1
|
Kovanich D, Low TY, Zaccolo M. Using the Proteomics Toolbox to Resolve Topology and Dynamics of Compartmentalized cAMP Signaling. Int J Mol Sci 2023; 24:4667. [PMID: 36902098 PMCID: PMC10003371 DOI: 10.3390/ijms24054667] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/04/2023] Open
Abstract
cAMP is a second messenger that regulates a myriad of cellular functions in response to multiple extracellular stimuli. New developments in the field have provided exciting insights into how cAMP utilizes compartmentalization to ensure specificity when the message conveyed to the cell by an extracellular stimulus is translated into the appropriate functional outcome. cAMP compartmentalization relies on the formation of local signaling domains where the subset of cAMP signaling effectors, regulators and targets involved in a specific cellular response cluster together. These domains are dynamic in nature and underpin the exacting spatiotemporal regulation of cAMP signaling. In this review, we focus on how the proteomics toolbox can be utilized to identify the molecular components of these domains and to define the dynamic cellular cAMP signaling landscape. From a therapeutic perspective, compiling data on compartmentalized cAMP signaling in physiological and pathological conditions will help define the signaling events underlying disease and may reveal domain-specific targets for the development of precision medicine interventions.
Collapse
Affiliation(s)
- Duangnapa Kovanich
- Center for Vaccine Development, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Teck Yew Low
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics and Oxford NIHR Biomedical Research Centre, University of Oxford, Oxford OX1 3PT, UK
| |
Collapse
|
2
|
Abstract
Many kinases use reversible docking interactions to augment the specificity of their catalytic domains. Such docking interactions are often structurally independent of the catalytic domain, which allow for a flexible combination of modules in evolution and in bioengineering. The affinity of docking interactions spans several orders of magnitude. This led us to ask how the affinity of the docking interaction affects enzymatic activity and how to pick the optimal interaction module to complement a given substrate. Here, we develop equations that predict the optimal binding strength of a kinase docking interaction and validate it using numerical simulations and steady-state phosphorylation kinetics for tethered protein kinase A. We show that a kinase-substrate pair has an optimum docking strength that depends on their enzymatic constants, the tether architecture, the substrate concentration, and the kinetics of the docking interactions. We show that a reversible tether enhances phosphorylation rates most when 1) the docking strength is intermediate, 2) the substrate is nonoptimal, 3) the substrate concentration is low, 4) the docking interaction has rapid exchange kinetics, and 5) the tether optimizes the effective concentration of the intramolecular reaction. This work serves as a framework for interpreting mutations in kinase docking interactions and as a design guide for engineering enzyme scaffolds.
Collapse
|
3
|
Sherpa RT, Fiore C, Moshal KS, Wadsworth A, Rudokas MW, Agarwal SR, Harvey RD. Mitochondrial A-kinase anchoring proteins in cardiac ventricular myocytes. Physiol Rep 2021; 9:e15015. [PMID: 34514737 PMCID: PMC8436057 DOI: 10.14814/phy2.15015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 12/30/2022] Open
Abstract
Compartmentation of cAMP signaling is a critical factor for maintaining the integrity of receptor-specific responses in cardiac myocytes. This phenomenon relies on various factors limiting cAMP diffusion. Our previous work in adult rat ventricular myocytes (ARVMs) indicates that PKA regulatory subunits anchored to the outer membrane of mitochondria play a key role in buffering the movement of cytosolic cAMP. PKA can be targeted to discrete subcellular locations through the interaction of both type I and type II regulatory subunits with A-kinase anchoring proteins (AKAPs). The purpose of this study is to identify which AKAPs and PKA regulatory subunit isoforms are associated with mitochondria in ARVMs. Quantitative PCR data demonstrate that mRNA for dual specific AKAP1 and 2 (D-AKAP1 & D-AKAP2), acyl-CoA-binding domain-containing 3 (ACBD3), optic atrophy 1 (OPA1) are most abundant, while Rab32, WAVE-1, and sphingosine kinase type 1 interacting protein (SPHKAP) were barely detectable. Biochemical and immunocytochemical analysis suggests that D-AKAP1, D-AKAP2, and ACBD3 are the predominant mitochondrial AKAPs exposed to the cytosolic compartment in these cells. Furthermore, we show that both type I and type II regulatory subunits of PKA are associated with mitochondria. Taken together, these data suggest that D-AKAP1, D-AKAP2, and ACBD3 may be responsible for tethering both type I and type II PKA regulatory subunits to the outer mitochondrial membrane in ARVMs. In addition to regulating PKA-dependent mitochondrial function, these AKAPs may play an important role by buffering the movement of cAMP necessary for compartmentation.
Collapse
Affiliation(s)
| | - Chase Fiore
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
| | | | - Adam Wadsworth
- Department of PharmacologyUniversity of NevadaRenoNevadaUSA
| | | | | | | |
Collapse
|
4
|
Colombe AS, Pidoux G. Cardiac cAMP-PKA Signaling Compartmentalization in Myocardial Infarction. Cells 2021; 10:cells10040922. [PMID: 33923648 PMCID: PMC8073060 DOI: 10.3390/cells10040922] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/02/2021] [Accepted: 04/13/2021] [Indexed: 02/07/2023] Open
Abstract
Under physiological conditions, cAMP signaling plays a key role in the regulation of cardiac function. Activation of this intracellular signaling pathway mirrors cardiomyocyte adaptation to various extracellular stimuli. Extracellular ligand binding to seven-transmembrane receptors (also known as GPCRs) with G proteins and adenylyl cyclases (ACs) modulate the intracellular cAMP content. Subsequently, this second messenger triggers activation of specific intracellular downstream effectors that ensure a proper cellular response. Therefore, it is essential for the cell to keep the cAMP signaling highly regulated in space and time. The temporal regulation depends on the activity of ACs and phosphodiesterases. By scaffolding key components of the cAMP signaling machinery, A-kinase anchoring proteins (AKAPs) coordinate both the spatial and temporal regulation. Myocardial infarction is one of the major causes of death in industrialized countries and is characterized by a prolonged cardiac ischemia. This leads to irreversible cardiomyocyte death and impairs cardiac function. Regardless of its causes, a chronic activation of cardiac cAMP signaling is established to compensate this loss. While this adaptation is primarily beneficial for contractile function, it turns out, in the long run, to be deleterious. This review compiles current knowledge about cardiac cAMP compartmentalization under physiological conditions and post-myocardial infarction when it appears to be profoundly impaired.
Collapse
|
5
|
Pelizzo G, Chiricosta L, Mazzon E, Zuccotti GV, Avanzini MA, Croce S, Lima M, Bramanti P, Calcaterra V. Discovering Genotype Variants in an Infant with VACTERL through Clinical Exome Sequencing: A Support for Personalized Risk Assessment and Disease Prevention. Pediatr Rep 2021; 13:45-56. [PMID: 33466296 PMCID: PMC7838983 DOI: 10.3390/pediatric13010006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/24/2020] [Accepted: 12/31/2020] [Indexed: 12/20/2022] Open
Abstract
Congenital anomalies may have an increased risk of noncommunicable diseases (NCDs) We performed a clinical exome analysis in an infant affected by "Vertebral, Anorectal, Cardiac, Tracheoesophageal, Genitourinary, and Limb" (VACTERL) malformation association to identify potential biomarkers that may be helpful for preventing malignancy risk or other chronic processes. Among the variants, six variants that may be linked with VACTERL were identified in the exome analysis. The variants c.501G>C on OLR1 and c.-8C>G on PSMA6 were previously associated with myocardial infarction. The variants c.1936A>G on AKAP10 and c.575A>G on PON1 are linked to defects in cardiac conduction and artery disease, respectively. Alterations in metabolism were also suggested by the variants c.860G>A on EPHX2 and c.214C>A on GHRL. In addition, three variants associated with colon cancer were discovered. Specifically, the reported variants were c.723G>A on CCND1 and c.91T>A on AURKA proto-oncogenes as well as c.827A>C in the tumor suppressor PTPRJ. A further inspection identified 15 rare variants carried by cancer genes. Specifically, these mutations are located on five tumor suppressors (SDHA, RB1CC1, PTCH1, DMBT1, BCR) and eight proto-oncogenes (MERTK, CSF1R, MYB, ROS1, PCM1, FGFR2, MYH11, BRCC3) and have an allele frequency lower than 0.01 in the Genome Aggregation Database (GnomAD). We observed that the cardiac and metabolic phenotypic traits are linked with the genotype of the patient. In addition, the risk of developing neoplasia cannot be excluded a priori. Long-term surgical issues of patients with VATER syndrome could benefit from the clinical exome sequencing of a personalized risk assessment for the appearance of further disease in pubertal timing and adult age.
Collapse
Affiliation(s)
- Gloria Pelizzo
- Pediatric Surgery Unit, Ospedale dei Bambini “Vittore Buzzi”, 20154 Milano, Italy
- Department of Biomedical and Clinical Science “L. Sacco”, University of Milano, 20157 Milano, Italy;
- Correspondence:
| | - Luigi Chiricosta
- IRCCS Centro Neurolesi “Bonino-Pulejo”, 98124 Messina, Italy; (L.C.); (E.M.); (P.B.)
| | - Emanuela Mazzon
- IRCCS Centro Neurolesi “Bonino-Pulejo”, 98124 Messina, Italy; (L.C.); (E.M.); (P.B.)
| | - Gian Vincenzo Zuccotti
- Department of Biomedical and Clinical Science “L. Sacco”, University of Milano, 20157 Milano, Italy;
- Department of Pediatrics, Ospedale dei Bambini “Vittore Buzzi”, 20154 Milano, Italy;
| | - Maria Antonietta Avanzini
- Immunology and Transplantation Laboratory, Cell Factory, Pediatric Hematology Oncology Unit, Department of Maternal and Children’s Health, Fondazione IRCCS Policlinico S. Matteo, 27100 Pavia, Italy; (M.A.A.); (S.C.)
| | - Stefania Croce
- Immunology and Transplantation Laboratory, Cell Factory, Pediatric Hematology Oncology Unit, Department of Maternal and Children’s Health, Fondazione IRCCS Policlinico S. Matteo, 27100 Pavia, Italy; (M.A.A.); (S.C.)
| | - Mario Lima
- Pediatric Surgery Unit, S. Orsola Hospital, University of Bologna, 40138 Bologna, Italy;
| | - Placido Bramanti
- IRCCS Centro Neurolesi “Bonino-Pulejo”, 98124 Messina, Italy; (L.C.); (E.M.); (P.B.)
| | - Valeria Calcaterra
- Department of Pediatrics, Ospedale dei Bambini “Vittore Buzzi”, 20154 Milano, Italy;
- Pediatrics and Adolescentology Unit, Department of Internal Medicine, University of Pavia, 27100 Pavia, Italy
| |
Collapse
|
6
|
Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions.
