1
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Naik AR, Formosa BJ, Pulvender RG, Liyanaarachchi AG, Jena BP. vH +-ATPase-induced intracellular acidification is critical to glucose-stimulated insulin secretion in beta cells. Histochem Cell Biol 2020; 153:279-285. [PMID: 31901974 DOI: 10.1007/s00418-019-01841-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2019] [Indexed: 10/25/2022]
Abstract
Swelling of secretory vesicles is critical for the regulated release of intra-vesicular contents from cells during secretion. At the secretory vesicle membrane of the exocrine pancreas and neurons, GTP-binding G proteins, vH+-ATPase, potassium channels and AQP water channels, are among the players implicated in vesicle volume regulation. Here we report in the endocrine insulin-secreting MIN6 cells, the similar requirement of vH+-ATPase-mediated intracellular acidification on glucose-stimulated insulin release. MIN6 cells exposed to the vH+-ATPase inhibitor Bafilomycin A show decreased acidification of the cytosolic compartment that include insulin-carrying granules. Additionally, a loss of insulin granules near the cell plasma membrane following Bafilomycin A treatment, suggests impaired transport of insulin granules and consequent decrease in glucose-stimulated insulin secretion and accumulation of intracellular insulin. These results suggest that vH+-ATPase-mediated intracellular acidification is required for insulin secretion in beta cells.
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Affiliation(s)
- Akshata R Naik
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Brent J Formosa
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Rishika G Pulvender
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Asiri G Liyanaarachchi
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA
| | - Bhanu P Jena
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, 48201, USA. .,NanoBioScience Institute, Wayne State University, Detroit, MI, 48201, USA. .,Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, 540 E. Canfield, 5245 Scott Hall, Detroit, MI, 48201, USA.
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2
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Hou X, Wu Q, Rajagopalan C, Zhang C, Bouhamdan M, Wei H, Chen X, Zaman K, Li C, Sun X, Chen S, Frizzell RA, Sun F. CK19 stabilizes CFTR at the cell surface by limiting its endocytic pathway degradation. FASEB J 2019; 33:12602-12615. [PMID: 31450978 DOI: 10.1096/fj.201901050r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Protein interactions that stabilize the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) at the apical membranes of epithelial cells have not yet been fully elucidated. We identified keratin 19 (CK19 or K19) as a novel CFTR-interacting protein. CK19 overexpression stabilized both wild-type (WT)-CFTR and Lumacaftor (VX-809)-rescued F508del-CFTR (where F508del is the deletion of the phenylalanine residue at position 508) at the plasma membrane (PM), promoting Cl- secretion across human bronchial epithelial (HBE) cells. CK19 prevention of Rab7A-mediated lysosomal degradation was a key mechanism in apical CFTR stabilization. Unexpectedly, CK19 expression was decreased by ∼40% in primary HBE cells from homogenous F508del patients with CF relative to non-CF controls. CK19 also positively regulated multidrug resistance-associated protein 4 expression at the PM, suggesting that this keratin may regulate the apical expression of other ATP-binding cassette proteins as well as CFTR.-Hou, X., Wu, Q., Rajagopalan, C., Zhang, C., Bouhamdan, M., Wei, H., Chen, X., Zaman, K., Li, C., Sun, X., Chen, S., Frizzell, R. A., Sun, F. CK19 stabilizes CFTR at the cell surface by limiting its endocytic pathway degradation.
