Hinke SA, Langeberg LK, Scott JD. MyRIP anchors protein kinase A to the exocyst complex. J Biol Chem 2007; 282:33155-67. [PMID: 17827149 PMCID: PMC3508720 DOI: 10.1074/jbc.m705167200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The movement of signal transduction enzymes in and out of multi-protein complexes coordinates the spatial and temporal resolution of cellular events. Anchoring and scaffolding proteins are key to this process because they sequester protein kinases and phosphatases with a subset of their preferred substrates. The protein kinase A-anchoring family of proteins (AKAPs), which target the cAMP-dependent protein kinase (PKA) and other enzymes to defined subcellular microenvironments, represent a well studied group of these signal-organizing molecules. In this report we demonstrate that the Rab27a GTPase effector protein MyRIP is a member of the AKAP family. The zebrafish homolog of MyRIP (Ze-AKAP2) was initially detected in a two-hybrid screen for AKAPs. A combination of biochemical, cell-based, and immunofluorescence approaches demonstrate that the mouse MyRIP ortholog targets the type II PKA holoenzyme via an atypical mechanism to a specific perinuclear region of insulin-secreting cells. Similar approaches show that MyRIP interacts with the Sec6 and Sec8 components of the exocyst complex, an evolutionarily conserved protein unit that controls protein trafficking and exocytosis. These data indicate that MyRIP functions as a scaffolding protein that links PKA to components of the exocytosis machinery.
Collapse
Affiliation(s)
- April S. Goehring
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| | - Benjamin S. Pedroja
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| | - Simon A. Hinke
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| | - Lorene K. Langeberg
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| | - John D. Scott
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health & Science University, Portland, Oregon 97239
| |
Collapse
|
9
|
Scholten A, van Veen TAB, Vos MA, Heck AJR. Diversity of cAMP-Dependent Protein Kinase Isoforms and Their Anchoring Proteins in Mouse Ventricular Tissue. J Proteome Res 2007; 6:1705-17. [PMID: 17432891 DOI: 10.1021/pr060601a] [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: 11/29/2022]
Abstract
Using a chemical proteomics approach, we efficiently enriched for the generally low abundant cAMP signaling proteins, and their interactors, directly from mouse ventricular tissue. The presence of undesired contaminating (noncyclic) nucleotide-binding proteins was diminished using a tailored sequential elution protocol. Through further optimization of this affinity purification and elution protocol, we were able to detect all known protein kinase A regulatory isoforms (PKA-R). Furthermore, 11 different A-kinase anchoring proteins (AKAPs) were detected. A proposed fusion protein of paralemmin 2 and AKAP2 could be decisively established as a novel AKAP at the protein level in ventricular tissue. When comparing this dataset of cAMP-affinity purified proteins with earlier data obtained with immobilized cGMP from rat ventricular tissue, we observe a large overlap in the retained proteins but also some clear differences. Furthermore, implementation of an in-depth analysis of in vivo phosphorylation sites on PKA-R revealed the presence of several differentially phosphorylated PKA-R isoforms. This illustrates yet another layer of functional regulation in cyclic nucleotide signaling. In general, our improved chemical proteomics screen offers a broad, but detailed, view on nature's complex diversity in cyclic nucleotide signaling mechanisms. Possibly different AKAP-isoforms may direct differentially phosphorylated PKA-R isoforms to different cellular compartments, providing a multifaceted platform for just this kinase.
Collapse
Affiliation(s)
- Arjen Scholten
- Department of Biomolecular Mass Spectrometry, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
| | | | | | | |
Collapse
|
10
|
Ostroveanu A, Van der Zee EA, Dolga AM, Luiten PGM, Eisel ULM, Nijholt IM. A-kinase anchoring protein 150 in the mouse brain is concentrated in areas involved in learning and memory. Brain Res 2007; 1145:97-107. [PMID: 17321504 DOI: 10.1016/j.brainres.2007.01.117] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/26/2007] [Accepted: 01/29/2007] [Indexed: 11/16/2022]
Abstract
A-kinase anchoring proteins (AKAPs) form large macromolecular signaling complexes that specifically target cAMP-dependent protein kinase (PKA) to unique subcellular compartments and thus, provide high specificity to PKA signaling. For example, the AKAP79/150 family tethers PKA, PKC and PP2B to neuronal membranes and postsynaptic densities and plays an important role in synaptic function. Several studies suggested that AKAP79/150 anchored PKA contributes to mechanisms associated with synaptic plasticity and memory processes, but the precise role of AKAPs in these processes is still unknown. In this study we established the mouse brain distribution of AKAP150 using two well-characterized AKAP150 antibodies. Using Western blotting and immunohistochemistry we showed that AKAP150 is widely distributed throughout the mouse brain. The highest AKAP150 expression levels were observed in striatum, cerebral cortex and several other forebrain regions (e.g. olfactory tubercle), relatively high expression was found in hippocampus and olfactory bulb and low/no expression in cerebellum, hypothalamus, thalamus and brain stem. Although there were some minor differences in mouse AKAP150 brain distribution compared to the distribution in rat brain, our data suggested that rodents have a characteristic AKAP150 brain distribution pattern. In general we observed that AKAP150 is strongly expressed in mouse brain regions involved in learning and memory. These data support its suggested role in synaptic plasticity and memory processes.
Collapse
Affiliation(s)
- Anghelus Ostroveanu
- Department of Molecular Neurobiology, Graduate School of Behavioral and Cognitive Neurosciences, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands.
| | | | | | | | | | | |
Collapse
|
11
|
Ghil S, Choi JM, Kim SS, Lee YD, Liao Y, Birnbaumer L, Suh-Kim H. Compartmentalization of protein kinase A signaling by the heterotrimeric G protein Go. Proc Natl Acad Sci U S A 2006; 103:19158-63. [PMID: 17148597 PMCID: PMC1682014 DOI: 10.1073/pnas.0609392103] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
G(o), a member of the G(o/i) family, is the most abundant heterotrimeric G protein in brain. Most functions of G(o) are mediated by the G(betagamma) dimer; effector(s) for its alpha-subunit have not been clearly defined. Here we report that G(oalpha) interacts directly with cAMP-dependent protein kinase (PKA) through its GTPase domain. This interaction did not inhibit the kinase function of PKA but interfered with nuclear translocation of PKA while sparing its cytosolic function. This regulatory mechanism by which G(o) bifurcates PKA signaling may provide insights into how G(o) regulates complex processes such as neuritogenesis, synaptic plasticity, and cell transformation.