Collapse
Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
7
|
Single nucleotide polymorphisms alter kinase anchoring and the subcellular targeting of A-kinase anchoring proteins. Proc Natl Acad Sci U S A 2018; 115:E11465-E11474. [PMID: 30455320 DOI: 10.1073/pnas.1816614115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A-kinase anchoring proteins (AKAPs) shape second-messenger signaling responses by constraining protein kinase A (PKA) at precise intracellular locations. A defining feature of AKAPs is a helical region that binds to regulatory subunits (RII) of PKA. Mining patient-derived databases has identified 42 nonsynonymous SNPs in the PKA-anchoring helices of five AKAPs. Solid-phase RII binding assays confirmed that 21 of these amino acid substitutions disrupt PKA anchoring. The most deleterious side-chain modifications are situated toward C-termini of AKAP helices. More extensive analysis was conducted on a valine-to-methionine variant in the PKA-anchoring helix of AKAP18. Molecular modeling indicates that additional density provided by methionine at position 282 in the AKAP18γ isoform deflects the pitch of the helical anchoring surface outward by 6.6°. Fluorescence polarization measurements show that this subtle topological change reduces RII-binding affinity 8.8-fold and impairs cAMP responsive potentiation of L-type Ca2+ currents in situ. Live-cell imaging of AKAP18γ V282M-GFP adducts led to the unexpected discovery that loss of PKA anchoring promotes nuclear accumulation of this polymorphic variant. Targeting proceeds via a mechanism whereby association with the PKA holoenzyme masks a polybasic nuclear localization signal on the anchoring protein. This led to the discovery of AKAP18ε: an exclusively nuclear isoform that lacks a PKA-anchoring helix. Enzyme-mediated proximity-proteomics reveal that compartment-selective variants of AKAP18 associate with distinct binding partners. Thus, naturally occurring PKA-anchoring-defective AKAP variants not only perturb dissemination of local second-messenger responses, but also may influence the intracellular distribution of certain AKAP18 isoforms.
Collapse
|
8
|
Biernawska J, Solek-Pastuszka J, Kazimierczak A, Safranow K, Kaczmarczyk M, Zegan-Baranska M, Zukowski M, Kotfis K. Predisposition of functional genetic variants of A-kinase anchoring protein 10 toward acquired repolarization disorders in high-risk vascular surgery patients. Ther Clin Risk Manag 2018; 14:1315-1322. [PMID: 30100729 PMCID: PMC6067797 DOI: 10.2147/tcrm.s167086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose We aimed at assessing the predisposition of A-kinase anchoring protein 10 (AKAP10) polymorphism toward acquired repolarization disorders in high-risk vascular surgery patients. Patients and methods One hundred adult patients (age =44–85 years), scheduled for an elective high-risk “open” vascular surgery procedure, were recruited. The electrocardiogram Holter monitor was used to assess repolarization stability from the beginning of the operation up to 24 hours afterward. The AKAP10 gene rs203462 polymorphism and cardiac complications were analyzed. Results Repolarization disturbances defined as QT interval duration corrected for heart rate (QTc) interval prolongation >500 ms and QTc interval dispersion >65 ms were recorded in 46 patients. A model of multivariate logistic regression showed that only the presence of allele G of the AKAP10 polymorphism was an independent risk factor for repolarization disturbances in the perioperative period (odds ratio =14.35; 95% CI =4.65–44.23; p<0.0001). Conclusion When the acquired QTc interval prolongation or QTc dispersion is associated with AKAP10 polymorphism, it may remain clinically silent.
Collapse
Affiliation(s)
- Jowita Biernawska
- Department of Anesthesiology and Intensive Therapy, Pomeranian Medical University, Szczecin, Poland,
| | - Joanna Solek-Pastuszka
- Department of Anesthesiology and Intensive Therapy, Pomeranian Medical University, Szczecin, Poland,
| | - Arkadiusz Kazimierczak
- Department of Angiology and Vascular Surgery, Pomeranian Medical University, Szczecin, Poland
| | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, Szczecin, Poland
| | - Mariusz Kaczmarczyk
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland
| | - Malgorzata Zegan-Baranska
- Department of Anesthesiology, Intensive Therapy and Acute Intoxications, Pomeranian Medical University, Szczecin, Poland
| | - Maciej Zukowski
- Department of Anesthesiology, Intensive Therapy and Acute Intoxications, Pomeranian Medical University, Szczecin, Poland
| | - Katarzyna Kotfis
- Department of Anesthesiology, Intensive Therapy and Acute Intoxications, Pomeranian Medical University, Szczecin, Poland
| |
Collapse
|
9
|
Ercu M, Klussmann E. Roles of A-Kinase Anchoring Proteins and Phosphodiesterases in the Cardiovascular System. J Cardiovasc Dev Dis 2018; 5:jcdd5010014. [PMID: 29461511 PMCID: PMC5872362 DOI: 10.3390/jcdd5010014] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/16/2018] [Accepted: 02/18/2018] [Indexed: 12/13/2022] Open
Abstract
A-kinase anchoring proteins (AKAPs) and cyclic nucleotide phosphodiesterases (PDEs) are essential enzymes in the cyclic adenosine 3′-5′ monophosphate (cAMP) signaling cascade. They establish local cAMP pools by controlling the intensity, duration and compartmentalization of cyclic nucleotide-dependent signaling. Various members of the AKAP and PDE families are expressed in the cardiovascular system and direct important processes maintaining homeostatic functioning of the heart and vasculature, e.g., the endothelial barrier function and excitation-contraction coupling. Dysregulation of AKAP and PDE function is associated with pathophysiological conditions in the cardiovascular system including heart failure, hypertension and atherosclerosis. A number of diseases, including autosomal dominant hypertension with brachydactyly (HTNB) and type I long-QT syndrome (LQT1), result from mutations in genes encoding for distinct members of the two classes of enzymes. This review provides an overview over the AKAPs and PDEs relevant for cAMP compartmentalization in the heart and vasculature and discusses their pathophysiological role as well as highlights the potential benefits of targeting these proteins and their protein-protein interactions for the treatment of cardiovascular diseases.
Collapse
Affiliation(s)
- Maria Ercu
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin 13125, Germany.
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin (MDC), Berlin 13125, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Berlin 13347, Germany.
| |
Collapse
|
10
|
Suryavanshi SV, Jadhav SM, McConnell BK. Polymorphisms/Mutations in A-Kinase Anchoring Proteins (AKAPs): Role in the Cardiovascular System. J Cardiovasc Dev Dis 2018; 5:E7. [PMID: 29370121 PMCID: PMC5872355 DOI: 10.3390/jcdd5010007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 02/06/2023] Open
Abstract
A-kinase anchoring proteins (AKAPs) belong to a family of scaffolding proteins that bind to protein kinase A (PKA) by definition and a variety of crucial proteins, including kinases, phosphatases, and phosphodiesterases. By scaffolding these proteins together, AKAPs build a "signalosome" at specific subcellular locations and compartmentalize PKA signaling. Thus, AKAPs are important for signal transduction after upstream activation of receptors ensuring accuracy and precision of intracellular PKA-dependent signaling pathways. Since their discovery in the 1980s, AKAPs have been studied extensively in the heart and have been proven essential in mediating cyclic adenosine monophosphate (cAMP)-PKA signaling. Although expression of AKAPs in the heart is very low, cardiac-specific knock-outs of several AKAPs have a noteworthy cardiac phenotype. Moreover, single nucleotide polymorphisms and genetic mutations in crucial cardiac proteins play a substantial role in the pathophysiology of cardiovascular diseases (CVDs). Despite the significant role of AKAPs in the cardiovascular system, a limited amount of research has focused on the role of genetic polymorphisms and/or mutations in AKAPs in increasing the risk of CVDs. This review attempts to overview the available literature on the polymorphisms/mutations in AKAPs and their effects on human health with a special focus on CVDs.
Collapse
Affiliation(s)
- Santosh V Suryavanshi
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Texas Medical Center, Houston, TX 77204, USA.
| | - Shweta M Jadhav
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Texas Medical Center, Houston, TX 77204, USA.
| | - Bradley K McConnell
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston College of Pharmacy, Texas Medical Center, Houston, TX 77204, USA.