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Affiliation(s)
- Xia Hou
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Biochemistry and Molecular Biology, Jiamusi University School of Basic Medicine, Jiamusi, China
| | - Qingtian Wu
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA.,Department of Biochemistry and Molecular Biology, Jiamusi University School of Basic Medicine, Jiamusi, China
| | - Carthic Rajagopalan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Chunbing Zhang
- Department of Biochemistry and Molecular Biology, Jiamusi University School of Basic Medicine, Jiamusi, China
| | - Mohamad Bouhamdan
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Hongguang Wei
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Xuequn Chen
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Khalequz Zaman
- Department of Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Chunying Li
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, Georgia, USA
| | - Xiaonan Sun
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, Georgia, USA
| | - Song Chen
- Institute of Medical Biotechnology, Jiangsu College of Nursing, Huai'an, China
| | - Raymond A Frizzell
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.,Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Fei Sun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
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3
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Wang T, Ma G, Ang CS, Korhonen PK, Koehler AV, Young ND, Nie S, Williamson NA, Gasser RB. High throughput LC-MS/MS-based proteomic analysis of excretory-secretory products from short-term in vitro culture of Haemonchus contortus. J Proteomics 2019; 204:103375. [PMID: 31071474 DOI: 10.1016/j.jprot.2019.05.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/08/2019] [Accepted: 05/02/2019] [Indexed: 12/27/2022]
Abstract
Parasitic nematodes of humans, animals and plants have a major, adverse impact on global health and agricultural production worldwide. To cope with their surrounding environment in and the immune attack from the host, excretory-secretory (ES) proteins are released by nematodes to orchestrate or regulate parasite-host interactions. In the present study, we characterised the ES products from short-term (12 h) in vitro culture of different developmental stages/sexes of Haemonchus contortus (one of the most important parasitic nematodes of livestock animals worldwide) using a high throughput tandem mass-spectrometry, underpinned by the most recent genomic dataset. In total, 878 unique proteins from key developmental stages/sexes (third-stage and fourth-stage larvae, and female and male adults) were identified and quantified with high confidence. Bioinformatic analyses showed noteworthy ES protein alterations during the transition from the free-living to the parasitic phase, especially for proteins which are likely involved in nutrient digestion and acquisition as well as parasite-host interactions, such as proteolytic cascade-related peptidases, glycoside hydrolases, C-type lectins and sperm-coating protein/Tpx/antigen 5/pathogenesis related-1/Sc7 (= SCP/TAPS) proteins. Our findings provide an avenue to better explore interactive processes between the host and this highly significant parasitic nematode, to underpin the search for novel drug and vaccine targets. SIGNIFICANCE: The present study represents a comprehensive proteomic analysis of the secretome of key developmental stages/sexes of H. contortus maintained in short-term in vitro culture. High throughput LC-MS/MS analysis of ES products allowed the identification of a large repertoire of proteins (secretome) and the establishment of a new proteomic database for H. contortus. The secretome of H. contortus undergoes substantial changes during the nematode's transition from free-living to parasitic stages, suggesting a constant adaptation to different environments outside of and within the host animal. Understanding the host-parasite relationship at the molecular level could assist significantly in the development of intervention strategies (i.e. novel drugs and vaccines) against H. contortus and related nematodes.
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Affiliation(s)
- Tao Wang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Guangxu Ma
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Ching-Seng Ang
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Pasi K Korhonen
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Anson V Koehler
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Shuai Nie
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Nicholas A Williamson
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
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4
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Chen M, Lee HK, Moo L, Hanlon E, Stein T, Xia W. Common proteomic profiles of induced pluripotent stem cell-derived three-dimensional neurons and brain tissue from Alzheimer patients. J Proteomics 2018; 182:21-33. [PMID: 29709615 DOI: 10.1016/j.jprot.2018.04.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/03/2018] [Accepted: 04/24/2018] [Indexed: 01/21/2023]
Abstract
We established a unique platform for proteomic analysis of cultured three-dimensional (3D) neurons and brain tissue from Alzheimer's disease (AD) patients. We collected peripheral blood mononuclear cells (PBMC), converted PBMC to induced pluripotent stem cell (iPSC) lines, and differentiated the iPSC into human 3D neuro-spheroids. The postmortem brain tissue from the superior frontal cortex, inferior frontal cortex and cerebellum area of the AD patients was compared to the same regions from the control subjects. Proteomic analysis of 3D neuro-spheroids derived from AD subjects revealed the alteration of a number of proteins involved in axon growth, mitochondrial function, and antioxidant defense. Similar analysis of post-mortem AD brain tissue revealed significant alteration in proteins involved in oxidative stress, neuro-inflammation, along with proteins related to axonal injury. These results clearly indicate that the dysfunction of 3D neurons from AD patients in our in vitro environment is comparable to the post-mortem AD brain tissue in vivo. In conclusion, our study revealed a number of candidate proteins that have important implications in AD pathogenesis and supports the notion that the iPSC-derived 3D neuronal system functions as a model to examine novel aspects of AD pathology. SIGNIFICANCE In this study, we present a unique platform for proteomic analysis of induced pluripotent stem cell-derived three dimensional (3D) neurons and compare the results to those from three regions of post-mortem brain tissue from Alzheimer's disease patients and normal control subjects. Our results show that the dysfunction of 3D neurons from AD patients in our in vitro environment is comparable to the post-mortem AD brain tissue in vivo. Our results revealed several candidate proteins that have important implications in AD pathogenesis.