Collapse
Affiliation(s)
- Sungho Ghil
- Department of Biology, Kyonggi University, Suwon 442-760, South Korea
| | | | | | | | | | | | | |
Collapse
|
12
|
McConnachie G, Langeberg LK, Scott JD. AKAP signaling complexes: getting to the heart of the matter. Trends Mol Med 2006; 12:317-23. [PMID: 16809066 DOI: 10.1016/j.molmed.2006.05.008] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2006] [Revised: 04/25/2006] [Accepted: 05/30/2006] [Indexed: 01/18/2023]
Abstract
Subcellular compartmentalization of protein kinases and phosphatases through their interaction with A-kinase anchoring proteins (AKAPs) provides a mechanism to control signal transduction events at specific sites within the cell. Recent findings suggest that these anchoring proteins dynamically assemble different cAMP effectors to control the cellular actions of cAMP spatially and temporally. In the heart, signaling events such as the onset of cardiac hypertrophy are influenced by muscle-specific mAKAP signaling complexes that target protein kinase A (PKA), the cAMP-responsive guanine-nucleotide exchange factor EPAC and cAMP-selective phosphodiesterase 4 (PDE4). Mediation of signaling events by AKAPs might also have a role in the control of lipolysis in adipocytes, where insulin treatment reduces the association of AKAPs with G-protein-coupled receptors. These are only two examples of how AKAPs contribute to specificity in cAMP signaling. This review will explore recent development that illustrates the role of multiprotein complexes in the regulation of cAMP signaling.
Collapse
Affiliation(s)
- George McConnachie
- Howard Hughes Medical Institute, Vollum Institute, L-474, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97239, USA
| | | | | |
Collapse
|
13
|
Abstract
Multiprotein signalling networks create focal points of enzyme activity that disseminate the intracellular action of many hormones and neurotransmitters. Accordingly, the spatio-temporal activation of protein kinases and phosphatases is an important factor in controlling where and when phosphorylation events occur. Anchoring proteins provide a molecular framework that orients these enzymes towards selected substrates. A-kinase anchoring proteins (AKAPs) are signal-organizing molecules that compartmentalize various enzymes that are regulated by second messengers.
Collapse
Affiliation(s)
- Wei Wong
- Howard Hughes Medical Institute/Vollum Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, L-474, Portland, Oregon 97239, USA
| | | |
Collapse
|
14
|
Affiliation(s)
- Graeme K Carnegie
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health and Sciences University, Portland, Oregon 97201, USA
| | | |
Collapse
|
15
|
Dell'Acqua ML, Dodge KL, Tavalin SJ, Scott JD. Mapping the protein phosphatase-2B anchoring site on AKAP79. Binding and inhibition of phosphatase activity are mediated by residues 315-360. J Biol Chem 2002; 277:48796-802. [PMID: 12354762 PMCID: PMC3923414 DOI: 10.1074/jbc.m207833200] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Compartmentalization of protein kinases and phosphatases with substrates is a means to increase the efficacy of signal transduction events. The A-kinase anchoring protein, AKAP79, is a multivalent anchoring protein that maintains the cAMP-dependent protein kinase, protein kinase C, and protein phosphatase-2B (PP2B/calcineurin) at the postsynaptic membrane of excitatory synapses where it is recruited into complexes with N-methyl-d-aspartic acid or alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA)-subtype glutamate receptors. We have used cellular targeting of AKAP79 truncation and deletion mutants as an assay to map the PP2B-binding site on AKAP79. We demonstrate that residues 315-360 are necessary and sufficient for AKAP79-PP2B anchoring in cells. Multiple determinants contained within this region bind directly to the A subunit of PP2B and inhibit phosphatase activity. Peptides spanning the 315-360 region of AKAP79 can antagonize PP2B anchoring in vitro and targeting in transfected cells. Electrophysiological experiments further emphasize this point by demonstrating that a peptide encompassing residues 330-357 of AKAP79 attenuates PP2B-dependent down-regulation of GluR1 receptor currents when perfused into HEK293 cells. We propose that the structural features of this AKAP79-PP2B-binding domain may share similarities with other proteins that serve to coordinate PP2B localization and activity.
Collapse
Affiliation(s)
- Mark L. Dell'Acqua
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201
- Department of Pharmacology, School of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262
| | - Kimberly L. Dodge
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201
| | - Steven J. Tavalin
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201
| | - John D. Scott
- Howard Hughes Medical Institute, Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97201
- To whom correspondence should be addressed.
| |
Collapse
|
16
|
Mishra N, Khan IU, Tsokos GC, Kammer GM. Association of deficient type II protein kinase A activity with aberrant nuclear translocation of the RII beta subunit in systemic lupus erythematosus T lymphocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:2830-40. [PMID: 10946316 DOI: 10.4049/jimmunol.165.5.2830] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disorder of indeterminate etiology characterized by abnormal T cell signal transduction and altered T cell effector functions. We have previously observed a profound deficiency of total protein kinase A (PKA) phosphotransferase activity in SLE T cells. Here we examined whether reduced total PKA activity in SLE T cells is in part the result of deficient type II PKA (PKA-II) isozyme activity. The mean PKA-II activity in SLE T cells was 61% of normal control T cells. The prevalence of deficient PKA-II activity in 35 SLE subjects was 37%. Deficient isozyme activity was persistent over time and was unrelated to SLE disease activity. Reduced PKA-II activity was associated with spontaneous dissociation of the cytosolic RIIbeta2C2 holoenzyme and translocation of the regulatory (RIIbeta) subunit from the cytosol to the nucleus. Confocal immunofluorescence microscopy revealed that the RIIbeta subunit was present in approximately 60% of SLE T cell nuclei compared with only 2-3% of normal and disease controls. Quantification of nuclear RIIbeta subunit protein content by immunoprecipitation and immunoblotting demonstrated a 54% increase over normal T cell nuclei. Moreover, the RIIbeta subunit was retained in SLE T cell nuclei, failed to relocate to the cytosol, and was associated with a persistent deficiency of PKA-II activity. In conclusion, we describe a novel mechanism of deficient PKA-II isozyme activity due to aberrant nuclear translocation of the RIIbeta subunit and its retention in the nucleus in SLE T cells. Deficient PKA-II activity may contribute to impaired signaling in SLE T cells.
Collapse
Affiliation(s)
- N Mishra
- Section on Rheumatology and Clinical Immunology, Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | | | | | | |
Collapse
|
17
|
Angelo RG, Rubin CS. Characterization of structural features that mediate the tethering of Caenorhabditis elegans protein kinase A to a novel A kinase anchor protein. Insights into the anchoring of PKAI isoforms. J Biol Chem 2000; 275:4351-62. [PMID: 10660605 DOI: 10.1074/jbc.275.6.4351] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caenorhabditis elegans protein kinase A (PKAI(CE)) is tethered to organelles in vivo. A unique A kinase anchor protein (AKAP(CE)) avidly binds the RI-like regulatory subunits (R(CE)) of PKAI(CE) and stringently discriminates against RIIalpha and RIIbeta subunits, the preferred ligands for classical AKAPs. We elucidated structural features that stabilize AKAP(CE).R(CE) complexes and confer atypical R isoform specificity on the anchor protein. Three large aliphatic amino acids (Leu(236), Ile(248), and Leu(252)) in the tethering domain of AKAP(CE) (residues 236-255) are crucial for ligation of R(CE). Their side chains apparently generate a precisely configured hydrophobic binding pocket that accommodates an apolar surface on R(CE) dimers. Basic residues (His(254)-Arg(255)-Lys(256)) at the C terminus of the tethering site set an upper limit on affinity for R(CE.) A central dipeptide (Phe(243)-Ser(244)) contributes critical and distinctive properties of the tethering site. Ser(244) is essential for selective binding of R(CE) and exclusion of RII isoforms. The aromatic hydrophobic character of Phe(243) ensures maximal R(CE) binding activity, thereby supporting a "gatekeeper" function of Ser(244). Substitution of Phe(243)-Ser(244) with Leu-Val generated an RII-specific AKAP. R(CE) and RII subunits contain similar dimerization domains. AKAP-binding domains of R(CE) (residues 23-47) and RII differ markedly in size, amino acid sequence, and docking specificity. Four hydrophobic residues (Cys(23), Val(27), Ile(32), and Cys(44)) in R(CE) are crucial for avid binding with AKAP(CE), whereas side chains from Leu(20), Leu(35), Val(36), Ile(40), and Ile(41) have little impact on complex formation. Tyr(26) is embedded in the docking domain, but its aromatic ring is required for R(CE)-R(CE) dimerization. Residues 236-255 in AKAP(CE) also constitute a binding site for mammalian RIalpha. RIalpha (PKAIalpha) is tightly sequestered by AKAP(CE) in vitro (K(D) = approximately 10 nM) and in the environment of intact cells. The tethering domain of AKAP(CE) provides a molecular module for manipulating intracellular localization of RI and elucidating functions of anchored PKAI in eukaryotes.