| |
Collapse
|
11
|
Chung J, Wittig JG, Ghamari A, Maeda M, Dailey TA, Bergonia H, Kafina MD, Coughlin EE, Minogue CE, Hebert AS, Li L, Kaplan J, Lodish HF, Bauer DE, Orkin SH, Cantor AB, Maeda T, Phillips JD, Coon JJ, Pagliarini DJ, Dailey HA, Paw BH. Erythropoietin signaling regulates heme biosynthesis. eLife 2017; 6. [PMID: 28553927 PMCID: PMC5478267 DOI: 10.7554/elife.24767] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 05/28/2017] [Indexed: 11/13/2022] Open
Abstract
Heme is required for survival of all cells, and in most eukaryotes, is produced through a series of eight enzymatic reactions. Although heme production is critical for many cellular processes, how it is coupled to cellular differentiation is unknown. Here, using zebrafish, murine, and human models, we show that erythropoietin (EPO) signaling, together with the GATA1 transcriptional target, AKAP10, regulates heme biosynthesis during erythropoiesis at the outer mitochondrial membrane. This integrated pathway culminates with the direct phosphorylation of the crucial heme biosynthetic enzyme, ferrochelatase (FECH) by protein kinase A (PKA). Biochemical, pharmacological, and genetic inhibition of this signaling pathway result in a block in hemoglobin production and concomitant intracellular accumulation of protoporphyrin intermediates. Broadly, our results implicate aberrant PKA signaling in the pathogenesis of hematologic diseases. We propose a unifying model in which the erythroid transcriptional program works in concert with post-translational mechanisms to regulate heme metabolism during normal development. DOI:http://dx.doi.org/10.7554/eLife.24767.001 Heme is an iron-containing compound that is important for all living things, from bacteria to humans. Our red blood cells use heme to carry oxygen and deliver it throughout the body. The amount of heme that is produced must be tightly regulated. Too little or too much heme in a person’s red blood cells can lead to blood-related diseases such as anemia and porphyria. Yet, while scientists knew the enzymes needed to make heme, they did not know how these enzymes were controlled. Now, Chung et al. show that an important signaling molecule called erythropoietin controls how much heme is produced when red blood cells are made. The experiments used a combination of red blood cells from humans and mice as well as zebrafish, which are useful model organisms because their blood develops in a similar way to humans. When Chung et al. inhibited components of erythropoietin signaling, heme production was blocked too and the red blood cells could not work properly. These new findings pave the way to look at human patients with blood-related disorders to determine if they have defects in the erythropoietin signaling cascade. In the future, this avenue of research might lead to better treatments for a variety of blood diseases in humans. DOI:http://dx.doi.org/10.7554/eLife.24767.002
Collapse
Affiliation(s)
- Jacky Chung
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
| | - Johannes G Wittig
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
| | - Alireza Ghamari
- Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, United States
| | - Manami Maeda
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
| | - Tamara A Dailey
- Department of Microbiology, University of Georgia, Athens, United States.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Hector Bergonia
- Division of Hematology and Hematologic Malignancies, University of Utah School of Medicine, Salt Lake City, United States
| | - Martin D Kafina
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
| | | | - Catherine E Minogue
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | | | - Liangtao Li
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, United States
| | - Jerry Kaplan
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, United States
| | - Harvey F Lodish
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, United States
| | - Daniel E Bauer
- Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - Stuart H Orkin
- Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - Alan B Cantor
- Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| | - Takahiro Maeda
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States
| | - John D Phillips
- Division of Hematology and Hematologic Malignancies, University of Utah School of Medicine, Salt Lake City, United States
| | - Joshua J Coon
- Genome Center of Wisconsin, Madison, United States.,Department of Chemistry, University of Wisconsin-Madison, Madison, United States.,Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, United States
| | - David J Pagliarini
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Harry A Dailey
- Department of Microbiology, University of Georgia, Athens, United States.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, United States
| | - Barry H Paw
- Division of Hematology, Brigham and Women's Hospital, Harvard Medical School, Boston, United States.,Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, United States
| |
Collapse
|
12
|
Genetic association of AKAP10 gene polymorphism with reduced risk of preterm birth. J Perinatol 2015; 35:700-4. [PMID: 26110499 DOI: 10.1038/jp.2015.68] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/19/2015] [Accepted: 04/14/2015] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Preterm birth (PTB) is a multifactorial complication in which genetic and environmental factors contribute to the phenotype. The AKAP10 protein encoded by AKAP10 gene has a vital role in the maintenance of myometrial quiescence and pregnancy. This study aimed to investigate whether polymorphisms in the AKAP10 gene are associated with the risk of PTB. STUDY DESIGN A total of 664 women (132 preterm and 532 term) with spontaneous singleton deliveries were genotyped for AKAP10 polymorphisms (rs119672, rs203462 and rs169412) using Sequenom MassARRAY platform. RESULT A significant association was observed between the CC and AC genotypes of AKAP10 rs169412 with reduced risk of PTB (CC: adjusted odds ratio (OR) 2.95, 95% confidence interval (CI): 1.23-7.09, P=0.016. AC: adjusted OR 3.46, 95% CI: 1.38-8.68, P=0.008), respectively. Following stratification by ethnicity, a significant association was observed between the AC and CC genotypes of rs169412 and term birth in the Malay ethnic subgroup. (CC: OR 2.9, 95% CI: 1.01-8.59, P=0.041. AC: OR 3.14, 95% CI: 1.04-9.54, P=0.043). A significant association was also observed between the CT genotypes of AKAP10 rs119672 with reduced risk of PTB deliveries (CT: OR 3.2, 95% CI: 1.06-9.76 P=0.007, TT: OR 2.8, 0.98-8.34, P =.0.015) Alternatively, there was no association between AKAP10 rs169412 and rs119672 polymorphisms with PTB in the Indians and Chinese ethnic groups. CONCLUSION This study indicates a significant association between the AKAP10 polymorphisms and reduced risk of PTB in the Malays. This demonstrates the potential role of AKAP10 polymorphisms in preterm complications.
Collapse
|
13
|
Łoniewska B, Kaczmarczyk M, Clark JS, Gorący I, Horodnicka-Józwa A, Ciechanowicz A. Association of functional genetic variants of A-kinase anchoring protein 10 with QT interval length in full-term Polish newborns. Arch Med Sci 2015; 11:149-54. [PMID: 25861302 PMCID: PMC4379355 DOI: 10.5114/aoms.2013.34172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 08/29/2012] [Accepted: 11/13/2012] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION A-Kinase Anchoring Proteins (AKAPs) coordinate the specificity of protein kinase A signaling by localizing the kinase to subcellular sites. The 1936G (V646) AKAP10 allele has been associated in adults with low cholinergic/vagus nerve sensitivity, shortened PR intervals in ECG recording and in newborns with increased blood pressure and higher cholesterol cord blood concentration. The aim of the study was to answer the question of whether 1936A > G AKAP10 polymorphism is associated with the newborn electrocardiographic variables. MATERIAL AND METHODS Electrocardiograms were recorded from 114 consecutive healthy Polish newborns (55 females, 59 males), born after 37 gestational weeks to healthy women with uncomplicated pregnancies. All recordings were made between 3(rd) and 7(th) day of life to avoid QT variability. The heart rate per minute and duration of PR, QRS, RR and QT intervals were usually measured. The ECGs were evaluated independently by three observers. At birth, cord blood of neonates was obtained for isolation of genomic DNA. RESULTS The distribution of anthropometric and electrocardiographic variables in our cohort approached normality (skewness < 2 for all variables). No significant differences in anthropometric variables and electrocardiographic traits with respect to AKAP10 genotype were found. Multiple regression analysis with adjustment for gender, gestational age and birth mass revealed that QTc interval in GG AKAP10 homozygotes was significantly longer, but in range, when compared with A alleles carriers (AA + AG, recessive mode of inheritance). No rhythm disturbances were observed. CONCLUSIONS Results demonstrate possible association between AKAP10 1936A > G variant and QTc interval in Polish newborns.
Collapse
Affiliation(s)
- Beata Łoniewska
- Department of Neonatal Disease, Pomeranian Medical University, Szczecin, Poland
| | - Mariusz Kaczmarczyk
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland
| | - Jeremy Simon Clark
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland
| | - Iwona Gorący
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland
| | - Anita Horodnicka-Józwa
- Department of Pediatrics, Endocrinology, Diabetology, Metabolic Diseases and Children's Cardiology, Pomeranian Medical University, Szczecin, Poland
| | - Andrzej Ciechanowicz
- Department of Clinical and Molecular Biochemistry, Pomeranian Medical University, Szczecin, Poland
| |
Collapse
|
14
|
Soni S, Scholten A, Vos MA, van Veen TAB. Anchored protein kinase A signalling in cardiac cellular electrophysiology. J Cell Mol Med 2014; 18:2135-46. [PMID: 25216213 PMCID: PMC4224547 DOI: 10.1111/jcmm.12365] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 06/10/2014] [Indexed: 01/13/2023] Open
Abstract
The cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) is an elementary molecule involved in both acute and chronic modulation of cardiac function. Substantial research in recent years has highlighted the importance of A-kinase anchoring proteins (AKAP) therein as they act as the backbones of major macromolecular signalling complexes of the β-adrenergic/cAMP/PKA pathway. This review discusses the role of AKAP-associated protein complexes in acute and chronic cardiac modulation by dissecting their role in altering the activity of different ion channels, which underlie cardiac action potential (AP) generation. In addition, we review the involvement of different AKAP complexes in mechanisms of cardiac remodelling and arrhythmias.
Collapse
Affiliation(s)
- Siddarth Soni
- Division of Heart & Lungs, Dept of Medical Physiology, University Medical Centre Utrecht, Utrecht, The Netherlands; Biomolecular Mass Spectrometry & Proteomics, Utrecht Institute for Pharmaceutical Sciences and Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands
| | | | | | | |
Collapse
|
15
|
Xu K, Qi H. Sperm-specific AKAP3 is a dual-specificity anchoring protein that interacts with both protein kinase a regulatory subunits via conserved N-terminal amphipathic peptides. Mol Reprod Dev 2014; 81:595-607. [PMID: 24687590 DOI: 10.1002/mrd.22329] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 03/22/2014] [Indexed: 11/06/2022]
Abstract
cAMP-dependent protein kinase A (PKA) plays important regulatory roles during mouse spermatogenesis. PKA-mediated signaling has been shown to regulate gene expression, chromatin condensation, capacitation, and motility during sperm development and behavior, although how PKA is regulated in spatiotemporal manners during spermatogenesis is not fully understood. In the present study, we found that PKA subunit isoforms are expressed and localized differently in meiotic and post-meiotic mouse spermatogenic cells. Regulatory subunit I alpha (RIα) is expressed in spermatocytes and round spermatids, where it is localized diffusely throughout the cytoplasm of cells. During late spermiogenesis, RIα abundance gradually decreases. On the other hand, RIIα is expressed constantly throughout meiotic and post-meiotic stages, and is associated with cytoskeletal structures. Among several A kinase anchoring proteins (AKAPs) expressed in the testis, sperm-specific AKAP3 can be found in the cytoplasm of elongating spermatids and interacts with RIα, as demonstrated by both in vivo and in vitro experiments. In mature sperm, AKAP3 is exclusively found in the principal piece of the flagellum, coincident with only RIIα. Mutagenesis experiments further showed that the preferential interactions of AKAP3 with PKA regulatory subunits are mediated by two highly conserved amphipathic peptides located in the N-terminal region of AKAP3. Thus, AKAP3 is a dual-specificity molecule that modulates PKA isotypes in a spatiotemporal manner during mouse spermatogenesis.