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Affiliation(s)
- Mei Chen
- Geriatric Research Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States; Department of Environmental Health, Harvard T H Chan School of Public Health, Boston, MA, United States
| | - Han-Kyu Lee
- Geriatric Research Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States
| | - Lauren Moo
- Geriatric Research Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States
| | - Eugene Hanlon
- Office of Research and Development, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States
| | - Thor Stein
- Geriatric Research Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States; Department of Pathology, Boston University School of Medicine, Boston, MA, United States
| | - Weiming Xia
- Geriatric Research Education and Clinical Center, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA, United States; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, United States.
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5
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Zhvania MG, Pochkidze N. Neuronal Porosome Complex: Secretory Machinery at the Nerve Terminal. Discoveries (Craiova) 2017; 5:e77. [PMID: 32309595 PMCID: PMC6941571 DOI: 10.15190/d.2017.7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 01/07/2023] Open
Abstract
Neuronal porosomes are 15 nm cup-shaped lipoprotein secretory machines composed of nearly 30 proteins present at the presynaptic membrane, that have been investigated using multiple imaging modalities, such as electron microscopy, atomic force microscopy, and solution X-ray. Synaptic vesicles transiently dock and fuse at the base of the porosome cup facing the cytosol, by establishing a fusion pore for neurotransmitter release. Studies on the morphology, dynamics, isolation, composition, and reconstitution of the neuronal porosome complex provide a molecular understanding of its structure and function. In the past twenty years, a large body of evidence has accumulated on the involvement of the neuronal porosome proteins in neurotransmission and various neurological disorders. In light of these findings, this review briefly summarizes our current understanding of the neuronal porosome complex, the secretory nanomachine at the nerve terminal.
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Affiliation(s)
- Mzia G. Zhvania
- Institute of Chemical Biology, Ilia State University, 3/5 K. Cholokhashvili Avenue, 0162, Tbilisi, Georgia
- Department of Brain Ultrastructure and Nanoarchitecture, I. Beriitashvili Center of Experimental BioMedicine, 14, Gotua Street, 0160 Tbilisi, Georgia
| | - Nino Pochkidze
- Institute of Chemical Biology, Ilia State University, 3/5 K. Cholokhashvili Avenue, 0162, Tbilisi, Georgia
- Department of Brain Ultrastructure and Nanoarchitecture, I. Beriitashvili Center of Experimental BioMedicine, 14, Gotua Street, 0160 Tbilisi, Georgia
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6
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Mitagvaria NP. Fusion Pore: A Curious Case of Rediscovering Science. Discoveries (Craiova) 2017; 5:e73. [PMID: 32309591 PMCID: PMC6941572 DOI: 10.15190/d.2017.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Affiliation(s)
- Nodar P Mitagvaria
- I. Beritashvili Center of Experimental Biomedicine, 14 Gotua Street, 0160 Tbilisi, Georgia
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7
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Naik AR, Kulkarni SP, Lewis KT, Taatjes DJ, Jena BP. Functional Reconstitution of the Insulin-Secreting Porosome Complex in Live Cells. Endocrinology 2016; 157:54-60. [PMID: 26523491 PMCID: PMC4701877 DOI: 10.1210/en.2015-1653] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Supramolecular cup-shaped lipoprotein structures called porosomes embedded in the cell plasma membrane mediate fractional release of intravesicular contents from cells during secretion. The presence of porosomes, have been documented in many cell types including neurons, acinar cells of the exocrine pancreas, GH-secreting cells of the pituitary, and insulin-secreting pancreatic β-cells. Functional reconstitution of porosomes into artificial lipid membranes, have also been accomplished. Earlier studies on mouse insulin-secreting Min6 cells report 100-nm porosome complexes composed of nearly 30 proteins. In the current study, porosomes have been functionally reconstituted for the first time in live cells. Isolated Min6 porosomes reconstituted into live Min6 cells demonstrate augmented levels of porosome proteins and a consequent increase in the potency and efficacy of glucose-stimulated insulin release. Elevated glucose-stimulated insulin secretion 48 hours after reconstitution, reflects on the remarkable stability and viability of reconstituted porosomes, documenting the functional reconstitution of native porosomes in live cells. These results, establish a new paradigm in porosome-mediated insulin secretion in β-cells.