Collapse
Affiliation(s)
- R G Angelo
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | |
Collapse
|
18
|
Davare MA, Dong F, Rubin CS, Hell JW. The A-kinase anchor protein MAP2B and cAMP-dependent protein kinase are associated with class C L-type calcium channels in neurons. J Biol Chem 1999; 274:30280-7. [PMID: 10514522 DOI: 10.1074/jbc.274.42.30280] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphorylation by cAMP-dependent protein kinase (PKA) increases the activity of class C L-type Ca(2+) channels which are clustered at postsynaptic sites and are important regulators of neuronal functions. We investigated a possible mechanism that could ensure rapid and efficient phosphorylation of these channels by PKA upon stimulation of cAMP-mediated signaling pathways. A kinase anchor proteins (AKAPs) bind to the regulatory R subunits of PKA and target the holoenzyme to defined subcellular compartments and substrates. Class C channels isolated from rat brain extracts by immunoprecipitation contain an endogenous kinase that phosphorylates kemptide, a classic PKA substrate peptide, and also the main phosphorylation site for PKA in the pore-forming alpha(1) subunit of the class C channel complex, serine 1928. The kinase activity is inhibited by the PKA inhibitory peptide PKI(5-24) and stimulated by cAMP. Physical association of the catalytic C subunit of PKA with the immunoisolated class C channel complex was confirmed by immunoblotting. A direct protein overlay binding assay performed with (32)P-labeled RIIbeta revealed a prominent AKAP with an M(r) of 280,000 in class C channel complexes. The protein was identified by immunoblotting as the microtubule-associated protein MAP2B, a well established AKAP. Class C channels did not contain tubulin and MAP2B association was not disrupted by dilution or addition of nocodazole, two treatments that cause dissociation of microtubules. In vitro experiments show that MAP2B can directly bind to the alpha(1) subunit of the class C channel. Our findings indicate that PKA is an integral part of neuronal class C L-type Ca(2+) channels and suggest that the AKAP MAP2B may mediate this interaction. Neither PKA nor MAP2B were detected in immunoprecipitates of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid-type glutamate receptors or class B N-type Ca(2+) channels. Accordingly, MAP2B docked at class C Ca(2+) channels may be important for recruiting PKA to postsynaptic sites.
Collapse
Affiliation(s)
- M A Davare
- Department of Pharmacology, University of Wisconsin, Madison, Wisconsin 53706-1532, USA
| | | | | | | |
Collapse
|
19
|
Miki K, Eddy EM. Single amino acids determine specificity of binding of protein kinase A regulatory subunits by protein kinase A anchoring proteins. J Biol Chem 1999; 274:29057-62. [PMID: 10506157 DOI: 10.1074/jbc.274.41.29057] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic AMP-dependent protein kinase is tethered to protein kinase A anchoring proteins (AKAPs) through regulatory subunits (R) by RIalpha-specific, RIIalpha-specific, or RIalpha/RIIalpha dual-specific binding. Ala- and Val-scanning mutagenesis determined that hydrophobic amino acids at three homologous positions are required for binding of RIalpha to FSC1/AKAP82 domain B and RIIalpha to AKAP Ht31. A mutation at the middle position reversed the binding specificity of both AKAPs, and mutations at this same position of the dual-specific domain A of FSC1/AKAP82 converted it into either an RIalpha or RIIalpha binding domain. This suggests that hydrophobic amino acids at three conserved positions within the primary sequence and an amphipathic helix of AKAPs are required for cyclic AMP-dependent protein kinase binding, with the size of the aliphatic side chain at the middle position determining RIalpha or RIIalpha binding specificity.
Collapse
Affiliation(s)
- K Miki
- Gamete Biology Section, Laboratory of Reproductive and Developmental Toxicology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | | |
Collapse
|
20
|
Li Z, Rossi EA, Hoheisel JD, Kalderon D, Rubin CS. Generation of a novel A kinase anchor protein and a myristoylated alanine-rich C kinase substrate-like analog from a single gene. J Biol Chem 1999; 274:27191-200. [PMID: 10480936 DOI: 10.1074/jbc.274.38.27191] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A unique Drosophila gene encodes two novel signaling proteins. Drosophila A kinase anchor protein 200 (DAKAP200) (753 amino acids) binds regulatory subunits of protein kinase AII (PKAII) isoforms in vitro and in intact cells. The acidic DAKAP200 polypeptide (pI approximately 3.8) contains an optimal N-terminal myristoylation site and a positively charged domain that resembles the multifunctional phosphorylation site domain of vertebrate myristoylated alanine-rich C kinase substrate proteins. The 15-kilobase pair DAKAP200 gene contains six exons and encodes a second protein, DeltaDAKAP200. DeltaDAKAP200 is derived from DAKAP200 transcripts by excision of exon 5 (381 codons), which encodes the PKAII binding region and a Pro-rich sequence. DeltaDAKAP200 appears to be a myristoylated alanine-rich C kinase substrate analog. DAKAP200 and DeltaDAKAP200 are evident in vivo at all stages of Drosophila development. Thus, both proteins may play important physiological roles throughout the life span of the organism. Nevertheless, DAKAP200 gene expression is regulated. Maximal levels of DAKAP200 are detected in the pupal phase of development; DeltaDAKAP200 content is elevated 7-fold in adult head (brain) relative to other body parts. Enhancement or suppression of exon 5 excision during DAKAP200 pre-mRNA processing provides potential mechanisms for regulating anchoring of PKAII and targeting of cAMP signals to effector sites in cytoskeleton and/or organelles.
