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Zheng L, Shi W, Liu B, Duan B, Sorgen P. Evaluation of Tyrosine Kinase Inhibitors Loaded Injectable Hydrogels for Improving Connexin43 Gap Junction Intercellular Communication. ACS Appl Mater Interfaces 2024; 16:1985-1998. [PMID: 38175743 PMCID: PMC11061860 DOI: 10.1021/acsami.3c10923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Myocardial infarction (MI) is one of the leading causes of death in the developed world, and the loss of cardiomyocytes plays a critical role in the pathogenesis of heart failure. Implicated in this process is a decrease in gap junction intercellular communication due to remodeling of Connexin43 (Cx43). We previously identified that intraperitoneal injection of the Pyk2 inhibitor PF4618433 reduced infarct size, maintained Cx43 at the intercalated disc in left ventricle hypertrophic myocytes, and improved cardiac function in an MI animal model of heart failure. With the emergence of injectable hydrogels as a therapeutic toward the regeneration of cardiac tissue after MI, here, we provide proof of concept that the release of tyrosine kinase inhibitors from hydrogels could have beneficial effects on cardiomyocytes. We developed an injectable hydrogel consisting of thiolated hyaluronic acid and P123-maleimide micelles that can incorporate PF4618433 as well as the Src inhibitor Saracatinib and achieved sustained release (of note, Src activates Pyk2). Using neonatal rat ventricular myocytes in the presence of a phorbol ester, endothelin-1, or phenylephrine to stimulate cardiac hypertrophy, the release of PF4618433 from the hydrogel had the same ability to decrease Cx43 tyrosine phosphorylation and maintain Cx43 localization at the plasma membrane as when directly added to the growth media. Additional beneficial effects included decreases in apoptosis, the hypertrophic marker atrial natriuretic peptide (ANP), and serine kinases upregulated in hypertrophy. Finally, the presence of both PF4618433 and Saracatinib further decreased the level of ANP and apoptosis than each inhibitor alone, suggesting that a combinatorial approach may be most beneficial. These findings provide the groundwork to test if tyrosine kinase inhibitor release from hydrogels will have a beneficial effect in an animal model of MI-induced heart failure.
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Affiliation(s)
- Li Zheng
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Wen Shi
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bo Liu
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Bin Duan
- Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Division of Cardiology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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2
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Kshirsagar PG, Gulati M, Junker WM, Aithal A, Spagnol G, Das S, Mallya K, Gautam SK, Kumar S, Sorgen P, Pandey KK, Batra SK, Jain M. Characterization of recombinant β subunit of human MUC4 mucin (rMUC4β). Sci Rep 2021; 11:23730. [PMID: 34887447 PMCID: PMC8660890 DOI: 10.1038/s41598-021-02860-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 11/03/2021] [Indexed: 12/30/2022] Open
Abstract
MUC4 is a transmembrane mucin expressed on various epithelial surfaces, including respiratory and gastrointestinal tracts, and helps in their lubrication and protection. MUC4 is also aberrantly overexpressed in various epithelial malignancies and functionally contributes to cancer development and progression. MUC4 is putatively cleaved at the GDPH site into a mucin-like α-subunit and a membrane-tethered growth factor-like β-subunit. Due to the presence of several functional domains, the characterization of MUC4β is critical for understanding MUC4 biology. We developed a method to produce and purify multi-milligram amounts of recombinant MUC4β (rMUC4β). Purified rMUC4β was characterized by Far-UV CD and I-TASSER-based protein structure prediction analyses, and its ability to interact with cellular proteins was determined by the affinity pull-down assay. Two of the three EGF-like domains exhibited typical β-fold, while the third EGF-like domain and vWD domain were predominantly random coils. We observed that rMUC4β physically interacts with Ezrin and EGFR family members. Overall, this study describes an efficient and simple strategy for the purification of biologically-active rMUC4β that can serve as a valuable reagent for a variety of biochemical and functional studies to elucidate MUC4 function and generating domain-specific antibodies and vaccines for cancer immunotherapy.
