1
|
Grochowska KM, Sperveslage M, Raman R, Failla AV, Głów D, Schulze C, Laprell L, Fehse B, Kreutz MR. Chaperone-mediated autophagy in neuronal dendrites utilizes activity-dependent lysosomal exocytosis for protein disposal. Cell Rep 2023; 42:112998. [PMID: 37590146 DOI: 10.1016/j.celrep.2023.112998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 06/16/2023] [Accepted: 08/01/2023] [Indexed: 08/19/2023] Open
Abstract
The complex morphology of neurons poses a challenge for proteostasis because the majority of lysosomal degradation machinery is present in the cell soma. In recent years, however, mature lysosomes were identified in dendrites, and a fraction of those appear to fuse with the plasma membrane and release their content to the extracellular space. Here, we report that dendritic lysosomes are heterogeneous in their composition and that only those containing lysosome-associated membrane protein (LAMP) 2A and 2B fuse with the membrane and exhibit activity-dependent motility. Exocytotic lysosomes dock in close proximity to GluN2B-containing N-methyl-D-aspartate-receptors (NMDAR) via an association of LAMP2B to the membrane-associated guanylate kinase family member SAP102/Dlg3. NMDAR-activation decreases lysosome motility and promotes membrane fusion. We find that chaperone-mediated autophagy is a supplier of content that is released to the extracellular space via lysosome exocytosis. This mechanism enables local disposal of aggregation-prone proteins like TDP-43 and huntingtin.
Collapse
Affiliation(s)
- Katarzyna M Grochowska
- Leibniz Group "Dendritic Organelles and Synaptic Function," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.
| | - Marit Sperveslage
- Leibniz Group "Dendritic Organelles and Synaptic Function," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Rajeev Raman
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Antonio V Failla
- UKE Microscopic Imaging Facility (umif), University Medical Center Eppendorf, 20251 Hamburg, Germany
| | - Dawid Głów
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Centre Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Christian Schulze
- Institute of Synaptic Physiology, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Laura Laprell
- Institute of Synaptic Physiology, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Boris Fehse
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Centre Hamburg-Eppendorf (UKE), 20246 Hamburg, Germany
| | - Michael R Kreutz
- Leibniz Group "Dendritic Organelles and Synaptic Function," Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany; Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto von Guericke University, 39120 Magdeburg, Germany; German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany.
| |
Collapse
|
2
|
Bahouth SW, Nooh MM, Mancarella S. Involvement of SAP97 anchored multiprotein complexes in regulating cardiorenal signaling and trafficking networks. Biochem Pharmacol 2023; 208:115406. [PMID: 36596415 DOI: 10.1016/j.bcp.2022.115406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023]
Abstract
SAP97 is a member of the MAGUK family of proteins, but unlike other MAGUK proteins that are selectively expressed in the CNS, SAP97 is also expressed in peripheral organs, like the heart and kidneys. SAP97 has several protein binding cassettes, and this review will describe their involvement in creating SAP97-anchored multiprotein networks. SAP97-anchored networks localized at the inner leaflet of the cell membrane play a major role in trafficking and targeting of membrane G protein-coupled receptors (GPCR), channels, and structural proteins. SAP97 plays a major role in compartmentalizing voltage gated sodium and potassium channels to specific cellular compartments of heart cells. SAP97 undergoes extensive alternative splicing. These splice variants give rise to different SAP97 isoforms that alter its cellular localization, networking, signaling and trafficking effects. Regarding GPCR, SAP97 binds to the β1-adrenergic receptor and recruits AKAP5/PKA and PDE4D8 to create a multiprotein complex that regulates trafficking and signaling of cardiac β1-AR. In the kidneys, SAP97 anchored networks played a role in trafficking of aquaporin-2 water channels. Cardiac specific ablation of SAP97 (SAP97-cKO) resulted in cardiac hypertrophy and failure in aging mice. Similarly, instituting transverse aortic constriction (TAC) in young SAP97 c-KO mice exacerbated TAC-induced cardiac remodeling and dysfunction. These findings highlight a critical role for SAP97 in the pathophysiology of a number of cardiac and renal diseases, suggesting that SAP97 is a relevant target for drug discovery.
Collapse
Affiliation(s)
- Suleiman W Bahouth
- Department of Pharmacology, Addiction Science and Toxicology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States.
| | - Mohammed M Nooh
- Department of Biochemistry, Faculty of Pharmacy Cairo University, Cairo, Egypt and Biochemistry Department, Faculty of Pharmacy, October 6 University, Giza, Egypt
| | - Salvatore Mancarella
- Department of Physiology, The University of Tennessee-Health Sciences Center, Memphis, TN, United States
| |
Collapse
|
3
|
Rajeev P, Singh N, Kechkar A, Butler C, Ramanan N, Sibarita JB, Jose M, Nair D. Nanoscale regulation of Ca2+ dependent phase transitions and real-time dynamics of SAP97/hDLG. Nat Commun 2022; 13:4236. [PMID: 35869063 PMCID: PMC9307800 DOI: 10.1038/s41467-022-31912-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 07/08/2022] [Indexed: 11/20/2022] Open
Abstract
Synapse associated protein-97/Human Disk Large (SAP97/hDLG) is a conserved, alternatively spliced, modular, scaffolding protein critical in regulating the molecular organization of cell-cell junctions in vertebrates. We confirm that the molecular determinants of first order phase transition of SAP97/hDLG is controlled by morpho-functional changes in its nanoscale organization. Furthermore, the nanoscale molecular signatures of these signalling islands and phase transitions are altered in response to changes in cytosolic Ca2+. Additionally, exchange kinetics of alternatively spliced isoforms of the intrinsically disordered region in SAP97/hDLG C-terminus shows differential sensitivities to Ca2+ bound Calmodulin, affirming that the molecular signatures of local phase transitions of SAP97/hDLG depends on their nanoscale heterogeneity and compositionality of isoforms. SAP97/hDLG is a ubiquitous, alternatively spliced, and conserved modular scaffolding protein involved in the organization cell junctions and excitatory synapses. Here, authors confirm that SAP97/hDLG condenses in to nanosized molecular domains in both heterologous cells and hippocampal pyramidal neurons. Authors demonstrate that in vivo and in vitro condensation, molecular signatures of nanoscale condensates and exchange kinetics of SAP97/hDLG is modulated by the local availability of alternatively spliced isoforms. Additionally, SAP97/hDLG isoforms exhibits a differential sensitivity to Ca2+ bound Calmodulin, resulting in altered properties of nanocondensates and their real-time regulation
Collapse
|
4
|