Collapse
Affiliation(s)
- Z Li
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | |
Collapse
|
21
|
Rossi EA, Li Z, Feng H, Rubin CS. Characterization of the targeting, binding, and phosphorylation site domains of an A kinase anchor protein and a myristoylated alanine-rich C kinase substrate-like analog that are encoded by a single gene. J Biol Chem 1999; 274:27201-10. [PMID: 10480937 DOI: 10.1074/jbc.274.38.27201] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel Drosophila A kinase anchor protein, Drosophila A kinase anchor protein 200 (DAKAP200), is predicted to be involved in routing, mediating, and integrating signals carried by cAMP, Ca(2+), and diacylglycerol (Li, Z., Rossi, E. A., Hoheisel, J. D., Kalderon, D., and Rubin, C. S. (1999) J. Biol. Chem. 274, 27191-27200). Experiments designed to assess this hypothesis now (a) establish the function, boundaries and identity of critical amino acids of the protein kinase AII (PKAII) tethering site of DAKAP200; (b) demonstrate that residues 119-148 mediate binding with Ca(2+)-calmodulin and F-actin; (c) show that a polybasic region of DAKAP200 is a substrate for protein kinase C; (d) reveal that phosphorylation of the polybasic domain regulates affinity for F-actin and Ca(2+)-calmodulin; and (e) indicate that DAKAP200 is myristoylated and that this modification promotes targeting of DAKAP200 to plasma membrane. DeltaDAKAP200, a second product of the DAKAP200 gene, cannot tether PKAII. However, DeltaDAKAP200 is myristoylated and contains a phosphorylation site domain that binds Ca(2+)-calmodulin and F-actin. An atypical amino acid composition, a high level of negative charge, exceptional thermostability, unusual hydrodynamic properties, properties of the phosphorylation site domain, and a calculated M(r) of 38,000 suggest that DeltaDAKAP200 is a new member of the myristoylated alanine-rich C kinase substrate protein family. DAKAP200 is a potentially mobile, chimeric A kinase anchor protein-myristoylated alanine-rich C kinase substrate protein that may facilitate localized reception and targeted transmission of signals carried by cAMP, Ca(2+), and diacylglycerol.
Collapse
Affiliation(s)
- E A Rossi
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | |
Collapse
|
22
|
Francis SH, Corbin JD. Cyclic nucleotide-dependent protein kinases: intracellular receptors for cAMP and cGMP action. Crit Rev Clin Lab Sci 1999; 36:275-328. [PMID: 10486703 DOI: 10.1080/10408369991239213] [Citation(s) in RCA: 219] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Intracellular cAMP and cGMP levels are increased in response to a variety of hormonal and chemical stimuli; these nucleotides play key roles as second messenger signals in modulating myriad physiological processes. The cAMP-dependent protein kinase and cGMP-dependent protein kinase are major intracellular receptors for these nucleotides, and the actions of these enzymes account for much of the cellular responses to increased levels of cAMP or cGMP. This review summarizes many studies that have contributed significantly to an improved understanding of the catalytic, regulatory, and structural properties of these protein kinases. These accumulated findings provide insights into the mechanisms by which these enzymes produce their specific physiological effects and are helpful in considering the actions of other protein kinases as well.
Collapse
Affiliation(s)
- S H Francis
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615, USA
| | | |
Collapse
|
23
|
A Genetic Mechanism Underlying Deficient Type I Protein Kinase A Activity in Systemic Lupus Erythematosus T Lymphocytes. Lupus 1999. [DOI: 10.1007/978-1-59259-703-1_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
24
|
Angelo R, Rubin CS. Molecular characterization of an anchor protein (AKAPCE) that binds the RI subunit (RCE) of type I protein kinase A from Caenorhabditis elegans. J Biol Chem 1998; 273:14633-43. [PMID: 9603981 DOI: 10.1074/jbc.273.23.14633] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Classical A kinase anchor proteins (AKAPs) preferentially tether type II protein kinase A (PKAII) isoforms to sites in the cytoskeleton and organelles. It is not known if distinct proteins selectively sequester regulatory (R) subunits of type I PKAs, thereby diversifying functions of these critical enzymes. In Caenorhabditis elegans, a single type I PKA mediates all aspects of cAMP signaling. We have discovered a cDNA that encodes a binding protein (AKAPCE) for the regulatory subunit (RCE) of C. elegans PKAICE. AKAPCE is a novel, highly acidic RING finger protein composed of 1,280 amino acids. It binds RI-like RCE with high affinity and neither RIIalpha nor RIIbeta competitively inhibits formation of AKAPCE.RCE complexes. The RCE-binding site was mapped to a segment of 20 amino acids in an N-terminal region of AKAPCE. Several hydrophobic residues in the binding site align with essential Leu and Ile residues in the RII-selective tethering domain of prototypic mammalian AKAPs. However, the RCE-binding region in AKAPCE diverges sharply from consensus RII-binding sites by inclusion of three aromatic amino acids, exclusion of a highly conserved Leu or Ile at position 8 and replacement of C-terminal hydrophobic amino acids with basic residues. AKAPCE.RCE complexes accumulate in intact cells.
Collapse
Affiliation(s)
- R Angelo
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | |
Collapse
|
25
|
Dong F, Feldmesser M, Casadevall A, Rubin CS. Molecular characterization of a cDNA that encodes six isoforms of a novel murine A kinase anchor protein. J Biol Chem 1998; 273:6533-41. [PMID: 9497389 DOI: 10.1074/jbc.273.11.6533] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have cloned cDNA that encodes six novel A kinase anchor proteins (collectively named AKAP-KL). AKAP-KL diversity is generated by alternative mRNA splicing and utilization of two translation initiation codons. AKAP-KL polypeptides are evident in lung, kidney, and cerebellum, but are absent from many tissues. Different isoforms predominate in different tissues. Thus, AKAP-KL expression is differentially regulated in vivo. All AKAP-KL isoforms contain a 20-residue domain that avidly binds (Kd approximately 10 nM) regulatory subunits (RII) of protein kinase AII and is highly homologous with the RII tethering site in neuronal AKAP75. The distribution of AKAP-KL is strikingly asymmetric (polarized) in situ. Anchor protein accumulates near the inner, apical surface of highly polarized epithelium in tubules of nephrons. Both RII and AKAP-KL are enriched at an intracellular site that lies just below the plasma membrane of alveolar epithelial cells in lung. AKAP-KL interacts with and modulates the structure of the actin cytoskeleton in transfected cells. We also demonstrate that the tethering domain of AKAP-KL avidly ligates RII subunits in intact cells. AKAP-KL may be involved in (a) establishing polarity in signaling systems and (b) physically and functionally integrating PKAII isoforms with downstream effectors to capture, amplify, and precisely focus diffuse, trans-cellular signals carried by cAMP.