Collapse
Affiliation(s)
- Kaibiao Xu
- Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | | |
Collapse
|
16
|
Łoniewska B, Adler G, Gumprecht J, Grzeszczak W, Kaczmarczyk M, Bińczak-Kuleta A, Ciechanowicz A, Clark JS. 1936A→G (I646 V) polymorphism in the AKAP10 gene encoding A-kinase-anchoring protein 10 in very long-lived poles is similar to that in newborns. Exp Aging Res 2013; 38:584-92. [PMID: 23092224 DOI: 10.1080/0361073x.2012.726177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
UNLABELLED BACKGROUND/STUDY CONTEXT: The common 1936A→G transition (rs203462) in the AKAP10 gene encoding the A-kinase-anchoring protein 10 has been recently associated with negative prognosis in the aging European American population (60 to 79 years old). The aim of this study was to see the effects of this transition on allele frequency in very long-lived Poles. METHODS AKAP10 genotype and allele distributions were analyzed in Polish subjects: 148 nonagenarians (95 to 103 years old) and 200 healthy newborn controls, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Distributions were separated according to gender and χ(2) tests used to analyze possible differences. RESULTS No significant differences were found in genotype or allele distribution between the age groups, for either gender. Percentages of GG AKAP10 homozygotes were slightly greater in the very old subjects than in the newborns (12.2% vs. 9.0%, respectively), and the G allele percentages were very similar (males, 30.7% and 33.0%; females, 34.1% and 35.8%; respectively). CONCLUSION The authors conclude that differences in study results between European Americans (60 to 79 years old) and Poles (≥95 years old) result from either (1) geographical location; or (2) the influence of this polymorphism on groups of people differing in genetic background or environmental history; or (3) the time window affected, including extreme age. Further studies with full age-frequency distributions are needed to clarify these results.
Collapse
Affiliation(s)
- Beata Łoniewska
- Department of Neonatal Diseases, Pomeranian Medical University, Szczecin, Poland
| | | | | | | | | | | | | | | |
Collapse
|
17
|
A-Kinase Anchoring Proteins 10 Expression in Relation to 2073A/G Polymorphism and Tumor Progression in Patients with Colorectal Cancer. Pathol Oncol Res 2013; 19:521-7. [DOI: 10.1007/s12253-013-9612-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 02/11/2013] [Indexed: 11/26/2022]
|
18
|
Sivadas P, Dienes JM, St Maurice M, Meek WD, Yang P. A flagellar A-kinase anchoring protein with two amphipathic helices forms a structural scaffold in the radial spoke complex. ACTA ACUST UNITED AC 2013; 199:639-51. [PMID: 23148234 PMCID: PMC3494852 DOI: 10.1083/jcb.201111042] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amphipathic helices in the A-kinase anchoring protein RSP3 bind to spoke proteins involved in the assembly and modulation of the flagellar radial spoke complex, expanding the repertoire of these versatile helical protein motifs. A-kinase anchoring proteins (AKAPs) contain an amphipathic helix (AH) that binds the dimerization and docking (D/D) domain, RIIa, in cAMP-dependent protein kinase A (PKA). Many AKAPs were discovered solely based on the AH–RIIa interaction in vitro. An RIIa or a similar Dpy-30 domain is also present in numerous diverged molecules that are implicated in critical processes as diverse as flagellar beating, membrane trafficking, histone methylation, and stem cell differentiation, yet these molecules remain poorly characterized. Here we demonstrate that an AKAP, RSP3, forms a dimeric structural scaffold in the flagellar radial spoke complex, anchoring through two distinct AHs, the RIIa and Dpy-30 domains, in four non-PKA spoke proteins involved in the assembly and modulation of the complex. Interestingly, one AH can bind both RIIa and Dpy-30 domains in vitro. Thus, AHs and D/D domains constitute a versatile yet potentially promiscuous system for localizing various effector mechanisms. These results greatly expand the current concept about anchoring mechanisms and AKAPs.
Collapse
Affiliation(s)
- Priyanka Sivadas
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | | | | | | | | |
Collapse
|
19
|
Scott JD, Dessauer CW, Taskén K. Creating order from chaos: cellular regulation by kinase anchoring. Annu Rev Pharmacol Toxicol 2012; 53:187-210. [PMID: 23043438 DOI: 10.1146/annurev-pharmtox-011112-140204] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Second messenger responses rely on where and when the enzymes that propagate these signals become active. Spatial and temporal organization of certain signaling enzymes is controlled in part by A-kinase anchoring proteins (AKAPs). This family of regulatory proteins was originally classified on the basis of their ability to compartmentalize the cyclic adenosine monophosphate (cAMP)-dependent protein kinase (also known as protein kinase A, or PKA). However, it is now recognized that AKAPs position G protein-coupled receptors, adenylyl cyclases, G proteins, and their effector proteins in relation to protein kinases and signal termination enzymes such as phosphodiesterases and protein phosphatases. This arrangement offers a simple and efficient means to limit the scope, duration, and directional flow of information to sites deep within the cell. This review focuses on the pros and cons of reagents that define the biological role of kinase anchoring inside cells and discusses recent advances in our understanding of anchored second messenger signaling in the cardiovascular and immune systems.
Collapse
Affiliation(s)
- John D Scott
- Howard Hughes Medical Institute and Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
| | | | | |
Collapse
|
20
|
Tröger J, Moutty MC, Skroblin P, Klussmann E. A-kinase anchoring proteins as potential drug targets. Br J Pharmacol 2012; 166:420-33. [PMID: 22122509 DOI: 10.1111/j.1476-5381.2011.01796.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A-kinase anchoring proteins (AKAPs) crucially contribute to the spatial and temporal control of cellular signalling. They directly interact with a variety of protein binding partners and cellular constituents, thereby directing pools of signalling components to defined locales. In particular, AKAPs mediate compartmentalization of cAMP signalling. Alterations in AKAP expression and their interactions are associated with or cause diseases including chronic heart failure, various cancers and disorders of the immune system such as HIV. A number of cellular dysfunctions result from mutations of specific AKAPs. The link between malfunctions of single AKAP complexes and a disease makes AKAPs and their interactions interesting targets for the development of novel drugs. LINKED ARTICLES This article is part of a themed section on Novel cAMP Signalling Paradigms. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.166.issue-2.
Collapse
Affiliation(s)
- Jessica Tröger
- Max Delbrück Center for Molecular Medicine Berlin-Buch (MDC), Berlin, Germany Leibniz Institute for Molecular Pharmacology (FMP), Berlin, Germany
| | | | | | | |
Collapse
|
21
|
The DPY-30 domain and its flanking sequence mediate the assembly and modulation of flagellar radial spoke complexes. Mol Cell Biol 2012; 32:4012-24. [PMID: 22851692 DOI: 10.1128/mcb.06602-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RIIa is known as the dimerization and docking (D/D) domain of the cyclic AMP (cAMP)-dependent protein kinase. However, numerous molecules, including radial spoke protein 2 (RSP2) in Chlamydomonas flagella, also contain an RIIa or a similar DPY-30 domain. To elucidate new roles of D/D domain-containing proteins, we investigated a panel of RSP2 mutants. An RSP2 mutant had paralyzed flagella defective in RSP2 and multiple subunits near the spokehead. New transgenic strains lacking only the DPY-30 domain in RSP2 were also paralyzed. In contrast, motility was restored in strains that lacked only RSP2's calmodulin-binding C-terminal region. These cells swam normally in dim light but could not maintain typical swimming trajectories under bright illumination. In both deletion transgenic strains, the subunits near the spokehead were restored, but their firm attachment to the spokestalk required the DPY-30 domain. We postulate that the DPY-30-helix dimer is a conserved two-prong linker, required for normal motility, organizing duplicated subunits in the radial spoke stalk and formation of a symmetrical spokehead. Further, the dispensable calmodulin-binding region appears to fine-tune the spokehead for regulation of "steering" motility in the green algae. Thus, in general, D/D domains may function to localize molecular modules for both the assembly and modulation of macromolecular complexes.
Collapse
|
22
|
Łoniewska B, Kaczmarczyk M, Clark JS, Bińczak-Kuleta A, Adler G, Kordek A, Horodnicka-Józwa A, Dawid G, Rudnicki J, Ciechanowicz A. Association of 1936A > G inAKAP10(A-kinase anchoring protein 10) and blood pressure in Polish full-term newborns. Blood Press 2012; 22:51-6. [DOI: 10.3109/08037051.2012.701792] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
23
|
Cawley NX, Wetsel WC, Murthy SRK, Park JJ, Pacak K, Loh YP. New roles of carboxypeptidase E in endocrine and neural function and cancer. Endocr Rev 2012; 33:216-53. [PMID: 22402194 PMCID: PMC3365851 DOI: 10.1210/er.2011-1039] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 01/18/2012] [Indexed: 01/14/2023]
Abstract
Carboxypeptidase E (CPE) or carboxypeptidase H was first discovered in 1982 as an enkephalin-convertase that cleaved a C-terminal basic residue from enkephalin precursors to generate enkephalin. Since then, CPE has been shown to be a multifunctional protein that subserves many essential nonenzymatic roles in the endocrine and nervous systems. Here, we review the phylogeny, structure, and function of CPE in hormone and neuropeptide sorting and vesicle transport for secretion, alternative splicing of the CPE transcript, and single nucleotide polymorphisms in humans. With this and the analysis of mutant and knockout mice, the data collectively support important roles for CPE in the modulation of metabolic and glucose homeostasis, bone remodeling, obesity, fertility, neuroprotection, stress, sexual behavior, mood and emotional responses, learning, and memory. Recently, a splice variant form of CPE has been found to be an inducer of tumor growth and metastasis and a prognostic biomarker for metastasis in endocrine and nonendocrine tumors.