Gupta R. Self-crowding of AMPA receptors in the excitatory postsynaptic density can effectuate anomalous receptor sub-diffusion. PLoS Comput Biol 2018; 14:e1005984. [PMID: 29444074 PMCID: PMC5812565 DOI: 10.1371/journal.pcbi.1005984] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/15/2018] [Indexed: 12/03/2022] Open
Abstract
AMPA receptors (AMPARs) and their associations with auxiliary transmembrane proteins are bulky structures with large steric-exclusion volumes. Hence, self-crowding of AMPARs, depending on the local density, may affect their lateral diffusion in the postsynaptic membrane as well as in the highly crowded postsynaptic density (PSD) at excitatory synapses. Earlier theoretical studies considered only the roles of transmembrane obstacles and the AMPAR-binding submembranous scaffold proteins in shaping receptor diffusion within PSD. Using lattice model of diffusion, the present study investigates the additional impacts of self-crowding on the anomalousity and effective diffusion coefficient (Deff) of AMPAR diffusion. A recursive algorithm for avoiding false self-blocking during diffusion simulation is also proposed. The findings suggest that high density of AMPARs in the obstacle-free membrane itself engenders strongly anomalous diffusion and severe decline in Deff. Adding transmembrane obstacles to the membrane accentuates the anomalousity arising from self-crowding due to the reduced free diffusion space. Contrarily, enhanced AMPAR-scaffold binding, either through increase in binding strength or scaffold density or both, ameliorates the anomalousity resulting from self-crowding. However, binding has differential impacts on Deff depending on the receptor density. Increase in binding causes consistent decrease in Deff for low and moderate receptor density. For high density, binding increases Deff as long as it reduces anomalousity associated with intense self-crowding. Given a sufficiently strong binding condition when diffusion acquires normal behavior, further increase in binding causes decrease in Deff. Supporting earlier experimental observations are mentioned and implications of present findings to the experimental observations on AMPAR diffusion are also drawn. The transmembrane AMPA receptors (AMPARs) prominently exhibit lateral diffusion in the postsynaptic membrane at excitatory synapses. Steric obstructions to AMPAR diffusion due to the crowd of other relatively static transmembrane proteins and binding of AMPARs to the submembranous scaffold proteins in the specialized region of postsynaptic density (PSD) are well known to retard receptor diffusion, which causes receptor trapping and accumulation within PSD. However, AMPARs are significantly bulky structures and may also obstruct their own diffusion paths in the presence of their high density. It is shown here that intense self-crowding of AMPARs may lead to highly obstructed and confined receptor diffusion even in the obstacle-free medium, and the presence of other obstacles further aggravates this effect. AMPAR-scaffold binding reduces confined diffusion arising from self-crowding and strong binding engenders normal diffusion even at high receptor density. However, it overall causes reduction in the effective diffusion coefficient of the receptor diffusion.
Collapse
Affiliation(s)
- Rahul Gupta
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
| |
Collapse
|
5
|
Chowdhury D, Turner M, Patriarchi T, Hergarden AC, Anderson D, Zhang Y, Sun J, Chen CY, Ames JB, Hell JW. Ca 2+/calmodulin binding to PSD-95 mediates homeostatic synaptic scaling down. EMBO J 2017; 37:122-138. [PMID: 29118000 DOI: 10.15252/embj.201695829] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 09/07/2017] [Accepted: 10/02/2017] [Indexed: 11/09/2022] Open
Abstract
Postsynaptic density protein-95 (PSD-95) localizes AMPA-type glutamate receptors (AMPARs) to postsynaptic sites of glutamatergic synapses. Its postsynaptic displacement is necessary for loss of AMPARs during homeostatic scaling down of synapses. Here, we demonstrate that upon Ca2+ influx, Ca2+/calmodulin (Ca2+/CaM) binding to the N-terminus of PSD-95 mediates postsynaptic loss of PSD-95 and AMPARs during homeostatic scaling down. Our NMR structural analysis identified E17 within the PSD-95 N-terminus as important for binding to Ca2+/CaM by interacting with R126 on CaM. Mutating E17 to R prevented homeostatic scaling down in primary hippocampal neurons, which is rescued via charge inversion by ectopic expression of CaMR126E, as determined by analysis of miniature excitatory postsynaptic currents. Accordingly, increased binding of Ca2+/CaM to PSD-95 induced by a chronic increase in Ca2+ influx is a critical molecular event in homeostatic downscaling of glutamatergic synaptic transmission.
Collapse
Affiliation(s)
| | - Matthew Turner
- Department of Chemistry, University of California, Davis, CA, USA
| | | | - Anne C Hergarden
- Department of Pharmacology, University of California, Davis, CA, USA
| | - David Anderson
- Department of Chemistry, University of California, Davis, CA, USA
| | - Yonghong Zhang
- Department of Chemistry, University of Texas, Edinburgh, TX, USA
| | - Junqing Sun
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
| |
Collapse
|
6
|
de Siqueira RJB, Ribeiro-Filho HV, Freire RS, Cosker F, Freire WBS, Vasconcelos-Silva AA, Soares MA, Lahlou S, Magalhães PJC. (-)-α-Bisabolol inhibits preferentially electromechanical coupling on rat isolated arteries. Vascul Pharmacol 2014; 63:37-45. [PMID: 25128618 DOI: 10.1016/j.vph.2014.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/09/2014] [Accepted: 06/26/2014] [Indexed: 01/23/2023]
Abstract
Previous findings enable us to hypothesize that (-)-α-bisabolol acts as inhibitor of voltage-dependent Ca(2+) channels in smooth muscle. The current study was aimed at consolidating such hypothesis through the recording of isometric tension, measurement of intracellular Ca(2+) as well as discovery of channel target using in silico analysis. In rat aortic rings, (-)-α-bisabolol (1-1000 µM) relaxed KCl- and phenylephrine-elicited contractions, but the IC50 differed significantly (22.8 [17.6-27.7] and 200.7 [120.4-334.6] µM, respectively). The relaxation of phenylephrine contractions remained unaffected by l-NAME, indomethacin, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, tetraethylammonium, glibenclamide or KT-5720. Under Ca(2+)-free conditions, (-)-α-bisabolol did not alter the contractions evoked by phenylephrine or caffeine whereas it reduced those evoked by CaCl2 in KCl-, but not in PHE-stimulated preparations. Furthermore, it did not significantly alter the contractions evoked by phorbol 12,13-dibutyrate or induced by the extracellular Ca(2+) restoration in cyclopiazonic acid-treated preparations. In mesenteric rings loaded with Fluo-4 AM, (-)-α-bisabolol blunted the tension and the cytosolic levels of Ca(2+) in response to K(+) but not to norepinephrine. Silico docking analysis of the Cavβ2a subunit of voltage-dependent Ca(2+) channel indicated putative docking sites for (-)-α-bisabolol. These findings reinforce the ability of (-)-α-bisabolol to inhibit preferentially contractile responses evoked by Ca(2+) influx through voltage-dependent Ca(2+) channels.