Collapse
Affiliation(s)
- F Dong
- Department of Molecular Pharmacology, Atran Laboratories, Bronx, New York 10461, USA
| | | | | | | |
Collapse
|
26
|
Han JD, Baker NE, Rubin CS. Molecular characterization of a novel A kinase anchor protein from Drosophila melanogaster. J Biol Chem 1997; 272:26611-9. [PMID: 9334242 DOI: 10.1074/jbc.272.42.26611] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Activation of protein kinase A (PKA) at discrete intracellular sites facilitates oogenesis and development in Drosophila. Thus, PKA-anchor protein complexes may be involved in controlling these crucial biological processes. Evaluation of this proposition requires knowledge of PKA binding/targeting proteins in the fly. We now report the discovery and characterization of cDNAs encoding a novel, Drosophila A kinase anchor protein, DAKAP550. DAKAP550 is a large (>2300 amino acids) acidic protein that is maximally expressed in anterior tissues. It binds regulatory subunits (RII) of both mammalian and Drosophila PKAII isoforms. The tethering region of DAKAP550 includes two proximal, but non-contiguous RII-binding sites (B1 and B2). The B1 domain (residues 1406-1425) binds RII approximately 20-fold more avidly than B2 (amino acids 1350-1369). Affinity-purified anti-DAKAP550 IgGs were exploited to demonstrate that the anchor protein is expressed in many cells in nearly all tissues throughout the lifespan of the fly. However, DAKAP550 is highly enriched and asymmetrically positioned in subpopulations of neurons and in apical portions of cells in gut and trachea. The combination of RII (PKAII) binding activity with differential expression and polarized localization is consistent with a role for DAKAP550 in creating target loci for the reception of signals carried by cAMP. The DAKAP550 gene was mapped to the 4F1.2 region of the X chromosome; flies that carry a deletion for this portion of the X chromosome lack DAKAP550 protein.
Collapse
Affiliation(s)
- J D Han
- Department of Molecular Pharmacology, Atran Laboratories, Bronx, New York 10461, USA
| | | | | |
Collapse
|
27
|
Chen Q, Lin RY, Rubin CS. Organelle-specific targeting of protein kinase AII (PKAII). Molecular and in situ characterization of murine A kinase anchor proteins that recruit regulatory subunits of PKAII to the cytoplasmic surface of mitochondria. J Biol Chem 1997; 272:15247-57. [PMID: 9182549 DOI: 10.1074/jbc.272.24.15247] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Experiments were designed to test the idea that A kinase anchor proteins (AKAPs) tether regulatory subunits (RII) of protein kinase AII (PKAII) isoforms to surfaces of organelles that are bounded by phospholipid bilayers. S-AKAP84, one of three RII-binding proteins encoded by a single-copy murine gene, was studied as a prototypic organelle-associated AKAP. When S-AKAP84 was expressed in HEK293 cells, the anchor protein was targeted to mitochondria and excluded from other cell compartments. The RII tethering site is located in the cytoplasm adjacent to the mitochondrial surface. Endogenous RII subunits are not associated with mitochondria isolated from control cells. Expression of S-AKAP84 in transfected HEK293 cells triggered a redistribution of 15% of total RII to mitochondria. Thus, the tethering region of the organelle-inserted anchor protein is properly oriented and avidly binds RII (PKAII) isoforms in intact cells. Two critical domains in S-AKAP84 were mapped. Residues 1 to 30 govern insertion of the polypeptide into the outer mitochondrial membrane; amino acids 306-325 constitute the RII-binding site. Properties established for S-AKAP84 in vitro and in situ strongly suggest that a physiological function of this protein is to concentrate and immobilize RII (PKAII) isoforms at the cytoplasmic face of a phospholipid bilayer.
Collapse
Affiliation(s)
- Q Chen
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | |
Collapse
|
28
|
Mei X, Singh IS, Erlichman J, Orr GA. Cloning and characterization of a testis-specific, developmentally regulated A-kinase-anchoring protein (TAKAP-80) present on the fibrous sheath of rat sperm. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 246:425-32. [PMID: 9208934 DOI: 10.1111/j.1432-1033.1997.t01-1-00425.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
cAMP is important for the initiation of mammalian sperm motility. Previously we established that a type II cAMP-dependent protein kinase is tightly associated with the fibrous sheath of rat sperm. This unique cytoskeletal structure surrounds the 9+2 axonemal network in the principal piece of the flagellum. Association of the kinase to the fibrous sheath is mediated via its regulatory subunit, RII. An RII-binding overlay procedure was used to document that RII could specifically associate with fibrous sheath polypeptides of 120 and 80 kDa. In this study, we report the cloning of a rat testis-specific, developmentally regulated, RII-binding protein (TAKAP-80). A 1.2-kb cDNA clone, isolated by screening a rat testis expression library with 32P-labeled RII, hybridized to a 1.8-kb mRNA transcript present exclusively in testis. This transcript appeared at detectable levels at 30 days after birth. Over the next 10 days the mRNA levels increased greatly. This time interval corresponds to the initiation of spermiogenesis. The complete nucleotide sequence of TAKAP-80 cDNA was obtained by polymerase chain reaction and contained a continuous open reading frame of 502 amino acids. The deduced amino acid sequence showed a clear demarcation of charged and hydrophobic amino acid residues. Amino acids 1-147 of the protein contained 45% charged residues, with lysine and arginine predominating. Similarly, amino acids 268-502 also contained a high percentage of charged amino acids (35%). In contrast, amino acids 148-267 were mostly hydrophobic and contained clusters of a repeating PXXP motif where X was predominantly valine and alanine or sometimes proline. The 1.2-kb cDNA clone was inserted into the pRSET vector and expressed as a His6 tag fusion protein in Escherichia coli. The recombinant protein was soluble and bound RIIalpha, RIIbeta and type IIalpha holoenzyme by the RII-binding overlay procedure. Deletion analysis revealed that the high-affinity interaction site for RII was contained within amino acids 258-378 of TAKAP-80. Antibodies prepared against the fusion protein recognized an 80-kDa protein present in the urea-insoluble particulate fraction of rat testis and in purified fibrous sheath preparations isolated from rat epididymal sperm. Levels of the 80-kDa immunoreactive protein were significantly higher in mature (60 days old) compared with immature (30 days old) rat testis, correlating with the mRNA levels.
Collapse
Affiliation(s)
- X Mei
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | | |
Collapse
|
29
|
Campos M, Fadden P, Alms G, Qian Z, Haystead TA. Identification of protein phosphatase-1-binding proteins by microcystin-biotin affinity chromatography. J Biol Chem 1996; 271:28478-84. [PMID: 8910475 DOI: 10.1074/jbc.271.45.28478] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Biotinylated microcystin was used to affinity purify over avidin-Sepharose the entire cellular content of active forms of protein phosphatase (PP) 1 and 2A holoenzymes present in three subcellular fractions of skeletal muscle. Biotinylated microcystin displayed IC50 values in the nM range against PP-1C (1.58 +/- 0.6 nM S.E., n = 3), PP-2AC (0.63 +/- 0.2 nM S.E., n = 3) and SMPP-1M (5.9 +/- 1.3 S.E., n = 3). Subsequent anion-exchange chromatography and SDS-polyacrylamide gel electrophoresis of the microcystin-biotin eluates of the three fractions revealed a complex pattern of proteins associated with PP-1C and PP-2AC. Far Western analysis and the rebinding interaction with recombinant PP-1C distinguished proteins in the eluates that bound PP-1C from those that bound PP-2AC. In Far Western analysis, 29 distinct proteins were identified to bind PP-1C. Significantly, these same proteins, plus seven others, were also recovered from the isothiocyanate eluates from microcystin-Sepharose by a rebinding interaction with PP-1C-microcystin-biotin. The number of proteins and range of novel molecular masses (18-125 kDa) identified to interact with PP-1C by these two techniques cannot be accounted for by the previously characterized subunits of PP-1. Our findings further support the concept that PP-1C is regulated in vivo by multiple and distinct substrate-targeting subunits.