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Affiliation(s)
- Prakash G Kshirsagar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Mansi Gulati
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Wade M Junker
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA.,Sanguine Diagnostics and Therapeutics, Omaha, NE, USA
| | - Abhijit Aithal
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Srustidhar Das
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Kavita Mallya
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Shailendra K Gautam
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Sushil Kumar
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA
| | - Krishan K Pandey
- Department of Molecular Microbiology and Immunology, Saint Louis University Health Sciences Center, St. Louis, MO, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA. .,Sanguine Diagnostics and Therapeutics, Omaha, NE, USA. .,Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA. .,Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA.
| | - Maneesh Jain
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Nebraska Medical Center, 985870 Nebraska Medical Center, Omaha, NE, 68198-5870, USA. .,Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.
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3
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Banerjee K, Gautam SK, Kshirsagar P, Ross KA, Spagnol G, Sorgen P, Wannemuehler MJ, Narasimhan B, Solheim JC, Kumar S, Batra SK, Jain M. Amphiphilic polyanhydride-based recombinant MUC4β-nanovaccine activates dendritic cells. Genes Cancer 2019; 10:52-62. [PMID: 31258832 PMCID: PMC6584211 DOI: 10.18632/genesandcancer.189] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mucin 4 (MUC4) is a high molecular weight glycoprotein that is differentially overexpressed in pancreatic cancer (PC), functionally contributes to disease progression, and correlates with poor survival. Further, due to its aberrant glycosylation and extensive splicing, MUC4 is a potential target for cancer immunotherapy. Our previous studies have demonstrated the utility of amphiphilic polyanhydride nanoparticles as a useful platform for the development of protein-based prophylactic and therapeutic vaccines. In the present study, we encapsulated purified recombinant human MUC4-beta (MUC4β) protein in polyanhydride (20:80 CPTEG:CPH) nanoparticles (MUC4β-nanovaccine) and evaluated its ability to activate dendritic cells and induce adaptive immunity. Immature dendritic cells when pulsed with MUC4β-nanovaccine exhibited significant increase in the surface expressions of MHC I and MHC II and costimulatory molecules (CD80 and CD86), as well as, secretion of pro-inflammatory cytokines (IFN-γ, IL-6, and IL-12) as compared to cells exposed to MUC4β alone or MUC4β mixed with blank nanoparticles (MUC4β+NP). Following immunization, as compared to the other formulations, MUC4β-nanovaccine elicited higher IgG2b to IgG1 ratio of anti-MUC4β-antibodies suggesting a predominantly Th1-like class switching. Thus, our findings demonstrate MUC4β-nanovaccine as a novel platform for PC immunotherapy.
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Affiliation(s)
- Kasturi Banerjee
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shailendra K Gautam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Prakash Kshirsagar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kathleen A Ross
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael J Wannemuehler
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA.,Nanovaccine Institute, Ames, IA and Omaha, NE, USA
| | - Balaji Narasimhan
- Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA.,Nanovaccine Institute, Ames, IA and Omaha, NE, USA
| | - Joyce C Solheim
- The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.,Nanovaccine Institute, Ames, IA and Omaha, NE, USA.,Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sushil Kumar
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.,The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.,Nanovaccine Institute, Ames, IA and Omaha, NE, USA
| | - Maneesh Jain
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.,The Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA.,Nanovaccine Institute, Ames, IA and Omaha, NE, USA
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4
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Banerjee K, Gautam S, Nasser WM, Kshirsagar P, Ross K, Spagnol G, Aithal A, Sorgen P, Batra SK, Kumar S, Narasimhan B, Jain M. Abstract 3678: Muc4 nanovaccine and checkpoint blockade based combination immunotherapy for pancreatic cancer. Immunology 2017. [DOI: 10.1158/1538-7445.am2017-3678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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5