Collapse
Affiliation(s)
- R J B de Siqueira
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
| | - H V Ribeiro-Filho
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - R S Freire
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - F Cosker
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - W B S Freire
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - A A Vasconcelos-Silva
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - M A Soares
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - S Lahlou
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - P J C Magalhães
- Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| |
Collapse
|
7
|
Zhang Y, Matt L, Patriarchi T, Malik ZA, Chowdhury D, Park DK, Renieri A, Ames JB, Hell JW. Capping of the N-terminus of PSD-95 by calmodulin triggers its postsynaptic release. EMBO J 2014; 33:1341-53. [PMID: 24705785 DOI: 10.1002/embj.201488126] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Postsynaptic density protein-95 (PSD-95) is a central element of the postsynaptic architecture of glutamatergic synapses. PSD-95 mediates postsynaptic localization of AMPA receptors and NMDA receptors and plays an important role in synaptic plasticity. PSD-95 is released from postsynaptic membranes in response to Ca(2+) influx via NMDA receptors. Here, we show that Ca(2+)/calmodulin (CaM) binds at the N-terminus of PSD-95. Our NMR structure reveals that both lobes of CaM collapse onto a helical structure of PSD-95 formed at its N-terminus (residues 1-16). This N-terminal capping of PSD-95 by CaM blocks palmitoylation of C3 and C5, which is required for postsynaptic PSD-95 targeting and the binding of CDKL5, a kinase important for synapse stability. CaM forms extensive hydrophobic contacts with Y12 of PSD-95. The PSD-95 mutant Y12E strongly impairs binding to CaM and Ca(2+)-induced release of PSD-95 from the postsynaptic membrane in dendritic spines. Our data indicate that CaM binding to PSD-95 serves to block palmitoylation of PSD-95, which in turn promotes Ca(2+)-induced dissociation of PSD-95 from the postsynaptic membrane.
Collapse
Affiliation(s)
- Yonghong Zhang
- Department of Chemistry, University of California, Davis, CA, USA
| | - Lucas Matt
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, CA, USA Department of Medical Genetics, University of Siena, Siena, Italy
| | - Zulfiqar A Malik
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Deborah K Park
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
| |
Collapse
|
8
|
Fertuzinhos S, Li M, Kawasawa YI, Ivic V, Franjic D, Singh D, Crair M, Sestan N. Laminar and temporal expression dynamics of coding and noncoding RNAs in the mouse neocortex. Cell Rep 2014; 6:938-50. [PMID: 24561256 DOI: 10.1016/j.celrep.2014.01.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/10/2013] [Accepted: 01/27/2014] [Indexed: 12/30/2022] Open
Abstract
The hallmark of the cerebral neocortex is its organization into six layers, each containing a characteristic set of cell types and synaptic connections. The transcriptional events involved in laminar development and function still remain elusive. Here, we employed deep sequencing of mRNA and small RNA species to gain insights into transcriptional differences among layers and their temporal dynamics during postnatal development of the mouse primary somatosensory neocortex. We identify a number of coding and noncoding transcripts with specific spatiotemporal expression and splicing patterns. We also identify signature trajectories and gene coexpression networks associated with distinct biological processes and transcriptional overlap between these processes. Finally, we provide data that allow the study of potential miRNA and mRNA interactions. Overall, this study provides an integrated view of the laminar and temporal expression dynamics of coding and noncoding transcripts in the mouse neocortex and a resource for studies of neurodevelopment and transcriptome.
Collapse
Affiliation(s)
- Sofia Fertuzinhos
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Mingfeng Li
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Yuka Imamura Kawasawa
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA; Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Vedrana Ivic
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Daniel Franjic
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Darshani Singh
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Michael Crair
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA; Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA
| | - Nenad Sestan
- Department of Neurobiology, Yale School of Medicine, New Haven, CT 06510, USA; Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, USA.
| |
Collapse
|
9
|
Mori S, Tezuka Y, Arakawa A, Handa N, Shirouzu M, Akiyama T, Yokoyama S. Crystal structure of the guanylate kinase domain from discs large homolog 1 (DLG1/SAP97). Biochem Biophys Res Commun 2013; 435:334-8. [PMID: 23624197 DOI: 10.1016/j.bbrc.2013.04.056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 04/16/2013] [Indexed: 12/01/2022]
Abstract
Discs large homolog 1 (DLG1/SAP97) is involved in the development and regulation of neuronal and immunological synapses. DLG1 is a member of the membrane associated guanylate kinase (MAGUK) family of proteins, which function as molecular scaffolds. The C-terminal guanylate kinase (GK) domain of DLG1 binds peptides with a phosphorylated serine residue. In this study, we solved the crystal structure of the GK domain of human DLG1. The C-terminal tail of DLG1 is bound to the peptide-binding site of an adjacent symmetry-related DLG1 GK molecule. The binding direction of the C-terminal tail to the peptide-binding site is opposite to that of the phosphorylated LGN peptide in complex with the rat DLG1 GK domain. The C-terminal tail forms a 310 helix, which is also different from the conformation of the phosphorylated LGN peptide. Nevertheless, the side chain interactions of the C-terminal tail with the DLG1 GK domain are similar to those of the phosphorylated LGN peptide.
Collapse
Affiliation(s)
- Shinji Mori
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | | | | | | | | | | | | |
Collapse
|
10
|
Krishna Subbaiah V, Massimi P, Boon SS, Myers MP, Sharek L, Garcia-Mata R, Banks L. The invasive capacity of HPV transformed cells requires the hDlg-dependent enhancement of SGEF/RhoG activity. PLoS Pathog 2012; 8:e1002543. [PMID: 22383878 PMCID: PMC3285591 DOI: 10.1371/journal.ppat.1002543] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 01/06/2012] [Indexed: 11/19/2022] Open
Abstract
A major target of the HPV E6 oncoprotein is the human Discs Large (hDlg) tumour suppressor, although how this interaction contributes to HPV-induced malignancy is still unclear. Using a proteomic approach we show that a strong interacting partner of hDlg is the RhoG-specific guanine nucleotide exchange factor SGEF. The interaction between hDlg1 and SGEF involves both PDZ and SH3 domain recognition, and directly contributes to the regulation of SGEF's cellular localization and activity. Consistent with this, hDlg is a strong enhancer of RhoG activity, which occurs in an SGEF-dependent manner. We also show that HPV-18 E6 can interact indirectly with SGEF in a manner that is dependent upon the presence of hDlg and PDZ binding capacity. In HPV transformed cells, E6 maintains a high level of RhoG activity, and this is dependent upon the presence of hDlg and SGEF, which are found in complex with E6. Furthermore, we show that E6, hDlg and SGEF each directly contributes to the invasive capacity of HPV-16 and HPV-18 transformed tumour cells. These studies demonstrate that hDlg has a distinct oncogenic function in the context of HPV induced malignancy, one of the outcomes of which is increased RhoG activity and increased invasive capacity.