Collapse
Affiliation(s)
- Niamh X Cawley
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | |
Collapse
|
24
|
Łoniewska B, Clark JS, Kaczmarczyk M, Adler G, Biñczak-Kuleta A, Kordek A, Horodnicka-Józwa A, Dawid G, Rudnicki J, Ciechanowicz A. Possible counter effect in newborns of 1936A>G (I646V) polymorphism in the AKAP10 gene encoding A-kinase-anchoring protein 10. J Perinatol 2012; 32:230-4. [PMID: 21701445 DOI: 10.1038/jp.2011.85] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Cyclic adenosine monophosphate/protein kinase A (PKA) is important in embryonic development. The human AKAP10 gene is polymorphic: 1936A>G results in changes to a PKA-binding domain and increased targeting to mitochondria. Previous studies found G1936 as 'deleterious' in adults, and this study investigates whether this holds true in preterm birth. STUDY DESIGN Study group consisted of 80 preterm newborns (PTNs) born before the 38th gestation week. Control group consisted of 123 full-term healthy newborns born after the 37th gestation week with uncomplicated pregnancies. Genomic DNA was extracted from umbilical blood and AKAP10 genotypes were identified by PCR/restriction enzyme. RESULT Significant differences in frequencies of 1936A>G genotypes/alleles between both groups were found. PTNs had increased frequency (55%) of AA homozygotes (odds ratio, AA versus AG+GG: 2.63 (95% confidence interval: 1.33 to 5.20), P=0.006) after adjustments: mothers with previous PTNs, smoking, first pregnancy, first delivery and Cesarean section. CONCLUSION Results suggest G1936 is preventative factor against preterm birth, in contrast with previously asserted negative effects in adults.
Collapse
Affiliation(s)
- B Łoniewska
- Department of Neonatal Diseases, Pomeranian Medical University, Szczecin, Poland
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Zaccolo M. Spatial control of cAMP signalling in health and disease. Curr Opin Pharmacol 2011; 11:649-55. [PMID: 22000603 DOI: 10.1016/j.coph.2011.09.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 09/28/2011] [Accepted: 09/28/2011] [Indexed: 01/28/2023]
Abstract
The cyclic adenosine 3',5'-monophosphate signalling pathway is now recognised to transduce signals in a compartmentalised manner such that individual stimuli only engage a subset of the pathway components that are physically constrained within defined subcellular locales, thus resulting in a precise functional outcome. As we are starting to appreciate the complexity of the spatial organisation and of the temporal regulation of this pathway, it is becoming clear that disruption of local signalling may lead to pathology and that local manipulation of cAMP signals may offer alternative approaches to treat disease.
Collapse
Affiliation(s)
- Manuela Zaccolo
- University of Glasgow, Molecular Pharmacology Centre, Institute of Neuroscience & Psychology, Room 403, Davidson Building, University Avenue, Glasgow G12 8QQ, Scotland, UK.
| |
Collapse
|
26
|
Diviani D, Dodge-Kafka KL, Li J, Kapiloff MS. A-kinase anchoring proteins: scaffolding proteins in the heart. Am J Physiol Heart Circ Physiol 2011; 301:H1742-53. [PMID: 21856912 DOI: 10.1152/ajpheart.00569.2011] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The pleiotropic cyclic nucleotide cAMP is the primary second messenger responsible for autonomic regulation of cardiac inotropy, chronotropy, and lusitropy. Under conditions of prolonged catecholaminergic stimulation, cAMP also contributes to the induction of both cardiac myocyte hypertrophy and apoptosis. The formation of localized, multiprotein complexes that contain different combinations of cAMP effectors and regulatory enzymes provides the architectural infrastructure for the specialization of the cAMP signaling network. Scaffolds that bind protein kinase A are called "A-kinase anchoring proteins" (AKAPs). In this review, we discuss recent advances in our understanding of how PKA is compartmentalized within the cardiac myocyte by AKAPs and how AKAP complexes modulate cardiac function in both health and disease.
Collapse
Affiliation(s)
- Dario Diviani
- Département de Pharmacologie et de Toxicologie, Faculté de Biologie et Médecine, Université de Lausanne, Lausanne, Switzerland.
| | | | | | | |
Collapse
|
27
|
Aye TT, Soni S, van Veen TAB, van der Heyden MAG, Cappadona S, Varro A, de Weger RA, de Jonge N, Vos MA, Heck AJR, Scholten A. Reorganized PKA-AKAP associations in the failing human heart. J Mol Cell Cardiol 2011; 52:511-8. [PMID: 21712045 DOI: 10.1016/j.yjmcc.2011.06.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/20/2011] [Accepted: 06/02/2011] [Indexed: 10/18/2022]
Abstract
Here we reveal that the characterization of large-scale re-arrangements of signaling scaffolds induced by heart failure can serve as a novel concept to identify more specific therapeutic targets. In the mammalian heart, the cAMP pathway, with the cAMP-dependent protein kinase (PKA) in a central role, acts directly downstream of adrenergic receptors to mediate cardiac contractility and rhythm. Heart failure, characterized by severe alterations in adrenergic stimulation is, amongst other interventions, often treated with β-blockers. Contrasting results, however, have shown both beneficial and detrimental effects of decreased cAMP levels in failing hearts. We hypothesize that the origin of this behavior lies in the complex spatiotemporal organization of the regulatory subunit of PKA (PKA-R), which associates tightly with various A-kinase anchoring proteins (AKAPs) to specifically localize PKA's activity. Using chemical proteomics directly applied to human patient and control heart tissue we demonstrate that the association profile of PKA-R with several AKAPs is severely altered in the failing heart, for instance effecting the interaction between PKA and the novel AKAP SPHKAP was 6-fold upregulated upon failing heart conditions. Also a significant increase in captured cGMP-dependent protein kinase (PKG) and phosphodiesterase 2 (PDE2) was observed. The observed altered profiles can already explain many aspects of the aberrant cAMP-response in the failing human heart, validating that this dataset may provide a resource for several novel, more specific, treatment options. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
Collapse
Affiliation(s)
- Thin-Thin Aye
- Biomolecular Mass Spectrometry and Proteomics Group, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
HMMerThread: detecting remote, functional conserved domains in entire genomes by combining relaxed sequence-database searches with fold recognition. PLoS One 2011; 6:e17568. [PMID: 21423752 PMCID: PMC3053371 DOI: 10.1371/journal.pone.0017568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2010] [Accepted: 02/03/2011] [Indexed: 12/14/2022] Open
Abstract
Conserved domains in proteins are one of the major sources of functional information for experimental design and genome-level annotation. Though search tools for conserved domain databases such as Hidden Markov Models (HMMs) are sensitive in detecting conserved domains in proteins when they share sufficient sequence similarity, they tend to miss more divergent family members, as they lack a reliable statistical framework for the detection of low sequence similarity. We have developed a greatly improved HMMerThread algorithm that can detect remotely conserved domains in highly divergent sequences. HMMerThread combines relaxed conserved domain searches with fold recognition to eliminate false positive, sequence-based identifications. With an accuracy of 90%, our software is able to automatically predict highly divergent members of conserved domain families with an associated 3-dimensional structure. We give additional confidence to our predictions by validation across species. We have run HMMerThread searches on eight proteomes including human and present a rich resource of remotely conserved domains, which adds significantly to the functional annotation of entire proteomes. We find ∼4500 cross-species validated, remotely conserved domain predictions in the human proteome alone. As an example, we find a DNA-binding domain in the C-terminal part of the A-kinase anchor protein 10 (AKAP10), a PKA adaptor that has been implicated in cardiac arrhythmias and premature cardiac death, which upon stress likely translocates from mitochondria to the nucleus/nucleolus. Based on our prediction, we propose that with this HLH-domain, AKAP10 is involved in the transcriptional control of stress response. Further remotely conserved domains we discuss are examples from areas such as sporulation, chromosome segregation and signalling during immune response. The HMMerThread algorithm is able to automatically detect the presence of remotely conserved domains in proteins based on weak sequence similarity. Our predictions open up new avenues for biological and medical studies. Genome-wide HMMerThread domains are available at http://vm1-hmmerthread.age.mpg.de.
Collapse
|
29
|
Iwamoto K, Ueda J, Bundo M, Kojima T, Kato T. Survey of the effect of genetic variations on gene expression in human prefrontal cortex and its application to genetics of psychiatric disorders. Neurosci Res 2011; 70:238-42. [PMID: 21382426 DOI: 10.1016/j.neures.2011.02.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 02/24/2011] [Accepted: 02/24/2011] [Indexed: 01/19/2023]
Abstract
Identifying the genetic basis of gene expression variation in the human brain is important for understanding brain physiology and pathophysiology. We investigated the genetic basis of gene expression variation in human prefrontal cortex using single nucleotide polymorphisms (SNPs) and taking into consideration brain sample pH. From approximately 12,000 brain-expressed transcripts, we identified 187 cis-regulated transcripts. Some of the transcripts were identified as cis-regulated in the lymphoblastoid cells or lymphocytes, which suggests common cis-regulation across different tissues. Knowledge of genetic variations contributing to differences in gene expression in the brain would be particularly useful in the study of neuropsychiatric disorders in combination with a large-scale genome-wide association study. Using Wellcome Trust Case Control Consortium association study data, we identified SNPs associated with bipolar disorder and gene expression variation in the human brain. We found that SNPs in the AKAP10 and PRKCI genes are significantly associated with bipolar disorder and gene expression variation.
Collapse
Affiliation(s)
- Kazuya Iwamoto
- Laboratory for Molecular Dynamics of Mental Disorders, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | | | | | | | | |
Collapse
|
30
|
Genome-wide association study (GWAS)-identified disease risk alleles do not compromise human longevity. Proc Natl Acad Sci U S A 2010; 107:18046-9. [PMID: 20921414 DOI: 10.1073/pnas.1003540107] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A set of currently known alleles increasing the risk for coronary artery disease, cancer, and type 2 diabetes as identified by genome-wide association studies was tested for compatibility with human longevity. Here, we show that nonagenarian siblings from long-lived families and singletons older than 85 y of age from the general population carry the same number of disease risk alleles as young controls. Longevity in this study population is not compromised by the cumulative effect of this set of risk alleles for common disease.