Collapse
Affiliation(s)
- M Campos
- Department of Pharmacology, and Markey Center for Cell Signaling, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | | | | | | |
Collapse
|
30
|
Feliciello A, Giuliano P, Porcellini A, Garbi C, Obici S, Mele E, Angotti E, Grieco D, Amabile G, Cassano S, Li Y, Musti AM, Rubin CS, Gottesman ME, Avvedimento EV. The v-Ki-Ras oncogene alters cAMP nuclear signaling by regulating the location and the expression of cAMP-dependent protein kinase IIbeta. J Biol Chem 1996; 271:25350-9. [PMID: 8810300 DOI: 10.1074/jbc.271.41.25350] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The v-Ki-Ras oncoprotein dedifferentiates thyroid cells and inhibits nuclear accumulation of the catalytic subunit of cAMP-dependent protein kinase. After activation of v-Ras or protein kinase C, the regulatory subunit of type II protein kinase A, RIIbeta, translocates from the membranes to the cytosol. RIIbeta mRNA and protein were eventually depleted. These effects were mimicked by expressing AKAP45, a truncated version of the RII anchor protein, AKAP75. Because AKAP45 lacks membrane targeting domains, it induces the translocation of PKAII to the cytoplasm. Expression of AKAP45 markedly decreased thyroglobulin mRNA levels and inhibited accumulation of C-PKA in the nucleus. Our results suggest that: 1) The localization of PKAII influences cAMP signaling to the nucleus; 2) Ras alters the localization and the expression of PKAII; 3) Translocation of PKAII to the cytoplasm reduces nuclear C-PKA accumulation, resulting in decreased expression of cAMP-dependent genes, including RIIbeta, TSH receptor, and thyroglobulin. The loss of RIIbeta permanently down-regulates thyroid-specific gene expression.
Collapse
Affiliation(s)
- A Feliciello
- Dipartimento Biologia e Patologia Molecolare e Cellulare, Centro di Endocrinologia ed Oncologia Sperimentale del Consiglio Nazionale delle Ricerche, Facoltà di Medicina, Università Federico II, Napoli, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Li Y, Ndubuka C, Rubin CS. A kinase anchor protein 75 targets regulatory (RII) subunits of cAMP-dependent protein kinase II to the cortical actin cytoskeleton in non-neuronal cells. J Biol Chem 1996; 271:16862-9. [PMID: 8663279 DOI: 10.1074/jbc.271.28.16862] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Neuronal A kinase anchor protein (AKAP) homologs, such as AKAPs 75 and 150, tether cAMP-dependent protein kinase II (PKAII) isoforms to the postsynaptic cytoskeleton, thereby creating target sites for cAMP action. These AKAPs, which bind regulatory subunits (RIIs) of PKAII, are also expressed in certain non-neuronal cells. Non-neuronal cell lines that stably express wild type and mutant AKAP75 transgenes were generated to investigate the extraneuronal function of AKAPs. In non-neuronal cells, AKAP75 accumulates selectively in the actin-rich, cortical cytoskeleton in close proximity with the plasma membrane. AKAP75 efficiently sequesters cytoplasmic RIIalpha and RIIbeta (PKAII isoforms) and translocates these polypeptides to the cell cortex. Two structural modules in AKAP75, T1 (residues 27-48), and T2 (residues 77-100), are essential for targeting AKAP75.RII complexes to the cortical cytoskeleton. Deletions or amino acid substitutions in T1 and/or T2 result in the dispersion of both AKAP75 and RII subunits throughout the cytoplasm. AKAP75 is co-localized with F-actin and fodrin in the cortical cytoskeleton. Incubation of cells with 5 microM cytochalasin D disrupts actin filaments and dissociates actin from the cell cortex. In contrast, the bulk of AKAP75 and fodrin remain associated with the cortical region of cytochalasin D-treated cells. Thus, targeting of AKAP75 does not depend upon direct binding with F-actin. Rather, AKAP75 (like fodrin) may be associated with a multiprotein complex that interacts with integral plasma membrane proteins.
Collapse
Affiliation(s)
- Y Li
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | |
Collapse
|
32
|
Cao J, Fernández M, Ramos-Martínez JI, Villamarín JA. Identification of RII-binding proteins in the mollusc Mytilus galloprovincialis. FEBS Lett 1996; 382:93-6. [PMID: 8612771 DOI: 10.1016/0014-5793(96)00158-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several proteins with M(r) > 70 kDa from various tissues of the sea mussel Mytilus galloprovincialis were specifically recognized in vitro by the regulatory subunit (type RII alpha) of cAMP-dependent protein kinase (cAPK) from porcine heart. However, none of these proteins interacted with the regulatory subunit of cAPK from the mollusc itself. The results suggest that, unlike mammalian RII, regulatory subunit from mussel lacks the specific residues responsible for interaction with R-binding proteins. Consequently, the identified molluscan RII alpha-binding proteins should play a distinct role from cAPK anchoring.
Collapse
Affiliation(s)
- J Cao
- Departamento de Bioquímica e Bioloxía Molecular, Facultade de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
| | | | | | | |
Collapse
|
33
|
Lin RY, Moss SB, Rubin CS. Characterization of S-AKAP84, a novel developmentally regulated A kinase anchor protein of male germ cells. J Biol Chem 1995; 270:27804-11. [PMID: 7499250 DOI: 10.1074/jbc.270.46.27804] [Citation(s) in RCA: 150] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In mammalian spermatozoa, most of the type II alpha isoform of cAMP-dependent protein kinase (PKAII alpha) is anchored at the cytoplasmic surface of a specialized array of mitochondria in the flagellar cytoskeleton. This places the catalytic subunits of PKAII alpha in proximity with potential target substrates in the cytoskeleton. The mechanism by which PKAII alpha is anchored at the outer surface of germ cell mitochondria has not been elucidated. We now report the cloning of a cDNA that encodes a novel, germ cell A kinase anchor protein (AKAP) designated S-AKAP84. S-AKAP84 comprises 593 amino acids and contains a centrally located domain that avidly binds regulatory subunits (RII alpha and RII beta) of PKAII alpha and PKAII beta. The 3.2-kilobase S-AKAP84 mRNA and the cognate S-AKAP84 RII binding protein are expressed principally in the male germ cell lineage. Expression of S-AKAP84 is tightly regulated during development. The protein accumulates as spermatids undergo nuclear condensation and tail elongation. The timing of S-AKAP84 expression is correlated with the de novo accumulation of RII alpha and RII beta subunits and the migration of mitochondria from the cytoplasm (round spermatids) to the cytoskeleton (midpiece in elongating spermatids). Residues 1-30 at the NH2 terminus of S-AKAP84 constitute a putative signal/anchor sequence that may target the protein to the outer mitochondrial membrane. Immunofluorescence analysis demonstrated that S-AKAP84 is co-localized with mitochondria in the flagellum.