Collapse
Affiliation(s)
| | - Paola Massimi
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Siaw Shi Boon
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Michael P. Myers
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Lisa Sharek
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Rafael Garcia-Mata
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Lawrence Banks
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
- * E-mail:
| |
Collapse
|
11
|
Miranda-Laferte E, Gonzalez-Gutierrez G, Schmidt S, Zeug A, Ponimaskin EG, Neely A, Hidalgo P. Homodimerization of the Src homology 3 domain of the calcium channel β-subunit drives dynamin-dependent endocytosis. J Biol Chem 2011; 286:22203-10. [PMID: 21502319 DOI: 10.1074/jbc.m110.201871] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Voltage-dependent calcium channels constitute the main entry pathway for calcium into excitable cells. They are heteromultimers formed by an α(1) pore-forming subunit (Ca(V)α(1)) and accessory subunits. To achieve a precise coordination of calcium signals, the expression and activity of these channels is tightly controlled. The accessory β-subunit (Ca(V)β), a membrane associated guanylate kinase containing one guanylate kinase (β-GK) and one Src homology 3 (β-SH3) domain, has antagonistic effects on calcium currents by regulating different aspects of channel function. Although β-GK binds to a conserved site within the α(1)-pore-forming subunit and facilitates channel opening, β-SH3 binds to dynamin and promotes endocytosis. Here, we investigated the molecular switch underlying the functional duality of this modular protein. We show that β-SH3 homodimerizes through a single disulfide bond. Substitution of the only cysteine residue abolishes dimerization and impairs internalization of L-type Ca(V)1.2 channels expressed in Xenopus oocytes while preserving dynamin binding. Covalent linkage of the β-SH3 dimerization-deficient mutant yields a concatamer that binds to dynamin and restores endocytosis. Moreover, using FRET analysis, we show in living cells that Ca(V)β form oligomers and that this interaction is reduced by Ca(V)α(1). Association of Ca(V)β with a polypeptide encoding the binding motif in Ca(V)α(1) inhibited endocytosis. Together, these findings reveal that β-SH3 dimerization is crucial for endocytosis and suggest that channel activation and internalization are two mutually exclusive functions of Ca(V)β. We propose that a change in the oligomeric state of Ca(V)β is the functional switch between channel activator and channel internalizer.
Collapse
Affiliation(s)
- Erick Miranda-Laferte
- Institut für Neurophysiologie, Medizinische Hochschule Hannover, 30625 Hannover, Germany
| | | | | | | | | | | | | |
Collapse
|
12
|
Santamaria F, Gonzalez J, Augustine GJ, Raghavachari S. Quantifying the effects of elastic collisions and non-covalent binding on glutamate receptor trafficking in the post-synaptic density. PLoS Comput Biol 2010; 6:e1000780. [PMID: 20485563 PMCID: PMC2869312 DOI: 10.1371/journal.pcbi.1000780] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 04/09/2010] [Indexed: 11/19/2022] Open
Abstract
One mechanism of information storage in neurons is believed to be determined by the strength of synaptic contacts. The strength of an excitatory synapse is partially due to the concentration of a particular type of ionotropic glutamate receptor (AMPAR) in the post-synaptic density (PSD). AMPAR concentration in the PSD has to be plastic, to allow the storage of new memories; but it also has to be stable to preserve important information. Although much is known about the molecular identity of synapses, the biophysical mechanisms by which AMPAR can enter, leave and remain in the synapse are unclear. We used Monte Carlo simulations to determine the influence of PSD structure and activity in maintaining homeostatic concentrations of AMPARs in the synapse. We found that, the high concentration and excluded volume caused by PSD molecules result in molecular crowding. Diffusion of AMPAR in the PSD under such conditions is anomalous. Anomalous diffusion of AMPAR results in retention of these receptors inside the PSD for periods ranging from minutes to several hours in the absence of strong binding of receptors to PSD molecules. Trapping of receptors in the PSD by crowding effects was very sensitive to the concentration of PSD molecules, showing a switch-like behavior for retention of receptors. Non-covalent binding of AMPAR to anchored PSD molecules allowed the synapse to become well-mixed, resulting in normal diffusion of AMPAR. Binding also allowed the exchange of receptors in and out of the PSD. We propose that molecular crowding is an important biophysical mechanism to maintain homeostatic synaptic concentrations of AMPARs in the PSD without the need of energetically expensive biochemical reactions. In this context, binding of AMPAR with PSD molecules could collaborate with crowding to maintain synaptic homeostasis but could also allow synaptic plasticity by increasing the exchange of these receptors with the surrounding extra-synaptic membrane. One of the most accepted theories of information storage in neurons is that it is partially localized in the strength of synaptic contacts. Evidence suggests that at the cellular level, in combination with other cellular mechanisms, this is implemented by increasing or decreasing the concentration of a particular type of membrane molecules. Two opposing mechanisms have to coexist in synapses to allow them to store information. On one hand, synapses have to be flexible, to allow the storage of new memories. On the other hand, synapses have to be stable to preserve previously learned information. Although much is known about the molecular identity of synapses, the biophysical mechanisms by which molecules can enter, leave and remain in the synapse are unclear. Our modeling work uses fundamental biophysical principles to quantify the effects of molecular collisions and biochemical reactions. Our results show that molecular collisions alone, between the diffusing proteins with anchored molecules in the synapse, can replicate known experimental results. Molecular collision in combination with biochemical binding can be fundamental biophysical principles used by synapses for the formation and preservation of memories.
Collapse
Affiliation(s)
- Fidel Santamaria
- Biology Department, The University of Texas at San Antonio, San Antonio, Texas, United States of America
- Neurosciences Institute, The University of Texas at San Antonio, San Antonio, Texas, United States of America
- * E-mail: (FS); (SR)
| | - Jossina Gonzalez
- Biology Department, The University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - George J. Augustine
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sridhar Raghavachari
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail: (FS); (SR)
| |
Collapse
|
13
|
Bartos JA, Ulrich JD, Li H, Beazely MA, Chen Y, MacDonald JF, Hell JW. Postsynaptic clustering and activation of Pyk2 by PSD-95. J Neurosci 2010; 30:449-63. [PMID: 20071509 PMCID: PMC2822408 DOI: 10.1523/jneurosci.4992-08.2010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Revised: 11/01/2009] [Accepted: 11/04/2009] [Indexed: 12/24/2022] Open
Abstract
The tyrosine kinase Pyk2 plays a unique role in intracellular signal transduction by linking Ca(2+) influx to tyrosine phosphorylation, but the molecular mechanism of Pyk2 activation is unknown. We report that Pyk2 oligomerization by antibodies in vitro or overexpression of PSD-95 in PC6-3 cells induces trans-autophosphorylation of Tyr402, the first step in Pyk2 activation. In neurons, Ca(2+) influx through NMDA-type glutamate receptors causes postsynaptic clustering and autophosphorylation of endogenous Pyk2 via Ca(2+)- and calmodulin-stimulated binding to PSD-95. Accordingly, Ca(2+) influx promotes oligomerization and thereby autoactivation of Pyk2 by stimulating its interaction with PSD-95. We show that this mechanism of Pyk2 activation is critical for long-term potentiation in the hippocampus CA1 region, which is thought to underlie learning and memory.