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Bahl K, Xie S, Spagnol G, Sorgen P, Naslavsky N, Caplan S. EHD3 Protein Is Required for Tubular Recycling Endosome Stabilization, and an Asparagine-Glutamic Acid Residue Pair within Its Eps15 Homology (EH) Domain Dictates Its Selective Binding to NPF Peptides. J Biol Chem 2016; 291:13465-78. [PMID: 27189942 DOI: 10.1074/jbc.m116.716407] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 11/06/2022] Open
Abstract
An elaborate network of dynamic lipid membranes, termed tubular recycling endosomes (TRE), coordinates the process of endocytic recycling in mammalian cells. The C-terminal Eps15 homology domain (EHD)-containing proteins have been implicated in the bending and fission of TRE, thus regulating endocytic recycling. EHD proteins have an EH domain that interacts with proteins containing an NPF motif. We found that NPF-containing EHD1 interaction partners such as molecules interacting with CasL-like1 (MICAL-L1) and Syndapin2 are essential for TRE biogenesis. Also crucial for TRE biogenesis is the generation of phosphatidic acid, an essential lipid component of TRE that serves as a docking point for MICAL-L1 and Syndapin2. EHD1 and EHD3 have 86% amino acid identity; they homo- and heterodimerize and partially co-localize to TRE. Despite their remarkable identity, they have distinct mechanistic functions. EHD1 induces membrane vesiculation, whereas EHD3 supports TRE biogenesis and/or stabilization by an unknown mechanism. While using phospholipase D inhibitors (which block the conversion of glycerophospholipids to phosphatidic acid) to deplete cellular TRE, we observed that, upon inhibitor washout, there was a rapid and dramatic regeneration of MICAL-L1-marked TRE. Using this "synchronized" TRE biogenesis system, we determined that EHD3 is involved in the stabilization of TRE rather than in their biogenesis. Moreover, we identify the residues Ala-519/Asp-520 of EHD1 and Asn-519/Glu-520 of EHD3 as defining the selectivity of these two paralogs for NPF-containing binding partners, and we present a model to explain the atomic mechanism and provide new insight for their differential roles in vesiculation and tubulation, respectively.
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Affiliation(s)
- Kriti Bahl
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Shuwei Xie
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Gaelle Spagnol
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Paul Sorgen
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Naava Naslavsky
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
| | - Steve Caplan
- From the Department of Biochemistry and Molecular Biology and Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5870
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6
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Das S, Majhi PD, Al-Mugotir MH, Rachagani S, Sorgen P, Batra SK. Membrane proximal ectodomain cleavage of MUC16 occurs in the acidifying Golgi/post-Golgi compartments. Sci Rep 2015; 5:9759. [PMID: 26044153 PMCID: PMC4456727 DOI: 10.1038/srep09759] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 03/13/2015] [Indexed: 12/29/2022] Open
Abstract
MUC16, precursor of the most widely used ovarian cancer biomarker CA125, is up
regulated in multiple malignancies and is associated with poor prognosis. While the
pro-tumorigenic and metastatic roles of MUC16 are ascribed to the cell-associated
carboxyl-terminal MUC16 (MUC16-Cter), the exact biochemical nature of MUC16 cleavage
generating MUC16-Cter has remained unknown. Using different lengths of dual-epitope
(N-terminal FLAG- and C-terminal HA-Tag) tagged C-terminal MUC16 fragments, we
demonstrate that MUC16 cleavage takes place in the juxta-membrane ectodomain stretch
of twelve amino acids that generates a ~17 kDa cleaved product and is
distinct from the predicted sites. This was further corroborated by domain swapping
experiment. Further, the cleavage of MUC16 was found to take place in the
Golgi/post-Golgi compartments and is dependent on the acidic pH in the secretory
pathway. A similar pattern of ~17 kDa cleaved MUC16 was observed in
multiple cell types eliminating the possibility of cell type specific phenomenon.
MUC16-Cter translocates to the nucleus in a cleavage dependent manner and binds to
the chromatin suggesting its involvement in regulation of gene expression. Taken
together, we demonstrate for the first time the oft-predicted cleavage of MUC16 that
is critical in designing successful therapeutic interventions based on MUC16.