Collapse
Affiliation(s)
- R Y Lin
- Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | |
Collapse
|
34
|
Cho-Chung YS, Pepe S, Clair T, Budillon A, Nesterova M. cAMP-dependent protein kinase: role in normal and malignant growth. Crit Rev Oncol Hematol 1995; 21:33-61. [PMID: 8822496 DOI: 10.1016/1040-8428(94)00166-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Y S Cho-Chung
- Laboratory of Tumor Immunology and Biology, DCBDC, NCI, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
35
|
McNeill RB, Colbran RJ. Interaction of autophosphorylated Ca2+/calmodulin-dependent protein kinase II with neuronal cytoskeletal proteins. Characterization of binding to a 190-kDa postsynaptic density protein. J Biol Chem 1995; 270:10043-9. [PMID: 7730306 DOI: 10.1074/jbc.270.17.10043] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Subcellular localization of Ca2+/calmodulin-dependent protein kinase II (CaMKII) by interaction with specific anchoring proteins may be an important mechanism contributing to the regulation of CaMKII. Proteins capable of binding CaMKII were identified by the use of a gel overlay assay with recombinant mouse CaMKII alpha (mCaMKII alpha) or Xenopus CaMKII beta (xCaMKII beta) 32P-autophosphorylated at Thr286/287 as a probe. Numerous [32P]CaMKII-binding proteins were identified in various whole rat tissue extracts, but binding was most prominent to forebrain proteins of 190 kDa (p190) and 140 kDa (p140). Fractionation of forebrain extracts localized p190 and p140 to a crude particulate/cytoskeletal fraction and isolated postsynaptic densities. [32P]m-CaMKII alpha-bound to p190 with an apparent Kd of 609 nM (subunit concentration) and a Bmax of 7.0 pmol of mCaMKII alpha subunit bound per mg of P2 protein, as measured using the overlay assay. Binding of 100 nM [32P]m-CaMKII alpha to p190 was competed by nonradioactive mCaMKII alpha autophosphorylated on Thr286 (EC50% = 200 nM), but to a much lesser extent by nonradioactive mCaMKII alpha autophosphorylated on Thr306 (EC50% > 2000 nM). In addition, nonphosphorylated mCaMKII alpha was a poor competitor for [32P]mCaMKII alpha binding to p190. The competition data indicate that Ca2+/CaM-dependent autophosphorylation at Thr286 promotes binding to p190, whereas, Ca2+/CaM-independent autophosphorylation at Thr306 does not enhance binding. Therefore, CaMKII may become localized to postsynaptic densities by p190 following its activation by an increase of dendritic Ca2+ concentration.
Collapse
Affiliation(s)
- R B McNeill
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615, USA
| | | |
Collapse
|
36
|
Coghlan VM, Perrino BA, Howard M, Langeberg LK, Hicks JB, Gallatin WM, Scott JD. Association of protein kinase A and protein phosphatase 2B with a common anchoring protein. Science 1995; 267:108-11. [PMID: 7528941 DOI: 10.1126/science.7528941] [Citation(s) in RCA: 452] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Specificity of protein kinases and phosphatases may be achieved through compartmentalization with preferred substrates. In neurons, adenosine 3', 5'-monophosphate (cAMP)-dependent protein kinase (PKA) is localized at postsynaptic densities by association of its regulatory subunit with an A kinase anchor protein, AKAP79. Interaction cloning experiments demonstrated that AKAP79 also binds protein phosphatase 2B, or calcineurin (CaN). A ternary complex of PKA, AKAP, and CaN was isolated from bovine brain, and colocalization of the kinase and the phosphatase was established in neurites of cultured hippocampal neurons. The putative CaN-binding domain of AKAP79 is similar to that of the immunophilin FKBP-12, and AKAP79 inhibited CaN phosphatase activity. These results suggest that both PKA and CaN are targeted to subcellular sites by association with a common anchor protein and thereby regulate the phosphorylation state of key neuronal substrates.
Collapse
Affiliation(s)
- V M Coghlan
- Vollum Institute, Oregon Health Sciences University, Portland 97201
| | | | | | | | | | | | | |
Collapse
|
37
|
Li Y, Rubin CS. Mutagenesis of the Regulatory Subunit (RIIβ) of cAMP-dependent Protein Kinase IIβ Reveals Hydrophobic Amino Acids That Are Essential for RIIβ Dimerization and/or Anchoring RIIβ to the Cytoskeleton. J Biol Chem 1995. [DOI: 10.1074/jbc.270.4.1935] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
38
|
Type II regulatory subunit (RII) of the cAMP-dependent protein kinase interaction with A-kinase anchor proteins requires isoleucines 3 and 5. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)51074-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
39
|
MacMillan-Crow LA, Lincoln TM. High-affinity binding and localization of the cyclic GMP-dependent protein kinase with the intermediate filament protein vimentin. Biochemistry 1994; 33:8035-43. [PMID: 8025108 DOI: 10.1021/bi00192a007] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The major receptor protein for cyclic GMP (cGMP) in smooth muscle is the cGMP-dependent protein kinase (cGMP kinase). The more abundant I alpha isoform (subunit M(r) congruent to 78,000) of this enzyme mediates the effects of cGMP to relax contracted vascular smooth muscle preparations. In this study, we have addressed the hypothesis that the cGMP kinase is anchored to intracellular proteins which might serve to target cGMP kinase to protein substrates. Using a gel overlay technique, immunoprecipitation, and a fluorescence binding assay for cGMP kinase, we have identified vimentin as a high-affinity and specific binding protein for cGMP kinase. Binding of cGMP kinase to vimentin is reversible and stoichiometric (one cGMP kinase dimer/vimentin dimer) with a KD of approximately 49 nM. The site of high-affinity binding between cGMP kinase and vimentin did not appear to be localized to the catalytic domain of the kinase since vimentin phosphorylated by cGMP kinase and peptide substrates for cGMP kinase did not compete for high-affinity binding. Neither the proteolytically-derived 69-kDa catalytic fragment nor the 8-kDa N-terminal fragment bound vimentin with high affinity, suggesting that the cGMP kinase dimer was necessary for the interaction. Vimentin was readily phosphorylated in vitro with the dimer, but not the monomeric 69-kDa catalytic fragment even though the monomeric 69-kDa fragment was catalytically active toward other substrates such as histone F2b and peptides. This suggests that the high-affinity interaction between cGMP kinase and vimentin occurs at the N-terminal region, thus allowing the interaction between the phosphorylation site of vimentin and the catalytic site of cGMP kinase to occur.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- L A MacMillan-Crow
- Department of Pharmacology and Pathology, University of Alabama at Birmingham, 35294-0019
| | | |
Collapse
|
40
|
Structure and expression of a novel, neuronal protein kinase C (PKC1B) from Caenorhabditis elegans. PKC1B is expressed selectively in neurons that receive, transmit, and process environmental signals. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37099-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
41
|
A-KinaseAnchoringProteins: a key to selective activation of cAMP-responsive events? Mol Cell Biochem 1993. [DOI: 10.1007/bf01076780] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
42
|
Coghlan VM, Bergeson SE, Langeberg L, Nilaver G, Scott JD. A-kinase anchoring proteins: a key to selective activation of cAMP-responsive events? Mol Cell Biochem 1993; 127-128:309-19. [PMID: 7935359 DOI: 10.1007/978-1-4615-2600-1_28] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The cAMP-dependent protein kinase (PKA) regulates a variety of diverse biochemical events through the phosphorylation of target proteins. Because PKA is a multifunctional enzyme with a broad substrate specificity, its compartmentalization may be a key regulatory event in controlling which particular target substrates are phosphorylated. In recent years it has been demonstrated that differential localization of the type II holoenzyme is directed through interaction of the regulatory subunit (RII) with a family of A-Kinase Anchoring Proteins (AKAPs). In this report, we review evidence for PKA compartmentalization and discuss the structural and functional properties of AKAPs.