Collapse
Affiliation(s)
- Jason A. Bartos
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - Jason D. Ulrich
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - Hongbin Li
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | - Michael A. Beazely
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
| | - Yucui Chen
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
| | - John F. MacDonald
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada, and
- Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8, Canada
| | - Johannes W. Hell
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242-1109
- Department of Pharmacology, University of California, Davis, Davis, California 95616-8636
| |
Collapse
|
14
|
Structural differences between the SH3-HOOK-GuK domains of SAP90/PSD-95 and SAP97. Protein Expr Purif 2009; 68:201-7. [DOI: 10.1016/j.pep.2009.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2009] [Revised: 07/14/2009] [Accepted: 07/20/2009] [Indexed: 11/24/2022]
|
15
|
Newman RA, Prehoda KE. Intramolecular interactions between the SRC homology 3 and guanylate kinase domains of discs large regulate its function in asymmetric cell division. J Biol Chem 2009; 284:12924-32. [PMID: 19261607 DOI: 10.1074/jbc.m809304200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Membrane-associated guanylate kinases (MAGUKs) regulate the formation and function of molecular assemblies at specialized regions of the membrane. Allosteric regulation of an intramolecular interaction between the Src homology 3 (SH3) and guanylate kinase (GK) domains of MAGUKs is thought to play a central role in regulating MAGUK function. Here we show that a mutant of the Drosophila MAGUK Discs large (Dlg), dlg(sw), encodes a form of Dlg that disrupts the intramolecular association while leaving the SH3 and GK domains intact, providing an excellent model system to assess the role of the SH3-GK intramolecular interaction in MAGUK function. Analysis of asymmetric cell division of maternal-zygotic dlg(sw) embryonic neuroblasts demonstrates that the intramolecular interaction is not required for Dlg localization but is necessary for cell fate determinant segregation to the basal cortex and mitotic spindle alignment with the cortical polarity axis. These defects ultimately result in improper patterning of the embryonic central nervous system. Furthermore, we demonstrate that the sw mutation of Dlg results in unregulated complex assembly as assessed by GukHolder association with the SH3-GK versus PDZ-SH3-GK modules of Dlg(sw). From these studies, we conclude that allosteric regulation of the SH3-GK intramolecular interaction is required for regulation of MAGUK function in asymmetric cell division, possibly through regulation of complex assembly.
Collapse
Affiliation(s)
- Rhonda A Newman
- Department of Chemistry and Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | | |
Collapse
|
16
|
Paarmann I, Lye MF, Lavie A, Konrad M. Structural requirements for calmodulin binding to membrane-associated guanylate kinase homologs. Protein Sci 2008; 17:1946-54. [PMID: 18809851 DOI: 10.1110/ps.035550.108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Effector molecules such as calmodulin modulate the interactions of membrane-associated guanylate kinase homologs (MAGUKs) and other scaffolding proteins of the membrane cytoskeleton by binding to the Src homology 3 (SH3) domain, the guanylate kinase (GK) domain, or the connecting HOOK region of MAGUKs. Using surface plasmon resonance, we studied the interaction of members of all four MAGUK subfamilies--synapse-associated protein 97 (SAP97), calcium/calmodulin-dependent serine protein kinase (CASK), membrane palmitoylated protein 2 (MPP2), and zona occludens (ZO) 1--and calmodulin to determine interaction affinities and localize the binding site. The SH3-GK domains of the proteins and derivatives thereof were expressed in E. coli and purified. In all four proteins, high-affinity calmodulin binding was identified. CASK was shown to contain a Ca2+-dependent calmodulin binding site within the HOOK region, overlapping with a protein 4.1 binding site. In ZO1, a Ca2+-dependent calmodulin binding site was detected within the GK domain. The equilibrium dissociation constants for MAGUK-calmodulin interaction were found to range from 50 nM to 180 nM. Sequence analyses suggest that binding sites for calmodulin have evolved independently in at least three subfamilies. For ZO1, pulldown of GST-calmodulin was shown to occur in a calcium-dependent manner; moreover, molecular modeling and sequence analyses predict conserved basic residues to be exposed on one side of a helix. Thus, calmodulin binding appears to be a common feature of MAGUKs, and Ca2+-activated calmodulin may serve as a general regulator to affect the interactions of MAGUKs and various components of the cytoskeleton.
Collapse
Affiliation(s)
- Ingo Paarmann
- 1Max-Planck Institute for Biophysical Chemistry, D-37077 Göttingen, Germany.
| | | | | | | |
Collapse
|
17
|
Reissner KJ, Boyle HD, Ye X, Carew TJ. Aplysia synapse associated protein (APSAP): identification, characterization, and selective interactions with Shaker-type potassium channels. J Neurochem 2007; 105:1006-18. [PMID: 18182049 DOI: 10.1111/j.1471-4159.2007.05202.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The vertebrate post-synaptic density (PSD) is a region of high molecular complexity in which dynamic protein interactions modulate receptor localization and synaptic function. Members of the membrane-associated guanylate kinase (MAGUK) family of proteins represent a major structural and functional component of the vertebrate PSD. In order to investigate the expression and significance of orthologous PSD components associated with the Aplysia sensory neuron-motor neuron synapse, we have cloned an Aplysia Dlg-MAGUK protein, which we identify as Aplysia synapse associated protein (ApSAP). As revealed by western blot, RT-PCR, and immunocytochemical analyses, ApSAP is predominantly expressed in the CNS and is located in both sensory neuron and motor neurons. The overall amino acid sequence of ApSAP is 55-61% identical to Drosophila Dlg and mammalian Dlg-MAGUK proteins, but is more highly conserved within L27, PDZ, SH3, and guanylate kinase domains. Because these conserved domains mediate salient interactions with receptors and other PSD components of the vertebrate synapse, we performed a series of GST pull-down assays using recombinant C-terminal tail proteins from various Aplysia receptors and channels containing C-terminal PDZ binding sequences. We have found that ApSAP selectively binds to an Aplysia Shaker-type channel AKv1.1, but not to (i) NMDA receptor subunit AcNR1-1, (ii) potassium channel AKv5.1, (iii) receptor tyrosine kinase ApTrkl, (iv) glutamate receptor ApGluR1/4, (v) glutamate receptor ApGluR2/3, or (vi) glutamate receptor ApGluR7. These findings provide preliminary information regarding the expression and interactions of Dlg-MAGUK proteins of the Aplysia CNS, and will inform questions aimed at a functional analysis of how interactions in a protein network such as the PSD may regulate synaptic strength.