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Affiliation(s)
- Srustidhar Das
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Prabin D Majhi
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Mona H Al-Mugotir
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Surinder K Batra
- 1] Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA [2] Department of Pathology, University of Nebraska Medical Center, Omaha, NE 68198, USA [3] Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
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7
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Stauch K, Kieken F, Sorgen P. Characterization of the structure and intermolecular interactions between the connexin 32 carboxyl-terminal domain and the protein partners synapse-associated protein 97 and calmodulin. J Biol Chem 2012; 287:27771-88. [PMID: 22718765 PMCID: PMC3431650 DOI: 10.1074/jbc.m112.382572] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 06/20/2012] [Indexed: 12/20/2022] Open
Abstract
In Schwann cells, connexin 32 (Cx32) can oligomerize to form intracellular gap junction channels facilitating a shorter pathway for metabolite diffusion across the layers of the myelin sheath. The mechanisms of Cx32 intracellular channel regulation have not been clearly defined. However, Ca(2+), pH, and the phosphorylation state can regulate Cx32 gap junction channels, in addition to the direct interaction of protein partners with the carboxyl-terminal (CT) domain. In this study, we used different biophysical methods to determine the structure and characterize the interaction of the Cx32CT domain with the protein partners synapse-associated protein 97 (SAP97) and calmodulin (CaM). Our results revealed that the Cx32CT is an intrinsically disordered protein that becomes α-helical upon binding CaM. We identified the GUK domain as the minimal SAP97 region necessary for the Cx32CT interaction. The Cx32CT residues affected by the binding of CaM and the SAP97 GUK domain were determined as well as the dissociation constants for these interactions. We characterized three Cx32CT Charcot-Marie-Tooth disease mutants (R219H, R230C, and F235C) and identified that whereas they all formed functional channels, they all showed reduced binding affinity for SAP97 and CaM. Additionally, we report that in RT4-D6P2T rat schwannoma cells, Cx32 is differentially phosphorylated and exists in a complex with SAP97 and CaM. Our studies support the importance of protein-protein interactions in the regulation of Cx32 gap junction channels and myelin homeostasis.
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Affiliation(s)
- Kelly Stauch
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Fabien Kieken
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
| | - Paul Sorgen
- From the Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198
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Sharma M, Jovic M, Kieken F, Naslavsky N, Sorgen P, Caplan S. A model for the role of EHD1-containing membrane tubules in endocytic recycling. Commun Integr Biol 2010; 2:431-3. [PMID: 19907710 DOI: 10.4161/cib.2.5.9157] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Accepted: 06/02/2009] [Indexed: 11/19/2022] Open
Abstract
The C-terminal Eps15 homology domain-containing protein, EHD1, is an important regulator of receptor recycling back to the plasma membrane. In addition to its vesicular localization, EHD1 also localizes to a unique array of tubular membrane structures that emanate from the endocytic recycling compartment. While these structures have been described over seven years ago, addressing their lipid composition and physiological function has been challenging. Moreover, it was not known whether EHD1 itself induces tubule formation, or whether it localizes to pre-existing tubular membrane structures. We have demonstrated that in vivo, EHD1 localizes to pre-existing tubular membranes that contain both phosphatidylinositol-4-phosphate and phosphatidylinositol-(4,5)-bisphosphate. Moreover, we have determined that 'non-tubular' EHD1 mutants with a single residue substitution do not efficiently facilitate receptor recycling. Our data suggest that EHD1-associated tubules are required for efficient recycling and we propose models that describe the potential mechanisms by which EHD1 functions.
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Affiliation(s)
- Mahak Sharma
- Department of Biochemistry and Molecular Biology and Eppley Cancer Center; University of Nebraska Medical Center, Omaha, NE 68198-5870, USA
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Pfenniger A, Derouette JP, Verma V, Lin X, Foglia B, Coombs W, Roth I, Satta N, Dunoyer-Geindre S, Sorgen P, Taffet S, Kwak BR, Delmar M. Gap junction protein Cx37 interacts with endothelial nitric oxide synthase in endothelial cells. Arterioscler Thromb Vasc Biol 2010; 30:827-34. [PMID: 20081116 PMCID: PMC2930827 DOI: 10.1161/atvbaha.109.200816] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The gap junction protein connexin37 (Cx37) plays an important role in cell-cell communication in the vasculature. A C1019T Cx37 gene polymorphism, encoding a P319S substitution in the regulatory C terminus of Cx37 (Cx37CT), correlates with arterial stenosis and myocardial infarction in humans. This study was designed to identify potential binding partners for Cx37CT and to determine whether the polymorphism modified this interaction. METHODS AND RESULTS Using a high-throughput phage display, we retrieved 2 binding motifs for Cx37CT: WHK ... [K,R]XP ... and FHK ... [K,R]XXP ... , the first being more common for Cx37CT-319P and the second more common for Cx37CT-319S. One of the peptides (WHRTPRLPPPVP) showed 77.7% homology with residues 843 to 854 of endothelial nitric oxide synthase (eNOS). In vitro binding of this peptide or of the homologous eNOS sequence to both Cx37CT isoforms was confirmed by cross-linking and surface plasmon resonance. Electrophysiological analysis of Cx37 single channel activity in transfected N2a cells showed that eNOS-like and eNOS(843-854) increased the frequency of events with conductances higher than 300 pS. We demonstrated that eNOS coimmunoprecipitated with Cx37 in a mouse endothelial cell (EC) line (bEnd.3), human primary ECs, and a human EC line transfected with Cx37-319P or Cx37-319S. Cx37 and eNOS colocalized at EC membranes. Moreover, a dose-dependent increase in nitric oxide production was observed in ECs treated with Cx37 antisense. CONCLUSIONS Overall, our data show for the first time a functional and specific interaction between eNOS and Cx37. This interaction may be relevant for the control of vascular physiology both in health and in disease.