Collapse
Affiliation(s)
- V M Coghlan
- Vollum Institute of Advanced Biomedical Research, Oregon Health Sciences University, Portland 97201
| | | | | | | | | |
Collapse
|
43
|
Hubbard MJ, Cohen P. On target with a new mechanism for the regulation of protein phosphorylation. Trends Biochem Sci 1993; 18:172-7. [PMID: 8392229 DOI: 10.1016/0968-0004(93)90109-z] [Citation(s) in RCA: 659] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
There is overwhelming evidence that the reversible phosphorylation of proteins regulates most aspects of cell life. However, the broad specificities displayed by many protein phosphatases and kinases in vitro dictates that their activities be strictly regulated in vivo. Recent evidence indicates that a novel class of proteins, known as targetting subunits, specifies the location, catalytic and regulatory properties of protein phosphatases and kinases, and thereby plays a key role in ensuring the fidelity of protein phosphorylation.
Collapse
Affiliation(s)
- M J Hubbard
- Department of Biochemistry, University of Otago, New Zealand
| | | |
Collapse
|
44
|
Ndubuka C, Li Y, Rubin C. Expression of a kinase anchor protein 75 depletes type II cAMP-dependent protein kinases from the cytoplasm and sequesters the kinases in a particulate pool. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)52999-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
45
|
Perez J, Tinelli D, Cagnoli C, Pecin P, Brunello N, Racagni G. Evidence for the existence of cAMP-dependent protein kinase phosphorylation system associated with specific phosphoproteins in stable microtubules from rat cerebral cortex. Brain Res 1993; 602:77-83. [PMID: 8448660 DOI: 10.1016/0006-8993(93)90244-h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cyclic AMP is a second messenger by which different extracellular signals are transduced into biological responses. Within the cell, most of the effects of cAMP are mediated through the cAMP protein kinase which appears to be localized in specific compartments of the cell near to their substrate proteins. In the present study, we have investigated the possible association of cAMP-dependent protein kinase, its substrate proteins and RII binding proteins in stable microtubules from rat cerebral cortex. The results show that in this fraction there is a cAMP binding protein of 52-54 kDa. This cAMP receptor is in the inactive holoenzyme form, since the addition of cAMP (5 microM) induces an increase in the endogenous phosphorylation of different stable microtubules polypeptides, which is completely inhibited in the presence of a specific protein kinase inhibitor (PKI 5-24 1 microM). Interestingly, overlay binding assay reveals that beside MAP2, 32P/R II is able to bind stable microtubule proteins of M(r) 150 and 75 kDa which, according to their electrophoretic mobility, can also be endogenous substrates for the enzyme. We conclude that cAMP-dependent phosphorylation system is indeed associated with stable microtubules from rat cerebral cortex.
Collapse
Affiliation(s)
- J Perez
- Center for Neuropharmacology, Institute of Pharmacological Sciences, Milano, Italy
| | | | | | | | | | | |
Collapse
|
46
|
Alessi D, MacDougall LK, Sola MM, Ikebe M, Cohen P. The control of protein phosphatase-1 by targetting subunits. The major myosin phosphatase in avian smooth muscle is a novel form of protein phosphatase-1. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 210:1023-35. [PMID: 1336455 DOI: 10.1111/j.1432-1033.1992.tb17508.x] [Citation(s) in RCA: 297] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The major protein phosphatase that dephosphorylates smooth-muscle myosin was purified from chicken gizzard myofibrils and shown to be composed of three subunits with apparent molecular masses of 130, 37 and 20 kDa, the most likely structure being a heterotrimer. The 37-kDa component was the catalytic subunit, while the 130-kDa and 20-kDa components formed a regulatory complex that enhanced catalytic subunit activity towards heavy meromyosin or the isolated myosin P light chain from smooth muscle and suppressed its activity towards phosphorylase, phosphorylase kinase and glycogen synthase. The catalytic subunit was identified as the beta isoform of protein phosphatase-1 (PP1) and the 130-kDa subunit as the PP1-binding component. The distinctive properties of smooth and skeletal muscle myosin phosphatases are explained by interaction of PP1 beta with different proteins and (in conjunction with earlier analysis of the glycogen-associated phosphatase) establish that the specificity and subcellular location of PP1 is determined by its interaction with a number of specific targetting subunits.
Collapse
Affiliation(s)
- D Alessi
- Department of Biochemistry, University of Dundee, Scotland
| | | | | | | | | |
Collapse
|
47
|
Localization of the cAMP-dependent protein kinase to the postsynaptic densities by A-kinase anchoring proteins. Characterization of AKAP 79. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41856-x] [Citation(s) in RCA: 213] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
48
|
Carr DW, Scott JD. Blotting and band-shifting: techniques for studying protein-protein interactions. Trends Biochem Sci 1992; 17:246-9. [PMID: 1323890 DOI: 10.1016/0968-0004(92)90402-u] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The type II cAMP-dependent protein kinase (PKA) is localized in certain cellular compartments through association with specific A-kinase anchoring proteins (AKAPs). A variety of blotting and electrophoresis techniques have been developed to study the protein-protein interactions that occur between the regulatory (R) subunit of PKA and AKAPs. These methods have also been used for a variety of purposes such as detecting calmodulin-binding proteins, comparing wild-type- and mutant-form binding affinities and estimating the molecular weight of multiprotein complexes.
Collapse
Affiliation(s)
- D W Carr
- Vollum Institute for Advanced Biomedical Research, Portland, OR 97201-3089
| | | |
Collapse
|
49
|
Carr D, Hausken Z, Fraser I, Stofko-Hahn R, Scott J. Association of the type II cAMP-dependent protein kinase with a human thyroid RII-anchoring protein. Cloning and characterization of the RII-binding domain. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42221-1] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
50
|
Hirsch AH, Glantz SB, Li Y, You Y, Rubin CS. Cloning and expression of an intron-less gene for AKAP 75, an anchor protein for the regulatory subunit of cAMP-dependent protein kinase II beta. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)45852-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|