Collapse
Affiliation(s)
- Kathryn J Reissner
- Department of Neurobiology and Behavior, University of California, Irvine, California, USA
| | | | | | | |
Collapse
|
18
|
Chang CW, Peng SC, Cheng WY, Liu SH, Cheng HH, Huang SY, Chang YC. Studying the protein–protein interactions in the postsynaptic density by means of immunoabsorption and chemical crosslinking. Proteomics Clin Appl 2007; 1:1499-512. [DOI: 10.1002/prca.200700327] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Indexed: 11/09/2022]
|
19
|
Reese ML, Dakoji S, Bredt DS, Dötsch V. The guanylate kinase domain of the MAGUK PSD-95 binds dynamically to a conserved motif in MAP1a. Nat Struct Mol Biol 2007; 14:155-63. [PMID: 17220895 DOI: 10.1038/nsmb1195] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Accepted: 12/27/2006] [Indexed: 11/08/2022]
Abstract
The postsynaptic density protein PSD-95 and related membrane-associated guanylate kinases are scaffolding proteins, whose modular interaction motifs organize protein complexes at cell junctions. The signature guanylate kinase domain (GK) contains elements of the protein's GMP-binding site but does not bind nucleotide. Instead, the GK domain has evolved from an enzyme to a protein-protein interaction motif. Here, we show that this canonical GMP-binding region interacts with microtubule-associated protein-1a (MAP1a) and we present a structural model. We determine the consensus GK-binding sequence in MAP1a and demonstrate that PSD-95 can use a similar interaction mode to bind diverse protein partners. Furthermore, we show that PSD-95 GK has adopted the conformational flexibility of the ancestral enzyme to bind its varied ligands, which suggests a mechanism of regulation.
Collapse
Affiliation(s)
- Michael L Reese
- Graduate Group in Biophysics, University of California, San Francisco, California 94143, USA
| | | | | | | |
Collapse
|
20
|
Fukunaga Y, Matsubara M, Nagai R, Miyazawa A. The interaction between PSD-95 and Ca2+/calmodulin is enhanced by PDZ-binding proteins. J Biochem 2005; 138:177-82. [PMID: 16091592 DOI: 10.1093/jb/mvi107] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In this study, we evaluate the interaction between the postsynaptic scaffolding protein, PSD-95, and calmodulin. Surface plasmon resonance spectroscopy was used to characterize the binding of PSD-95 to calmodulin that had been immobilized on a sensor chip. Additionally, soluble calmodulin was found to inhibit the binding of PSD-95 to immobilized calmodulin. The HOOK region of PSD-95, which is located between the src homology 3 domain and the guanylate kinase-like domain, was determined to be involved in the binding of PSD-95 to calmodulin. We also found that C-terminal peptides from proteins such as CRIPT and the N-methyl-d-aspartate receptor NR2B subunit, which associate with the PDZ domain of PSD-95, enhanced the affinity of PSD-95 for calmodulin. The binding of ligands to the PDZ domain may change the conformation of PSD-95 and affect the interaction between PSD-95 and calmodulin.
Collapse
Affiliation(s)
- Yuko Fukunaga
- Membrane Dynamics Project, RIKEN Harima Institute, Mikazuki, Sayo, Hyogo
| | | | | | | |
Collapse
|
21
|
Palmer CL, Cotton L, Henley JM. The molecular pharmacology and cell biology of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Pharmacol Rev 2005; 57:253-77. [PMID: 15914469 PMCID: PMC3314513 DOI: 10.1124/pr.57.2.7] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) are of fundamental importance in the brain. They are responsible for the majority of fast excitatory synaptic transmission, and their overactivation is potently excitotoxic. Recent findings have implicated AMPARs in synapse formation and stabilization, and regulation of functional AMPARs is the principal mechanism underlying synaptic plasticity. Changes in AMPAR activity have been described in the pathology of numerous diseases, such as Alzheimer's disease, stroke, and epilepsy. Unsurprisingly, the developmental and activity-dependent changes in the functional synaptic expression of these receptors are under tight cellular regulation. The molecular and cellular mechanisms that control the postsynaptic insertion, arrangement, and lifetime of surface-expressed AMPARs are the subject of intense and widespread investigation. For example, there has been an explosion of information about proteins that interact with AMPAR subunits, and these interactors are beginning to provide real insight into the molecular and cellular mechanisms underlying the cell biology of AMPARs. As a result, there has been considerable progress in this field, and the aim of this review is to provide an account of the current state of knowledge.
Collapse
Affiliation(s)
- Claire L Palmer
- Medical Research Council Centre for Synaptic Plasticity, Department of Anatomy, School of Medical Sciences, Bristol University, Bristol, UK
| | | | | |
Collapse
|
22
|
Maltez JM, Nunziato DA, Kim J, Pitt GS. Essential Cavβ modulatory properties are AID-independent. Nat Struct Mol Biol 2005; 12:372-7. [PMID: 15750602 DOI: 10.1038/nsmb909] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Accepted: 02/03/2005] [Indexed: 11/09/2022]
Abstract
Voltage-gated Ca(2+) channel beta (Ca(v)beta) subunits have a highly conserved core consisting of interacting Src homology 3 and guanylate kinase domains, and are postulated to exert their effects through AID, the major interaction site in the pore-forming alpha(1) subunit. This stereotypical interaction does not explain how individual Ca(v)beta subunits modulate alpha(1) subunits differentially. Here we show that AID is neither necessary nor sufficient for critical Ca(v)beta regulatory properties. Complete modulation depends on additional contacts that are exclusive of AID and not revealed in recent crystal structures. These data offer a new context for understanding Ca(v)beta modulation, suggesting that the AID interaction orients the Ca(v)beta core so as to permit additional isoform-specific Ca(v)alpha(1)-Ca(v)beta interactions that underlie the particular regulation seen with each Ca(v)alpha(1)-Ca(v)beta pair, rather than as the main site of regulation.