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Affiliation(s)
- Akshata R Naik
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Sanjana P Kulkarni
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Kenneth T Lewis
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Douglas J Taatjes
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
| | - Bhanu P Jena
- Department of Physiology (A.R.N., S.P.K., K.T.L., B.P.J.), Wayne State University School of Medicine, Detroit, Michigan 48201; and Department of Pathology and Laboratory Medicine (D.J.T.), Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, Vermont 05405
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8
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Abstract
Cup-shaped secretory portals at the cell plasma membrane called porosomes mediate the precision release of intravesicular material from cells. Membrane-bound secretory vesicles transiently dock and fuse at the base of porosomes facing the cytosol to expel pressurized intravesicular contents from the cell during secretion. The structure, isolation, composition, and functional reconstitution of the neuronal porosome complex have greatly progressed, providing a molecular understanding of its function in health and disease. Neuronal porosomes are 15 nm cup-shaped lipoprotein structures composed of nearly 40 proteins, compared to the 120 nm nuclear pore complex composed of >500 protein molecules. Membrane proteins compose the porosome complex, making it practically impossible to solve its atomic structure. However, atomic force microscopy and small-angle X-ray solution scattering studies have provided three-dimensional structural details of the native neuronal porosome at sub-nanometer resolution, providing insights into the molecular mechanism of its function. The participation of several porosome proteins previously implicated in neurotransmission and neurological disorders, further attest to the crosstalk between porosome proteins and their coordinated involvement in release of neurotransmitter at the synapse.
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Affiliation(s)
- Akshata R Naik
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Kenneth T Lewis
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Bhanu P Jena
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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9
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Jena BP. 'Porosome' discovered nearly 20 years ago provides molecular insights into the kiss-and-run mechanism of cell secretion. J Cell Mol Med 2015; 19:1427-40. [PMID: 26033351 PMCID: PMC4511343 DOI: 10.1111/jcmm.12598] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 03/30/2015] [Indexed: 11/30/2022] Open
Abstract
Secretion is a fundamental cellular process in living organisms, from yeast to cells in humans. Since the 1950s, it was believed that secretory vesicles completely merged with the cell plasma membrane during secretion. While this may occur, the observation of partially empty vesicles in cells following secretion suggests the presence of an additional mechanism that allows partial discharge of intra-vesicular contents during secretion. This proposed mechanism requires the involvement of a plasma membrane structure called ‘porosome’, which serves to prevent the collapse of secretory vesicles, and to transiently fuse with the plasma membrane (Kiss-and-run), expel a portion of its contents and disengage. Porosomes are cup-shaped supramolecular lipoprotein structures at the cell plasma membrane ranging in size from 15 nm in neurons and astrocytes to 100–180 nm in endocrine and exocrine cells. Neuronal porosomes are composed of nearly 40 proteins. In comparison, the 120 nm nuclear pore complex is composed of >500 protein molecules. Elucidation of the porosome structure, its chemical composition and functional reconstitution into artificial lipid membrane, and the molecular assembly of membrane-associated t-SNARE and v-SNARE proteins in a ring or rosette complex resulting in the establishment of membrane continuity to form a fusion pore at the porosome base, has been demonstrated. Additionally, the molecular mechanism of secretory vesicle swelling, and its requirement for intra-vesicular content release during cell secretion has also been elucidated. Collectively, these observations provide a molecular understanding of cell secretion, resulting in a paradigm shift in our understanding of the secretory process.
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Affiliation(s)
- Bhanu P Jena
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
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10
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Lee JS, Wu Y, Skallos P, Fang J, Zhang X, Karnovsky A, Woods J, Stemmer PM, Liu M, Zhang K, Chen X. Proteomics analysis of rough endoplasmic reticulum in pancreatic beta cells. Proteomics 2015; 15:1508-11. [PMID: 25546123 PMCID: PMC4489703 DOI: 10.1002/pmic.201400345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 11/02/2014] [Accepted: 12/18/2014] [Indexed: 12/20/2022]
Abstract
Pancreatic beta cells have well-developed ER to accommodate for the massive production and secretion of insulin. ER homeostasis is vital for normal beta cell function. Perturbation of ER homeostasis contributes to beta cell dysfunction in both type 1 and type 2 diabetes. To systematically identify the molecular machinery responsible for proinsulin biogenesis and maintenance of beta cell ER homeostasis, a widely used mouse pancreatic beta cell line, MIN6 cell was used to purify rough ER. Two different purification schemes were utilized. In each experiment, the ER pellets were solubilized and analyzed by 1D SDS-PAGE coupled with HPLC-MS/MS. A total of 1467 proteins were identified in three experiments with ≥95% confidence, among which 1117 proteins were found in at least two separate experiments and 737 proteins found in all three experiments. GO analysis revealed a comprehensive profile of known and novel players responsible for proinsulin biogenesis and ER homeostasis. Further bioinformatics analysis also identified potential beta cell specific ER proteins as well as ER proteins present in the risk genetic loci of type 2 diabetes. This dataset defines a molecular environment in the ER for proinsulin synthesis, folding and export and laid a solid foundation for further characterizations of altered ER homeostasis under diabetes-causing conditions. All MS data have been deposited in the ProteomeXchange with identifier PXD001081 (http://proteomecentral.proteomexchange.org/dataset/PXD001081).