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Affiliation(s)
- Anna Pfenniger
- Division of Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Geneva, Switzerland.
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Virgil KL, Sorgen P. Characterization of the Cx32/hDlg Complex and its Role in Tumor Suppression. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.3817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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11
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Duffy HS, Sorgen P, Coombs W, Taffet S, Girvin M, Delmar M, Spray DC. Acidification-induced changes in Cx43 protein-protein interactions. J Neurochem 2008. [DOI: 10.1046/j.1471-4159.81.s1.42_9.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Bouvier D, Kieken F, Kellezi A, Sorgen P. Structural changes in the carboxyl terminus of the gap junction protein connexin 40 caused by the interaction with c-Src and zonula occludens-1. Cell Commun Adhes 2008; 15:107-18. [PMID: 18649183 PMCID: PMC2917908 DOI: 10.1080/15419060802014347] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
c-Src can disrupt the connexin 43 (Cx43) and zonula occludens-1 (ZO-1) interaction, leading to down-regulation of gap junction intercellular communication. Previously, the authors characterized the interaction of domains from these proteins with the carboxyl terminus of Cx43 (Cx43CT) and found that binding of the c-Src SH3 domain to Cx43CT disrupted the Cx43CT/ZO-1 PDZ-2 domain complex. Because Cx43 and Cx40 form heteromeric connexons and display similar mechanisms of pH regulation, the authors addressed whether Cx40CT interacts with these domains in a similar manner as Cx43CT. Nuclear magnetic resonance (NMR) data indicate that Cx40CT is an intrinsically disordered protein. NMR titrations determined that PDZ-2 affected the last 28 Cx40CT residues and SH3 shifted numerous amino-terminal Cx40CT residues. Finally, the Cx40CT/PDZ-2 complex was unaffected by SH3 and both domains interacted simultaneously with Cx40CT. This result differs from when the same experiment was performed with Cx43CT, suggesting different mechanisms of regulation exist between connexin isoforms, even when involving the same molecular partners.
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Affiliation(s)
- Denis Bouvier
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Fabien Kieken
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Admir Kellezi
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Paul Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198
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Delmar M, Coombs W, Sorgen P, Duffy HS, Taffet SM. Structural bases for the chemical regulation of Connexin43 channels. Cardiovasc Res 2004; 62:268-75. [PMID: 15094347 DOI: 10.1016/j.cardiores.2003.12.030] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Revised: 11/19/2003] [Accepted: 12/10/2003] [Indexed: 10/26/2022] Open
Abstract
Connexins proteins associate with a variety of catalytic and non-catalytic molecules. Also, different domains of connexin can bind to each other, providing a mechanism for channel regulation. Here, we review some of these associations, placing particular emphasis on the intramolecular interactions that regulate Connexin43 (Cx43). We also describe some novel methods that allow for the characterization of protein-protein interactions such as those observed in the cardiac gap junction protein Connexin43. Overall, intra- and inter-molecular interactions may regulate gap junctions to filter the passage of molecular messages between cells at the appropriate time and between the appropriate cells. As a potential area for future investigations, we also speculate as to whether some of the inter-molecular interactions involving connexins lead to modifications in the function of the associated protein, rather than on the function of connexin itself.
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Affiliation(s)
- Mario Delmar
- Department of Pharmacology, SUNY Upstate Medical University, 766 Irving Ave, Syracuse, NY 13210, USA.
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