Collapse
Affiliation(s)
- Janet M Maltez
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
| | | | | | | |
Collapse
|
23
|
Jing-Ping Z, Tian QB, Sakagami H, Kondo H, Endo S, Suzuki T. p55 protein is a member of PSD scaffold proteins in the rat brain and interacts with various PSD proteins. ACTA ACUST UNITED AC 2005; 135:204-16. [PMID: 15857683 DOI: 10.1016/j.molbrainres.2004.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2004] [Revised: 12/12/2004] [Accepted: 12/20/2004] [Indexed: 10/25/2022]
Abstract
p55 is a membrane-associated guanylate kinase (MAGuK) family member that consists of a single PDZ followed by SH3, HOOK and guanylate kinase (GuK or GK) domains. We investigated rat p55 (r-p55) in the brain. r-p55 mRNA was expressed widely in various tissues and in various regions of the brain. r-p55 protein was also expressed widely in various rat tissues, including brain and erythrocytes. The protein was enriched in the synaptic plasma membrane and postsynaptic density (PSD) fractions of the forebrain. An immunocytochemical study using cultured cortical neurons suggested postsynaptic localization of r-p55 protein. Pull-down assay showed that r-p55 protein interacted with r-p55 itself and various PSD proteins, such as PSD-95, SAP97, GKAP, CASK, GRIP, neuroligin, cadherin, tubulin, actin, alpha-internexin, neurofilament-L and Ca(2+)/calmodulin-dependent protein kinase II, through its PDZ, SH3, HOOK or GK domains. The interaction with PSD-95 was found to occur between the PDZ domains of PSD-95 and the HOOK and GK domains of r-p55 protein. These findings, together with the presence of r-p55 puncta in a period of early synaptogenesis, suggest that r-p55 protein functions as one of postsynaptic scaffold component in an early stage of synaptogenesis in the brain. r-p55 protein may form a basic structure, which interlinks diverse functional molecules of the PSD necessary for postsynaptic signaling and synaptic adhesion.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Antibody Specificity
- Blotting, Northern
- Blotting, Western/methods
- Brain/cytology
- Brain/embryology
- Brain/metabolism
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cells, Cultured
- Cloning, Molecular/methods
- DNA, Complementary/metabolism
- Disks Large Homolog 4 Protein
- Electrophoretic Mobility Shift Assay/methods
- Embryo, Mammalian
- Fluorescent Antibody Technique/methods
- Gene Expression Regulation, Developmental/physiology
- Guanylate Kinases
- Immunoprecipitation/methods
- In Situ Hybridization/methods
- Intracellular Signaling Peptides and Proteins
- Male
- Membrane Proteins
- Multiprotein Complexes/metabolism
- Nerve Tissue Proteins/classification
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/immunology
- Nerve Tissue Proteins/metabolism
- Neurons/metabolism
- Protein Structure, Tertiary/physiology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Signal Transduction
- Subcellular Fractions/metabolism
- Synaptophysin/metabolism
- Time Factors
Collapse
Affiliation(s)
- Zhang Jing-Ping
- Department of Neuroplasticity, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan
| | | | | | | | | | | |
Collapse
|
24
|
Matsubara M, Jing T, Kawamura K, Shimojo N, Titani K, Hashimoto K, Hayashi N. Myristoyl moiety of HIV Nef is involved in regulation of the interaction with calmodulin in vivo. Protein Sci 2005; 14:494-503. [PMID: 15632291 PMCID: PMC2253426 DOI: 10.1110/ps.04969605] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Human immunodeficiency virus Nef is a myristoylated protein expressed early in infection by HIV. In addition to the well known down-regulation of the cell surface receptors CD4 and MHCI, Nef is able to alter T-cell signaling pathways. The ability to alter the cellular signaling pathways suggests that Nef can associate with signaling proteins. In the present report, we show that Nef can interact with calmodulin, the major intracellular receptor for calcium. Coimmunoprecipitation analyses with lysates from the NIH3T3 cell line constitutively expressing the native HIV-1 Nef protein revealed the presence of a stable Nef-calmodulin complex. When lysates from NIH3T3 cells were incubated with calmodulin-agarose beads in the presence of CaCl(2) or EGTA, calcium ion drastically enhanced the interaction between Nef and calmodulin, suggesting that the binding is under the influence of Ca(2+) signaling. Glutathione S-transferase-Nef fusion protein bound directly to calmodulin with high affinity. Using synthetic peptides based on the N-terminal sequence of Nef, we determined that within a 20-amino-acid N-terminal basic domain was sufficient for calmodulin binding. Furthermore, the myristoylated peptide bound to calmodulin with higher affinity than nonmyris-toylated form. Thus, the N-terminal myristoylation domain of Nef plays an important role in interacting with calmodulin. This domain is highly conserved in several HIV-1 Nef variants and resembles the N-terminal domain of NAP-22/CAP23, a myristoylated calmodulin-binder. These results for the interaction between HIV Nef and calmodulin in the cells suggested that the Nef might interfere with intracellular Ca(2+) signaling through calmodulin-mediated interactions in infected cells.
Collapse
Affiliation(s)
- Mamoru Matsubara
- Division of Biomedical Polymer Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan
| | | | | | | | | | | | | |
Collapse
|
25
|
Müller SL, Portwich M, Schmidt A, Utepbergenov DI, Huber O, Blasig IE, Krause G. The tight junction protein occludin and the adherens junction protein alpha-catenin share a common interaction mechanism with ZO-1. J Biol Chem 2004; 280:3747-56. [PMID: 15548514 DOI: 10.1074/jbc.m411365200] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The exact sites, structures, and molecular mechanisms of interaction between junction organizing zona occludence protein 1 (ZO-1) and the tight junction protein occludin or the adherens junction protein alpha-catenin are unknown. Binding studies by surface plasmon resonance spectroscopy and peptide mapping combined with comparative modeling utilizing crystal structures led for the first time to a molecular model revealing the binding of both occludin and alpha-catenin to the same binding site in ZO-1. Our data support a concept that ZO-1 successively associates with alpha-catenin at the adherens junction and occludin at the tight junction. Strong spatial evidence indicates that the occludin C-terminal coiled-coil domain dimerizes and interacts finally as a four-helix bundle with the identified structural motifs in ZO-1. The helix bundle of occludin406-521 and alpha-catenin509-906 interacts with the hinge region (ZO-1591-632 and ZO-1591-622, respectively) and with (ZO-1726-754 and ZO-1756-781) in the GuK domain of ZO-1 containing coiled-coil and alpha-helical structures, respectively. The selectivity of both protein-protein interactions is defined by complementary shapes and charges between the participating epitopes. In conclusion, a common molecular mechanism of forming an intermolecular helical bundle between the hinge region/GuK domain of ZO-1 and alpha-catenin and occludin is identified as a general molecular principle organizing the association of ZO-1 at adherens and tight junctions.
Collapse
Affiliation(s)
- Sebastian L Müller
- Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Charité-Campus Mitte, 10117 Berlin, Germany, and Charité-Campus Benjamin Franklin, 12203 Berlin, Germany
| | | | | | | | | | | | | |
Collapse
|
26
|
Rich RL, Myszka DG. A survey of the year 2002 commercial optical biosensor literature. J Mol Recognit 2004; 16:351-82. [PMID: 14732928 DOI: 10.1002/jmr.649] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have compiled 819 articles published in the year 2002 that involved commercial optical biosensor technology. The literature demonstrates that the technology's application continues to increase as biosensors are contributing to diverse scientific fields and are used to examine interactions ranging in size from small molecules to whole cells. Also, the variety of available commercial biosensor platforms is increasing and the expertise of users is improving. In this review, we use the literature to focus on the basic types of biosensor experiments, including kinetics, equilibrium analysis, solution competition, active concentration determination and screening. In addition, using examples of particularly well-performed analyses, we illustrate the high information content available in the primary response data and emphasize the impact of including figures in publications to support the results of biosensor analyses.