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Affiliation(s)
- Jin-sook Lee
- Department of Physiology, Wayne State University, Detroit, MI 48201
| | - Yanning Wu
- Department of Physiology, Wayne State University, Detroit, MI 48201
| | - Patracia Skallos
- Department of Physiology, Wayne State University, Detroit, MI 48201
| | - Jingye Fang
- Department of Physiology, Wayne State University, Detroit, MI 48201
| | - Xuebao Zhang
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201
| | - Alla Karnovsky
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109
| | - James Woods
- Department of Physiology, Wayne State University, Detroit, MI 48201
| | - Paul M. Stemmer
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201
| | - Ming Liu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201
| | - Xuequn Chen
- Department of Physiology, Wayne State University, Detroit, MI 48201
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11
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Rajagopal A, Kulkarni S, Lewis KT, Chen X, Maarouf A, Kelly CV, Taatjes DJ, Jena BP. Proteome of the insulin-secreting Min6 cell porosome complex: involvement of Hsp90 in its assembly and function. J Proteomics 2014; 114:83-92. [PMID: 25464371 DOI: 10.1016/j.jprot.2014.11.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/19/2014] [Accepted: 11/03/2014] [Indexed: 11/15/2022]
Abstract
UNLABELLED Porosomes are secretory portals located at the cell plasma membrane involved in the regulated release of intravesicular contents from cells. Porosomes have been immunoisolated from a number of cells including the exocrine pancreas and neurons, biochemically characterized, and functionally reconstituted into an artificial lipid membrane. In the current study, the proteome of the porosome complex in mouse insulinoma Min6 cells was determined, demonstrating among other proteins, the presence of 30 core proteins including the heat shock protein Hsp90. Half maximal inhibition of Hsp90 using the specific inhibitor 17-demethoxy-17-(2-prophenylamino) geldanamycin, results in the loss of proteins, including the calcium-transporting ATPase type 2C and the potassium channel subfamily K member 2 from the Min6 porosome. This loss of porosome proteins is reflected in the observed inhibition of glucose stimulated insulin release from Min6 cells exposed to the Hsp90 specific inhibitor. Results from the study implicate Hsp90 in the assembly and function of the porosome complex. BIOLOGICAL SIGNIFICANCE In the present study, the porosome proteome in the insulin-secreting mouse β-cell line Min6 has been determined. Nearly 30 core proteins including the heat shock protein Hsp90 are found to compose the Min6 porosome complex. Results from the study implicate Hsp90 in the assembly of the Min6 porosome. These new findings will facilitate understanding of the porosome assembly and its function in insulin secretion.
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Affiliation(s)
- Amulya Rajagopal
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Sanjana Kulkarni
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Kenneth T Lewis
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Xuequn Chen
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
| | - Abir Maarouf
- Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA
| | - Christopher V Kelly
- Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA
| | - Douglas J Taatjes
- Department of Pathology and Laboratory Medicine, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Bhanu P Jena
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA; Wayne State University, Department of Physics and Astronomy, Detroit, MI, USA.
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12
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Leabu M, Niculite CM. Porosome: a membrane microdomain acting as the universal secretory portal in exocytosis. Discoveries (Craiova) 2014; 2:e29. [PMID: 32309556 PMCID: PMC6919544 DOI: 10.15190/d.2014.21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 09/22/2014] [Accepted: 09/22/2014] [Indexed: 11/22/2022] Open
Abstract
Most, if not all, cells in the organism, at least in some period of their lifetime, secrete materials that are produced within the cell. Cell secretion is a phenomenon requiring membrane fusion at a specialized plasma membrane structure called the 'porosome,' which allows the material stored within secretory vesicles to be delivered to the cell's exterior environment. This is achieved when the secretory vesicles fuse at the base of the porosome complex, establishing a fusion pore or fluid continuity between the vesicle interior and the cell's exterior. Besides cell secretion, membrane fusion is necessary for intracellular membrane traffic and vesicular transport from one endomembrane bound structure to another. In addition to cell secretion, membrane fusion is necessary for intracellular membrane trafficking and vesicle transport from one intracellular membrane to another. We suggest that the debate about whether to use the term 'porosome' or 'fusion pore' to describe this process is unnecessary, since both of these terms are useful in describing aspects of the last event of cell secretion, namely exocytosis. In this review, we will summarize the information related to the discovery of the porosome, a universal secretory portal for exocytosis, and discuss porosome molecular organization and function. Finally, we will develop the notion that the porosome is a specialized plasma membrane microdomain.