Collapse
|
31
|
Patel HH, Hamuro LL, Chun BJ, Kawaraguchi Y, Quick A, Rebolledo B, Pennypacker J, Thurston J, Rodriguez-Pinto N, Self C, Olson G, Insel PA, Giles WR, Taylor SS, Roth DM. Disruption of protein kinase A localization using a trans-activator of transcription (TAT)-conjugated A-kinase-anchoring peptide reduces cardiac function. J Biol Chem 2010; 285:27632-40. [PMID: 20581396 DOI: 10.1074/jbc.m110.146589] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Localization of protein kinase A (PKA) via A-kinase-anchoring proteins (AKAPs) is important for cAMP responsiveness in many cellular systems, and evidence suggests that AKAPs play an important role in cardiac signaling. To test the importance of AKAP-mediated targeting of PKA on cardiac function, we designed a cell-permeable peptide, which we termed trans-activator of transcription (TAT)-AKAD for TAT-conjugated A-kinase-anchoring disruptor, using the PKA binding region of AKAP10 and tested the effects of this peptide in isolated cardiac myocytes and in Langendorff-perfused mouse hearts. We initially validated TAT-AKAD as a PKA localization inhibitor in cardiac myocytes by the use of confocal microscopy and cellular fractionation to show that treatment with the peptide disrupts type I and type II PKA regulatory subunits. Knockdown of PKA activity was demonstrated by decrease in phosphorylation of phospholamban and troponin I after beta-adrenergic stimulation in isolated myocytes. Treatment with TAT-AKAD reduced myocyte shortening and rates of contraction and relaxation. Injection of TAT-AKAD (1 microM), but not scrambled control peptide, into the coronary circulation of isolated perfused hearts rapidly (<1 min) and reversibly decreased heart rate and peak left ventricular developed pressure. TAT-AKAD also had a pronounced effect on developed pressure (-dP/dt), consistent with a delayed relaxation of the heart. The effects of TAT-AKAD on heart rate and contractility persisted in hearts pretreated with isoproterenol. Disruption of PKA localization with TAT-AKAD thus had negative effects on chronotropy, inotropy, and lusitropy, thereby indicating a key role for AKAP-targeted PKA in control of heart rate and contractile function.
Collapse
Affiliation(s)
- Hemal H Patel
- Department of Anesthesiology, University of California, San Diego, La Jolla, California 92093-0654, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Affiliation(s)
- John D Scott
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195, USA.
| | | |
Collapse
|
33
|
Structure of D-AKAP2:PKA RI complex: insights into AKAP specificity and selectivity. Structure 2010; 18:155-66. [PMID: 20159461 PMCID: PMC3090270 DOI: 10.1016/j.str.2009.12.012] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 12/17/2009] [Accepted: 12/29/2009] [Indexed: 01/07/2023]
Abstract
A-kinase anchoring proteins (AKAPs) regulate cyclic AMP-dependent protein kinase (PKA) signaling in space and time. Dual-specific AKAP 2 (D-AKAP2) binds to the dimerization/docking (D/D) domain of both RI and RII regulatory subunits of PKA with high affinity. Here we have determined the structures of the RIalpha D/D domain alone and in complex with D-AKAP2. The D/D domain presents an extensive surface for binding through a well-formed N-terminal helix, and this surface restricts the diversity of AKAPs that can interact. The structures also underscore the importance of a redox-sensitive disulfide in affecting AKAP binding. An unexpected shift in the helical register of D-AKAP2 compared to the RIIalpha:D-AKAP2 complex structure makes the mode of binding to RIalpha novel. Finally, the comparison allows us to deduce a molecular explanation for the sequence and spatial determinants of AKAP specificity.
Collapse
|
34
|
Mechanisms of protein kinase A anchoring. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 283:235-330. [PMID: 20801421 DOI: 10.1016/s1937-6448(10)83005-9] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP), which is produced by adenylyl cyclases following stimulation of G-protein-coupled receptors, exerts its effect mainly through the cAMP-dependent serine/threonine protein kinase A (PKA). Due to the ubiquitous nature of the cAMP/PKA system, PKA signaling pathways underlie strict spatial and temporal control to achieve specificity. A-kinase anchoring proteins (AKAPs) bind to the regulatory subunit dimer of the tetrameric PKA holoenzyme and thereby target PKA to defined cellular compartments in the vicinity of its substrates. AKAPs promote the termination of cAMP signals by recruiting phosphodiesterases and protein phosphatases, and the integration of signaling pathways by binding additional signaling proteins. AKAPs are a heterogeneous family of proteins that only display similarity within their PKA-binding domains, amphipathic helixes docking into a hydrophobic groove formed by the PKA regulatory subunit dimer. This review summarizes the current state of information on compartmentalized cAMP/PKA signaling with a major focus on structural aspects, evolution, diversity, and (patho)physiological functions of AKAPs and intends to outline newly emerging directions of the field, such as the elucidation of AKAP mutations and alterations of AKAP expression in human diseases, and the validation of AKAP-dependent protein-protein interactions as new drug targets. In addition, alternative PKA anchoring mechanisms employed by noncanonical AKAPs and PKA catalytic subunit-interacting proteins are illustrated.
Collapse
|
35
|
Eggers CT, Schafer JC, Goldenring JR, Taylor SS. D-AKAP2 interacts with Rab4 and Rab11 through its RGS domains and regulates transferrin receptor recycling. J Biol Chem 2009; 284:32869-80. [PMID: 19797056 PMCID: PMC2781703 DOI: 10.1074/jbc.m109.022582] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Dual-specific A-kinase-anchoring protein 2 (D-AKAP2/AKAP10), which interacts at its carboxyl terminus with protein kinase A and PDZ domain proteins, contains two tandem regulator of G-protein signaling (RGS) domains for which the binding partners have remained unknown. We show here that these RGS domains interact with Rab11 and GTP-bound Rab4, the first demonstration of RGS domains binding small GTPases. Rab4 and Rab11 help regulate membrane trafficking through the endocytic recycling pathways by recruiting effector proteins to specific membrane domains. Although D-AKAP2 is primarily cytosolic in HeLa cells, a fraction of the protein localizes to endosomes and can be recruited there to a greater extent by overexpression of Rab4 or Rab11. D-AKAP2 also regulates the morphology of the Rab11-containing compartment, with co-expression causing accumulation of both proteins on enlarged endosomes. Knockdown of D-AKAP2 by RNA interference caused a redistribution of both Rab11 and the constitutively recycling transferrin receptor to the periphery of cells. Knockdown also caused an increase in the rate of transferrin recycling, suggesting that D-AKAP2 promotes accumulation of recycling proteins in the Rab4/Rab11-positive endocytic recycling compartment.
Collapse
Affiliation(s)
- Christopher T Eggers
- Department of Pharmacology, University of California at San Diego, La Jolla, California 92093, USA
| | | | | | | |
Collapse
|
36
|
Neumann SA, Tingley WG, Conklin BR, Shrader CJ, Peet E, Muldoon MF, Jennings JR, Ferrell RE, Manuck SB. AKAP10 (I646V) functional polymorphism predicts heart rate and heart rate variability in apparently healthy, middle-aged European-Americans. Psychophysiology 2009; 46:466-72. [PMID: 19496216 DOI: 10.1111/j.1469-8986.2009.00802.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Previous evidence suggests that the dual-specific A kinase-anchoring protein 2 functional polymorphism (AKAP10 (A/G) I646V) influences heart rate (HR) and heart rate variability (HRV) in mice and humans (N=122) with cardiovascular disease. Here, we asked whether this AKAP10 variant predicts HR and HRV in a large sample of healthy humans. Resting HR and short-term time and frequency domain measures of HRV (5 min during paced and unpaced respiration conditions) were assessed in a U.S. community sample (N=1,033) of generally healthy men and women (age 30-54) of European ancestry. Each person was genotyped for the AKAP10 variant. As with previous work, the AKAP10 Val allele predicted greater resting HR (Paced p<.01; Unpaced p<.03) and diminished HRV (Paced ps <.05) suggesting that this variant may modulate the sensitivity of cardiac pacemaker cells to autonomic inputs, possibly conferring risk for arrhythmias and sudden cardiac death.
Collapse
|
37
|
Carnegie GK, Means CK, Scott JD. A-kinase anchoring proteins: from protein complexes to physiology and disease. IUBMB Life 2009; 61:394-406. [PMID: 19319965 DOI: 10.1002/iub.168] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein scaffold complexes are a key mechanism by which a common signaling pathway can serve many different functions. Sequestering a signaling enzyme to a specific subcellular environment not only ensures that the enzyme is near its relevant targets, but also segregates this activity to prevent indiscriminate phosphorylation of other substrates. One family of diverse, well-studied scaffolding proteins are the A-kinase anchoring proteins (AKAPs). These anchoring proteins form multi-protein complexes that integrate cAMP signaling with other pathways and signaling events. In this review, we focus on recent advances in the elucidation of AKAP function.
Collapse
Affiliation(s)
- Graeme K Carnegie
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, School of Medicine, Seattle, Washington 98195, USA.
| | | | | |
Collapse
|
38
|
Mauban JRH, O'Donnell M, Warrier S, Manni S, Bond M. AKAP-scaffolding proteins and regulation of cardiac physiology. Physiology (Bethesda) 2009; 24:78-87. [PMID: 19364910 DOI: 10.1152/physiol.00041.2008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A kinase anchoring proteins (AKAPs) compose a growing list of diverse but functionally related proteins defined by their ability to bind to the regulatory subunit of protein kinase A. AKAPs perform an integral role in the spatiotemporal modulation of a multitude of cellular signaling pathways. This review highlights the extensive role of AKAPs in cardiac excitation/contraction coupling and cardiac physiology. The literature shows that particular AKAPs are involved in cardiac Ca(2+) influx, release, reuptake, and myocyte repolarization. Studies have also suggested roles for AKAPs in cardiac remodeling. Transgenic studies show functional effects of AKAPs, not only in the cardiovascular system but in other organ systems as well.