Collapse
Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
| | | |
Collapse
|
27
|
Van Petegem F, Clark KA, Chatelain FC, Minor DL. Structure of a complex between a voltage-gated calcium channel beta-subunit and an alpha-subunit domain. Nature 2004; 429:671-5. [PMID: 15141227 PMCID: PMC3076333 DOI: 10.1038/nature02588] [Citation(s) in RCA: 339] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Accepted: 04/23/2004] [Indexed: 11/08/2022]
Abstract
Voltage-gated calcium channels (Ca(V)s) govern muscle contraction, hormone and neurotransmitter release, neuronal migration, activation of calcium-dependent signalling cascades, and synaptic input integration. An essential Ca(V) intracellular protein, the beta-subunit (Ca(V)beta), binds a conserved domain (the alpha-interaction domain, AID) between transmembrane domains I and II of the pore-forming alpha(1) subunit and profoundly affects multiple channel properties such as voltage-dependent activation, inactivation rates, G-protein modulation, drug sensitivity and cell surface expression. Here, we report the high-resolution crystal structures of the Ca(V)beta2a conserved core, alone and in complex with the AID. Previous work suggested that a conserved region, the beta-interaction domain (BID), formed the AID-binding site; however, this region is largely buried in the Ca(V)beta core and is unavailable for protein-protein interactions. The structure of the AID-Ca(V)beta2a complex shows instead that Ca(V)beta2a engages the AID through an extensive, conserved hydrophobic cleft (named the alpha-binding pocket, ABP). The ABP-AID interaction positions one end of the Ca(V)beta near the intracellular end of a pore-lining segment, called IS6, that has a critical role in Ca(V) inactivation. Together, these data suggest that Ca(V)betas influence Ca(V) gating by direct modulation of IS6 movement within the channel pore.
Collapse
Affiliation(s)
- Filip Van Petegem
- Cardiovascular Research Institute, Department of Biochemistry and Biophysics, University of California San Francisco, 513 Parnassus Avenue, Box 0130, San Francisco, California 94143, USA
| | | | | | | |
Collapse
|
28
|
Bachmann A, Timmer M, Sierralta J, Pietrini G, Gundelfinger ED, Knust E, Thomas U. Cell type-specific recruitment of Drosophila Lin-7 to distinct MAGUK-based protein complexes defines novel roles for Sdt and Dlg-S97. J Cell Sci 2004; 117:1899-909. [PMID: 15039455 DOI: 10.1242/jcs.01029] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Stardust (Sdt) and Discs-Large (Dlg) are membrane-associated guanylate kinases (MAGUKs) involved in the organization of supramolecular protein complexes at distinct epithelial membrane compartments in Drosophila. Loss of either Sdt or Dlg affects epithelial development with severe effects on apico-basal polarity. Moreover, Dlg is required for the structural and functional integrity of synaptic junctions. Recent biochemical and cell culture studies have revealed that various mammalian MAGUKs can interact with mLin-7/Veli/MALS, a small PDZ-domain protein. To substantiate these findings for their in vivo significance with regard to Sdt- and Dlg-based protein complexes, we analyzed the subcellular distribution of Drosophila Lin-7 (DLin-7) and performed genetic and biochemical assays to characterize its interaction with either of the two MAGUKs. In epithelia, Sdt mediates the recruitment of DLin-7 to the subapical region, while at larval neuromuscular junctions, a particular isoform of Dlg, Dlg-S97, is required for postsynaptic localization of DLin-7. Ectopic expression of Dlg-S97 in epithelia, however, was not sufficient to induce a redistribution of DLin-7. These results imply that the recruitment of DLin-7 to MAGUK-based protein complexes is defined by cell-type specific mechanisms and that DLin-7 acts downstream of Sdt in epithelia and downstream of Dlg at synapses.
Collapse
Affiliation(s)
- André Bachmann
- Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | | | | | | | | | | | | |
Collapse
|
29
|
Godreau D, Vranckx R, Maguy A, Goyenvalle C, Hatem SN. Different isoforms of synapse-associated protein, SAP97, are expressed in the heart and have distinct effects on the voltage-gated K+ channel Kv1.5. J Biol Chem 2003; 278:47046-52. [PMID: 12970345 DOI: 10.1074/jbc.m308463200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The SAP97 isoforms differ by alternatively spliced insertion domains that regulate protein localization and oligomerization. We used reverse transcription-PCR to identify SAP97 isoforms of human and rat myocardium. In Chinese hamster ovary cells, cloned protein expression was studied using Western blot, confocal imaging of green fluorescent protein-tagged proteins, and patch clamp technique. The two main cardiac SAP97 isoforms contained both I3 and I1B inserts and differed by the I1A insert. Both isoforms co-precipitated with hKv1.5 channels. Only the isoform lacking I1A increased the current (by 215 +/- 22%), whatever the level of channel expression. To examine the involvement of the proline-rich I1A insert in the effect of SAP97, a W623F mutation in the Src homology 3 domain was created, and that restored the effect of the SAP97 on current. SAP97 isoform containing an I1A and I2 domain instead of the I3 domain stimulated the current, whereas SAP97 after deletion of the Src homology 3 and guanylate kinase-like domains did not. In cells co-expressing I3(+I1A) or I3(-I1A), green fluorescent protein-tagged Kv1.5 channels were organized in plaque-like structures at the plasma membrane level, whereas intracellular aggregates of channels predominated with the I2 isoform. The two cardiac SAP97 isoforms have different effects on the hKv1.5 current, depending on their capacity to form channel clusters.
Collapse
Affiliation(s)
- David Godreau
- INSERM 460, Medical Hospital Xavier Bichat-Claude Bernard, 46 Rue Henri Huchard, 75018 Paris, France
| | | | | | | | | |
Collapse
|
30
|
Seabold GK, Burette A, Lim IA, Weinberg RJ, Hell JW. Interaction of the tyrosine kinase Pyk2 with the N-methyl-D-aspartate receptor complex via the Src homology 3 domains of PSD-95 and SAP102. J Biol Chem 2003; 278:15040-8. [PMID: 12576483 DOI: 10.1074/jbc.m212825200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein-tyrosine kinase Pyk2/CAKbeta/CADTK is a key activator of Src in many cells. At hippocampal synapses, induction of long term potentiation requires the Pyk2/Src signaling pathway, which up-regulates the activity of N-methyl-d-aspartate-type glutamate receptors. Because localization of protein kinases close to their substrates is crucial for effective phosphorylation, we investigated how Pyk2 might be recruited to the N-methyl-d-aspartate receptor complex. This interaction is mediated by PSD-95 and its homolog SAP102. Both proteins colocalize with Pyk2 at postsynaptic dendritic spines in the cerebral cortex. The proline-rich regions in the C-terminal half of Pyk2 bind to the SH3 domain of PSD-95 and SAP102. The SH3 and guanylate kinase homology (GK) domain of PSD-95 and SAP102 interact intramolecularly, but the physiological significance of this interaction has been unclear. We show that Pyk2 effectively binds to the Src homology 3 (SH3) domain of SAP102 only when the GK domain is removed from the SH3 domain. Characterization of PSD-95 and SAP102 as adaptor proteins for Pyk2 fills a critical gap in the understanding of the spatial organization of the Pyk2-Src signaling pathway at the postsynaptic site and reveals a physiological function of the intramolecular SH3-GK domain interaction in SAP102.
Collapse
Affiliation(s)
- Gail K Seabold
- Department of Pharmacology, University of Wisconsin, Madison, Wisconsin 53706-1532, USA
| | | | | | | | | |
Collapse
|