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Affiliation(s)
- Mircea Leabu
- University of Medicine and Pharmacy "Carol Davila", and "Victor Babes" National Institute of Pathology, Bucharest, Romania
| | - Cristina Mariana Niculite
- University of Medicine and Pharmacy "Carol Davila", and "Victor Babes" National Institute of Pathology, Bucharest, Romania
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Lewis KT, Maddipati KR, Taatjes DJ, Jena BP. Neuronal porosome lipidome. J Cell Mol Med 2014; 18:1927-37. [PMID: 25224862 PMCID: PMC4244008 DOI: 10.1111/jcmm.12383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/02/2014] [Indexed: 12/05/2022] Open
Abstract
Cup-shaped lipoprotein structures called porosomes are the universal secretory portals at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intravesicular contents. In neurons, porosomes measure ∼15 nm and are comprised of nearly 40 proteins, among them SNAREs, ion channels, the Gαo G-protein and several structural proteins. Earlier studies report the interaction of specific lipids and their influence on SNAREs, ion channels and G-protein function. Our own studies demonstrate the requirement of cholesterol for the maintenance of neuronal porosome integrity, and the influence of lipids on SNARE complex assembly. In this study, to further understand the role of lipids on porosome structure-function, the lipid composition of isolated neuronal porosome was determined using mass spectrometry. Using lipid-binding assays, the affinity of porosome-associated syntaxin-1A to various lipids was determined. Our mass spectrometry results demonstrate the presence of phosphatidylinositol phosphates (PIP's) and phosphatidic acid (PA) among other lipids, and the enriched presence of ceramide (Cer), lysophosphatidylinositol phosphates (LPIP) and diacylglycerol (DAG). Lipid binding assays demonstrate the binding of neuronal porosome to cardiolipin, and confirm its association with PIP's and PA. The ability of exogenous PA to alter protein–protein interaction and neurotransmitter release is further demonstrated from the study.
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Affiliation(s)
- Kenneth T Lewis
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
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Jena BP. Neuronal Porosome-The Secretory Portal at the Nerve Terminal: It's Structure-Function, Composition, and Reconstitution. J Mol Struct 2014; 1073:187-195. [PMID: 26412873 PMCID: PMC4580341 DOI: 10.1016/j.molstruc.2014.04.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cup-shaped secretory portals at the cell plasma membrane called porosomes mediate secretion from cells. Membrane bound secretory vesicles transiently dock and fuse at the cytosolic compartment of the porosome base to expel intravesicular contents to the outside during cell secretion. In the past decade, the structure, isolation, composition, and functional reconstitution of the neuronal porosome complex has been accomplished providing a molecular understanding of its structure-function. Neuronal porosomes are 15 nm cup-shaped lipoprotein structures composed of nearly 40 proteins. Being a membrane-associated supramolecular complex has precluded determination of the atomic structure of the porosome. However recent studies using small-angle X-ray solution scattering (SAXS), provide at sub-nanometer resolution, the native 3D structure of the neuronal porosome complex associated with docked synaptic vesicle at the nerve terminal. Additionally, results from the SAXS study and earlier studies using atomic force microscopy, provide the possible molecular mechanism involved in porosome-mediated neurotransmitter release at the nerve terminal.
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Affiliation(s)
- Bhanu P. Jena
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
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Craciun C. Porosome in the Exocrine Pancreas: A Detailed EM Study suppressor. Discoveries (Craiova) 2014; 2:e23. [PMID: 32309552 PMCID: PMC6941546 DOI: 10.15190/d.2014.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A major question in cell biology that accumulation of partially empty vesicles in cells following secretion is seen, while it is believed that secretion occurs via the complete merger of secretory vesicles with the cell plasma membrane. This important question was solved nearly two decades ago, with the discovery of the Porosome. Porosomes are cup-shaped lipoprotein structures found at the plasma membrane of all cells. Secretory vesicles dock and transiently fuse at the porosome base to form a continuous channel or fusion pore to release the pressurized vesicle contents to the outside. In a decade-long study by our group, we carefully examined using electron microscopy, the detailed structure of the porosome complex in acinar cells of the exocrine pancreas. Besides conformation of earlier findings, our study provides in much greater detail, the in situ morphology of the porosome complex in the exocrine pancreas. The discovery of the detailed morphology of the exocrine pancreas porosome complex in my laboratory is one of the major highlights of my academic career spanning nearly 50 years. Results from our EM studies, reveal for the first time the presence of tethers or cables, which are likely t-SNAREs, present at the porosome base. These EM studies further demonstrate for the first time the docking of a single secretory vesicle or zymogen granule at the base of more than one porosome complex. Detailed spoke-like elements lining the porosome cup were also observed for the first time in these studies, greatly advancing our understanding of the molecular architecture and physiology of the porosome in the exocrine pancreas.