Collapse
Affiliation(s)
- J R H Mauban
- Departments of Physiology, University of Maryland Baltimore, Baltimore, Maryland, USA
| | | | | | | | | |
Collapse
|
39
|
Remme CA, Scicluna BP, Verkerk AO, Amin AS, van Brunschot S, Beekman L, Deneer VHM, Chevalier C, Oyama F, Miyazaki H, Nukina N, Wilders R, Escande D, Houlgatte R, Wilde AAM, Tan HL, Veldkamp MW, de Bakker JMT, Bezzina CR. Genetically determined differences in sodium current characteristics modulate conduction disease severity in mice with cardiac sodium channelopathy. Circ Res 2009; 104:1283-92. [PMID: 19407241 DOI: 10.1161/circresaha.109.194423] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Conduction slowing of the electric impulse that drives the heartbeat may evoke lethal cardiac arrhythmias. Mutations in SCN5A, which encodes the pore-forming cardiac sodium channel alpha subunit, are associated with familial arrhythmia syndromes based on conduction slowing. However, disease severity among mutation carriers is highly variable. We hypothesized that genetic modifiers underlie the variability in conduction slowing and disease severity. With the aim of identifying such modifiers, we studied the Scn5a(1798insD/+) mutation in 2 distinct mouse strains, FVB/N and 129P2. In 129P2 mice, the mutation resulted in more severe conduction slowing particularly in the right ventricle (RV) compared to FVB/N. Pan-genomic mRNA expression profiling in the 2 mouse strains uncovered a drastic reduction in mRNA encoding the sodium channel auxiliary subunit beta4 (Scn4b) in 129P2 mice compared to FVB/N. This corresponded to low to undetectable beta4 protein levels in 129P2 ventricular tissue, whereas abundant beta4 protein was detected in FVB/N. Sodium current measurements in isolated myocytes from the 2 mouse strains indicated that sodium channel activation in myocytes from 129P2 mice occurred at more positive potentials compared to FVB/N. Using computer simulations, this difference in activation kinetics was predicted to explain the observed differences in conduction disease severity between the 2 strains. In conclusion, genetically determined differences in sodium current characteristics on the myocyte level modulate disease severity in cardiac sodium channelopathies. In particular, the sodium channel subunit beta4 (SCN4B) may constitute a potential genetic modifier of conduction and cardiac sodium channel disease.
Collapse
Affiliation(s)
- Carol Ann Remme
- Heart Failure Research Center, Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Room K2-110, PO Box 22700, 1100 DE Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Costa-Junior HM, Suetsugu MJ, Krieger JE, Schechtman D. Specific modulation of protein kinase activity via small peptides. ACTA ACUST UNITED AC 2009; 153:11-8. [DOI: 10.1016/j.regpep.2008.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 12/01/2008] [Accepted: 12/06/2008] [Indexed: 11/15/2022]
|
41
|
Entropic contributions and the influence of the hydrophobic environment in promiscuous protein-protein association. Proc Natl Acad Sci U S A 2008; 105:7456-61. [PMID: 18495919 DOI: 10.1073/pnas.0800452105] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanisms by which a promiscuous protein can strongly interact with several different proteins using the same binding interface are not completely understood. An example is protein kinase A (PKA), which uses a single face on its docking/dimerization domain to interact with multiple A-kinase anchoring proteins (AKAP) that localize it to different parts of the cell. In the current study, the configurational entropy contributions to the binding between the AKAP protein HT31 with the D/D domain of RII alpha-regulatory subunit of PKA were examined. The results show that the majority of configurational entropy loss for the interaction was due to decreased fluctuations within rotamer states of the side chains. The result is in contrast to the widely held approximation that the decrease in the number of rotamer states available to the side chains forms the major component. Further analysis showed that there was a direct linear relationship between total configurational entropy and the number of favorable, alternative contacts available within hydrophobic environments. The hydrophobic binding pocket of the D/D domain provides alternative contact points for the side chains of AKAP peptides that allow them to adopt different binding conformations. The increase in binding conformations provides an increase in binding entropy and hence binding affinity. We infer that a general strategy for a promiscuous protein is to provide alternative contact points at its interface to increase binding affinity while the plasticity required for binding to multiple partners is retained. Implications are discussed for understanding and treating diseases in which promiscuous protein interactions are used.
Collapse
|
42
|
Frank B, Wiestler M, Kropp S, Hemminki K, Spurdle AB, Sutter C, Wappenschmidt B, Chen X, Beesley J, Hopper JL, Meindl A, Kiechle M, Slanger T, Bugert P, Schmutzler RK, Bartram CR, Flesch-Janys D, Mutschelknauss E, Ashton K, Salazar R, Webb E, Hamann U, Brauch H, Justenhoven C, Ko YD, Brüning T, Silva IDS, Johnson N, Pharoah PPD, Dunning AM, Pooley KA, Chang-Claude J, Easton DF, Peto J, Houlston R, Chenevix-Trench G, Fletcher O, Burwinkel B. Association of a common AKAP9 variant with breast cancer risk: a collaborative analysis. J Natl Cancer Inst 2008; 100:437-42. [PMID: 18334708 DOI: 10.1093/jnci/djn037] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Data from several studies have suggested that polymorphisms in A-kinase anchoring proteins (AKAPs), which are key components of signal transduction, contribute to carcinogenesis. To evaluate the impact of AKAP variants on breast cancer risk, we genotyped six nonsynonymous single-nucleotide polymorphisms that were predicted to be deleterious and found two (M463I, 1389G>T and N2792S, 8375A>G) to be associated with an allele dose-dependent increase in risk of familial breast cancer in a German population. We extended the analysis of AKAP9 M463I, which is in strong linkage disequilibrium with AKAP9 N2792S, to 9523 breast cancer patients and 13770 healthy control subjects from seven independent European and Australian breast cancer studies. All statistical tests were two-sided. The collaborative analysis confirmed the association of M463I with increased breast cancer risk. Among all breast cancer patients, the combined adjusted odds ratio (OR) of breast cancer for individuals homozygous for the rare allele TT (frequency = 0.19) compared with GG homozygotes was 1.17 (95% confidence interval [CI] = 1.08 to 1.27, P = .0003), and the OR for TT homozygotes plus GT heterozygotes compared with GG homozygotes was 1.10 (95% CI = 1.04 to 1.17, P = .001). Among the combined subset of 2795 familial breast cancer patients, the respective ORs were 1.27 (95% CI = 1.12 to 1.45, P = .0003) and 1.16 (95% CI = 1.06 to 1.27, P = .001).
Collapse
Affiliation(s)
- Bernd Frank
- Helmholtz-University Group Molecular Epidemiology, Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Deshpande A, Wheeler C, Hunt W, Peyton C, White P, Valdez Y, Nolan J. Variation in HLA Class I Antigen‐Processing Genes and Susceptibility to Human Papillomavirus Type 16–Associated Cervical Cancer. J Infect Dis 2008; 197:371-81. [DOI: 10.1086/524300] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
44
|
Gorlov IP, Meyer P, Liloglou T, Myles J, Boettger MB, Cassidy A, Girard L, Minna JD, Fischer R, Duffy S, Spitz MR, Haeussinger K, Kammerer S, Cantor C, Dierkesmann R, Field JK, Amos CI. Seizure 6-Like (SEZ6L) Gene and Risk for Lung Cancer. Cancer Res 2007; 67:8406-11. [PMID: 17804757 DOI: 10.1158/0008-5472.can-06-4784] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DNA pooling in combination with high-throughput sequencing was done as a part of the Sequenom-Genefinder project. In the pilot study, we tested 83,715 single nucleotide polymorphisms (SNP), located primarily in gene-based regions, to identify polymorphic susceptibility variants for lung cancer. For this pilot study, 369 male cases and 287 controls of both sexes (white Europeans of Southern German origin) were analyzed. The study identified a candidate region in 22q12.2 that contained numerous SNPs showing significant case-control differences and that coincides with a region that was shown previously to be frequently deleted in lung cancer cell lines. The candidate region overlies the seizure 6-like (SEZ6L) gene. The pilot study identified a polymorphic Met430Ile substitution in the SEZ6L gene (SNP rs663048) as the top candidate for a variant modulating risk of lung cancer. Two replication studies were conducted to assess the association of SNP rs663048 with lung cancer risk. The M. D. Anderson Cancer Center study included 289 cases and 291 controls matched for gender, age, and smoking status. The Liverpool Lung Project (a United Kingdom study) included 248 cases and 233 controls. Both replication studies showed an association of the rs663048 with lung cancer risk. The homozygotes for the variant allele had more than a 3-fold risk compared with the wild-type homozygotes [combined odds ratio (OR), 3.32; 95% confidence interval (95% CI), 1.81-7.21]. Heterozygotes also had a significantly elevated risk of lung cancer from the combined replication studies with an OR of 1.15 (95% CI, 1.04-1.59). The effect remained significant after adjusting for age, gender, and pack-years of tobacco smoke. We also compared expression of SEZ6L in normal human bronchial epithelial cells (n = 7), non-small cell lung cancer (NSCLC; n = 52), and small cell lung cancer (SCLC; n = 22) cell lines by using Affymetrix HG-U133A and HG-U133B GeneChips. We found that the average expression level of SEZ6L in NSCLC cell lines was almost two times higher and in SCLC cell lines more than six times higher when compared with normal lung epithelial cell lines. Using the National Center for Biotechnology Information Gene Expression Omnibus database, we found a approximately 2-fold elevated and statistically significant (P = 0.004) level of SEZ6L expression in tumor samples compared with normal lung tissues. In conclusion, the results of these studies representing 906 cases compared with 811 controls indicate a role of the SEZ6L Met430Ile polymorphic variant in increasing lung cancer risk.