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Abstract
Macromolecular structures embedded in the cell plasma membrane called ‘porosomes’, are involved in the regulated fractional release of intravesicular contents from cells during secretion. Porosomes range in size from 15 nm in neurons and astrocytes to 100-180 nm in the exocrine pancreas and neuroendocrine cells. Porosomes have been isolated from a number of cells, and their morphology, composition, and functional reconstitution well documented. The 3D contour map of the assembly of proteins within the porosome complex, and its native X-ray solution structure at sub-nm resolution has also advanced. This understanding now provides a platform to address diseases that may result from secretory defects. Water and ion binding to mucin impart hydration, critical for regulating viscosity of the mucus in the airways epithelia. Appropriate viscosity is required for the movement of mucus by the underlying cilia. Hence secretion of more viscous mucus prevents its proper transport, resulting in chronic and fatal airways disease such as cystic fibrosis (CF). CF is caused by the malfunction of CF transmembrane conductance regulator (CFTR), a chloride channel transporter, resulting in viscous mucus in the airways. Studies in mice lacking functional CFTR secrete highly viscous mucous that adhered to the epithelium. Since CFTR is known to interact with the t-SNARE protein syntaxin-1A, and with the chloride channel CLC-3, which are also components of the porosome complex, the interactions between CFTR and the porosome complex in the mucin-secreting human airway epithelial cell line Calu-3 was hypothesized and tested. Results from the study demonstrate the presence of approximately 100 nm in size porosome complex composed of 34 proteins at the cell plasma membrane in Calu-3 cells, and the association of CFTR with the complex. In comparison, the nuclear pore complex measures 120 nm and is comprised of over 500 protein molecules. The involvement of CFTR in porosome-mediated mucin secretion is hypothesized, and is currently being tested.
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Affiliation(s)
- Bhanu P Jena
- Wayne State University School of Medicine, Department of Physiology, Detroit, MI, USA
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Wang H, Eckel RH. What are lipoproteins doing in the brain? Trends Endocrinol Metab 2014; 25:8-14. [PMID: 24189266 PMCID: PMC4062975 DOI: 10.1016/j.tem.2013.10.003] [Citation(s) in RCA: 152] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/30/2013] [Accepted: 10/02/2013] [Indexed: 12/25/2022]
Abstract
Lipoproteins in plasma transport lipids between tissues, however, only high-density lipoproteins (HDL) appear to traverse the blood-brain barrier (BBB); thus, lipoproteins found in the brain must be produced within the central nervous system. Apolipoproteins E (ApoE) and ApoJ are the most abundant apolipoproteins in the brain, are mostly synthesized by astrocytes, and are found on HDL. In the hippocampus and other brain regions, lipoproteins help to regulate neurobehavioral functions by processes that are lipoprotein receptor-mediated. Moreover, lipoproteins and their receptors also have roles in the regulation of body weight and energy balance, acting through lipoprotein lipase (LPL) and the low-density lipoprotein (LDL) receptor-related protein (LRP). Thus, understanding lipoproteins and their metabolism in the brain provides a new opportunity with potential therapeutic relevance.
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Affiliation(s)
- Hong Wang
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - Robert H Eckel
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
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18
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Taatjes DJ, Quinn AS, Rand JH, Jena BP. Atomic force microscopy: High resolution dynamic imaging of cellular and molecular structure in health and disease. J Cell Physiol 2013; 228:1949-55. [PMID: 23526453 DOI: 10.1002/jcp.24363] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 03/05/2013] [Indexed: 12/20/2022]
Abstract
The atomic force microscope (AFM), invented in 1986, and a member of the scanning probe family of microscopes, offers the unprecedented ability to image biological samples unfixed and in a hydrated environment at high resolution. This opens the possibility to investigate biological mechanisms temporally in a heretofore unattainable resolution. We have used AFM to investigate: (1) fundamental issues in cell biology (secretion) and, (2) the pathological basis of a human thrombotic disease, the antiphospholipid syndrome (APS). These studies have incorporated the imaging of live cells at nanometer resolution, leading to discovery of the "porosome," the universal secretory portal in cells, and a molecular understanding of membrane fusion from imaging the interaction and assembly of proteins between opposing lipid membranes. Similarly, the development of an in vitro simulacrum for investigating the molecular interactions between proteins and lipids has helped define an etiological explanation for APS. The prime importance of AFM in the success of these investigations will be presented in this manuscript, as well as a discussion of the limitations of this technique for the study of biomedical samples.