Collapse
Affiliation(s)
- Ivan P Gorlov
- Department of Epidemiology, The University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Tingley WG, Pawlikowska L, Zaroff JG, Kim T, Nguyen T, Young SG, Vranizan K, Kwok PY, Whooley MA, Conklin BR. Gene-trapped mouse embryonic stem cell-derived cardiac myocytes and human genetics implicate AKAP10 in heart rhythm regulation. Proc Natl Acad Sci U S A 2007; 104:8461-6. [PMID: 17485678 PMCID: PMC1866184 DOI: 10.1073/pnas.0610393104] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sudden cardiac death due to abnormal heart rhythm kills 400,000-460,000 Americans each year. To identify genes that regulate heart rhythm, we are developing a screen that uses mouse embryonic stem cells (mESCs) with gene disruptions that can be differentiated into cardiac cells for phenotyping. Here, we show that the heterozygous disruption of the Akap10 (D-AKAP2) gene that disrupts the final 51 aa increases the contractile response of cultured cardiac cells to cholinergic signals. In both heterozygous and homozygous mutant mice derived from these mESCs, the same Akap10 disruption increases the cardiac response to cholinergic signals, suggesting a dominant interfering effect of the Akap10 mutant allele. The mutant mice have cardiac arrhythmias and die prematurely. We also found that a common variant of AKAP10 in humans (646V, 40% of alleles) was associated with increased basal heart rate and decreased heart rate variability (markers of low cholinergic/vagus nerve sensitivity). These markers predict an increased risk of sudden cardiac death. Although the molecular mechanism remains unknown, our findings in mutant mESCs, mice, and a common human AKAP10 SNP all suggest a role for AKAP10 in heart rhythm control. Our stem cell-based screen may provide a means of identifying other genes that control heart rhythm.
Collapse
Affiliation(s)
- Whittemore G. Tingley
- *Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
- Departments of Medicine and
| | | | | | - Taeryn Kim
- *Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Trieu Nguyen
- *Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
| | - Stephen G. Young
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Karen Vranizan
- *Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
- Functional Genomics Laboratory, University of California, Berkeley, CA 94720; and
| | | | - Mary A. Whooley
- Departments of Medicine and
- **Veterans Affairs Medical Center, San Francisco, CA 94143
| | - Bruce R. Conklin
- *Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
- Departments of Medicine and
- Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94143
- To whom correspondence should be addressed at:
Gladstone Institute of Cardiovascular Disease, 1650 Owens Street, San Francisco, CA 94158. E-mail:
| |
Collapse
|
46
|
Lim CJ, Han J, Yousefi N, Ma Y, Amieux PS, McKnight GS, Taylor SS, Ginsberg MH. Alpha4 integrins are type I cAMP-dependent protein kinase-anchoring proteins. Nat Cell Biol 2007; 9:415-21. [PMID: 17369818 DOI: 10.1038/ncb1561] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2007] [Accepted: 02/23/2007] [Indexed: 11/08/2022]
Abstract
A-kinase anchoring proteins (AKAPs) control the localization and substrate specificity of cAMP-dependent protein kinase (PKA), tetramers of regulatory (PKA-R) and catalytic (PKA-C) subunits, by binding to PKA-R subunits. Most mammalian AKAPs bind Type II PKA through PKA-RII (ref. 2), whereas dual specificity AKAPs bind both PKA-RI and PKA-RII (ref. 3). Inhibition of PKA-AKAP interactions modulates PKA signalling. Localized PKA activation in pseudopodia of migrating cells phosphorylates alpha4 integrins to provide spatial cues governing cell motility. Here, we report that the alpha4 cytoplasmic domain is a Type I PKA-specific AKAP that is distinct from canonical AKAPs in two ways: the alpha4 interaction requires the PKA holoenzyme, and is insensitive to amphipathic peptides that disrupt most PKA-AKAP interactions. We exploited type-specific PKA anchoring peptides to create genetically encoded baits that sequester specific PKA isoforms to the mitochondria and found that mislocalization of Type I, but not Type II, PKA disrupts alpha4 phosphorylation and markedly inhibits the velocity and directional persistence of cell migration.
Collapse
Affiliation(s)
- Chinten James Lim
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Pearson JV, Huentelman MJ, Halperin RF, Tembe WD, Melquist S, Homer N, Brun M, Szelinger S, Coon KD, Zismann VL, Webster JA, Beach T, Sando SB, Aasly JO, Heun R, Jessen F, Kolsch H, Tsolaki M, Daniilidou M, Reiman EM, Papassotiropoulos A, Hutton ML, Stephan DA, Craig DW. Identification of the genetic basis for complex disorders by use of pooling-based genomewide single-nucleotide-polymorphism association studies. Am J Hum Genet 2007; 80:126-39. [PMID: 17160900 PMCID: PMC1785308 DOI: 10.1086/510686] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2006] [Accepted: 11/07/2006] [Indexed: 01/06/2023] Open
Abstract
We report the development and validation of experimental methods, study designs, and analysis software for pooling-based genomewide association (GWA) studies that use high-throughput single-nucleotide-polymorphism (SNP) genotyping microarrays. We first describe a theoretical framework for establishing the effectiveness of pooling genomic DNA as a low-cost alternative to individually genotyping thousands of samples on high-density SNP microarrays. Next, we describe software called "GenePool," which directly analyzes SNP microarray probe intensity data and ranks SNPs by increased likelihood of being genetically associated with a trait or disorder. Finally, we apply these methods to experimental case-control data and demonstrate successful identification of published genetic susceptibility loci for a rare monogenic disease (sudden infant death with dysgenesis of the testes syndrome), a rare complex disease (progressive supranuclear palsy), and a common complex disease (Alzheimer disease) across multiple SNP genotyping platforms. On the basis of these theoretical calculations and their experimental validation, our results suggest that pooling-based GWA studies are a logical first step for determining whether major genetic associations exist in diseases with high heritability.
Collapse
Affiliation(s)
- John V Pearson
- Translational Genomics Research Institute, Phoenix, AZ, 85004, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Abstract
The use of genomic technologies in biogerontology has the potential to greatly enhance our understanding of human ageing. High-throughput screens for alleles correlated with survival in long-lived people have uncovered novel genes involved in age-associated disease. Genome-wide longevity studies in simple eukaryotes are identifying evolutionarily conserved pathways that determine longevity. It is hoped that validation of these 'public' aspects of ageing in mice, along with analyses of variation in candidate human ageing genes, will provide targets for future interventions to slow the ageing process and retard the onset of age-associated pathologies.
Collapse
Affiliation(s)
- Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98195, USA.
| |
Collapse
|
49
|
Kinderman FS, Kim C, von Daake S, Ma Y, Pham BQ, Spraggon G, Xuong NH, Jennings PA, Taylor SS. A dynamic mechanism for AKAP binding to RII isoforms of cAMP-dependent protein kinase. Mol Cell 2006; 24:397-408. [PMID: 17081990 PMCID: PMC1855097 DOI: 10.1016/j.molcel.2006.09.015] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 08/09/2006] [Accepted: 09/25/2006] [Indexed: 11/28/2022]
Abstract
A kinase-anchoring proteins (AKAPs) target PKA to specific microdomains by using an amphipathic helix that docks to N-terminal dimerization and docking (D/D) domains of PKA regulatory (R) subunits. To understand specificity, we solved the crystal structure of the helical motif from D-AKAP2, a dual-specific AKAP, bound to the RIIalpha D/D domain. The 1.6 Angstrom structure reveals how this dynamic, hydrophobic docking site is assembled. A stable, hydrophobic docking groove is formed by the helical interface of two RIIalpha protomers. The flexible N terminus of one protomer is then recruited to the site, anchored to the peptide through two essential isoleucines. The other N terminus is disordered. This asymmetry provides greater possibilities for AKAP docking. Although there is strong discrimination against RIalpha in the N terminus of the AKAP helix, the hydrophobic groove discriminates against RIIalpha. RIalpha, with a cavity in the groove, can accept a bulky tryptophan, whereas RIIalpha requires valine.
Collapse
Affiliation(s)
- Francis S. Kinderman
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
- Department of Pharmacology, University of California, San Diego, CA 92093, USA
| | - Choel Kim
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
| | - Sventja von Daake
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
| | - Yuliang Ma
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
- Howard Hughes Medical Institute, University of California, San Diego, CA 92093, USA
| | - Bao Q. Pham
- Division of Biological Sciences, University of California, San Diego, CA 92093, USA
| | - Glen Spraggon
- The Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
| | - Nguyen-Huu Xuong
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
- Department of Physics, University of California, San Diego, CA 92093, USA
| | - Patricia A. Jennings
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
| | - Susan S. Taylor
- Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093, USA
- Department of Pharmacology, University of California, San Diego, CA 92093, USA
- Howard Hughes Medical Institute, University of California, San Diego, CA 92093, USA
- Correspondence Susan S. Taylor, Phone: (858) 534-3677, Fax: (858) 534-8193,
| |
Collapse
|
50
|
Gold MG, Lygren B, Dokurno P, Hoshi N, McConnachie G, Taskén K, Carlson CR, Scott JD, Barford D. Molecular Basis of AKAP Specificity for PKA Regulatory Subunits. Mol Cell 2006; 24:383-95. [PMID: 17081989 DOI: 10.1016/j.molcel.2006.09.006] [Citation(s) in RCA: 221] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 07/28/2006] [Accepted: 09/14/2006] [Indexed: 01/20/2023]
Abstract
Localization of cyclic AMP (cAMP)-dependent protein kinase (PKA) by A kinase-anchoring proteins (AKAPs) restricts the action of this broad specificity kinase. The high-resolution crystal structures of the docking and dimerization (D/D) domain of the RIIalpha regulatory subunit of PKA both in the apo state and in complex with the high-affinity anchoring peptide AKAP-IS explain the molecular basis for AKAP-regulatory subunit recognition. AKAP-IS folds into an amphipathic alpha helix that engages an essentially preformed shallow groove on the surface of the RII dimer D/D domains. Conserved AKAP aliphatic residues dominate interactions to RII at the predominantly hydrophobic interface, whereas polar residues are important in conferring R subunit isoform specificity. Using a peptide screening approach, we have developed SuperAKAP-IS, a peptide that is 10,000-fold more selective for the RII isoform relative to RI and can be used to assess the impact of PKA isoform-selective anchoring on cAMP-responsive events inside cells.
Collapse
Affiliation(s)
- Matthew G Gold
- Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, United Kingdom
| | | | | | | | | | | | | | | | | |
Collapse
|