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Affiliation(s)
- Douglas J Taatjes
- Department of Pathology and Microscopy Imaging Center, College of Medicine, University of Vermont, Burlington, VT 05405, USA.
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Hou X, Lewis KT, Wu Q, Wang S, Chen X, Flack A, Mao G, Taatjes DJ, Sun F, Jena BP. Proteome of the porosome complex in human airway epithelia: interaction with the cystic fibrosis transmembrane conductance regulator (CFTR). J Proteomics 2013; 96:82-91. [PMID: 24220302 DOI: 10.1016/j.jprot.2013.10.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/20/2013] [Accepted: 10/31/2013] [Indexed: 01/11/2023]
Abstract
UNLABELLED The surface of the airways is coated with a thin film of mucus composed primarily of mucin, which is under continuous motion via ciliary action. Mucin not only serves to lubricate the airways epithelia, but also functions as a trap for foreign particles and pathogens, thereby assisting in keeping the airways clean and free of particulate matter and infections. Altered mucin secretion especially increased mucin viscosity, results in mucin stagnation due to the inability of the cilia to propel them, leading to infections and diseases such as cystic fibrosis (CF). Since porosomes have been demonstrated to be the secretory portals at the cell plasma membrane in cells, their presence, structure, and composition in the mucin-secreting human airway epithelial cell line Calu-3 expressing CF transmembrane receptor (CFTR), were investigated. Atomic force microscopy (AFM) of Calu-3 cells demonstrates the presence of approximately 100nm in diameter porosome openings at the plasma membrane surface. Electron microscopy confirms the AFM results, and tandem mass spectrometry and immunoanalysis performed on isolated Calu-3 porosomes, reveal the association of CFTR with the porosome complex. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease. BIOLOGICAL SIGNIFICANCE In the present study, the porosome proteome in human airway epithelia has been determined. The interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) and the porosome complex in the human airway epithelia is further demonstrated. The possible regulation by CFTR on the quality of mucus secretion via the porosome complex at the cell plasma membrane is hypothesized. These new findings will facilitate understanding of CFTR-porosome interactions influencing mucous secretion, and provide critical insights into the etiology of CF disease.
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Affiliation(s)
- Xia Hou
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Kenneth T Lewis
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Qingtian Wu
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Sunxi Wang
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Amanda Flack
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Guangzhao Mao
- Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA
| | - Douglas J Taatjes
- Department of Pathology, Microscopy Imaging Center, University of Vermont College of Medicine, Burlington, VT 05405, USA
| | - Fei Sun
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA
| | - Bhanu P Jena
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA; Department of Chemical Engineering & Materials Science, College of Engineering, Wayne State University, MI 48202, USA.
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Kovari LC, Brunzelle JS, Lewis KT, Cho WJ, Lee JS, Taatjes DJ, Jena BP. X-ray solution structure of the native neuronal porosome-synaptic vesicle complex: Implication in neurotransmitter release. Micron 2013; 56:37-43. [PMID: 24176623 DOI: 10.1016/j.micron.2013.10.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 09/29/2013] [Accepted: 10/02/2013] [Indexed: 11/30/2022]
Abstract
Nanoportals at the cell plasma membrane called porosomes, mediate secretion from cells. In neurons porosomes are 15 nm cup-shaped lipoprotein structure composed of nearly 40 proteins. The size and complexity of the porosome has precluded determination of its atomic structure. Here we report at nanometer resolution the native 3D structure of the neuronal porosome-synaptic vesicle complex within isolated nerve terminals using small-angle X-ray solution scattering. In addition to furthering our understanding of the porosome structure, results from the study suggests the molecular mechanism involved in neurotransmitter release at the nerve terminal.
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Affiliation(s)
- Ladislau C Kovari
- Wayne State University School of Medicine, Department of Biochemistry and Molecular Biology, Detroit, MI, USA
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Hammel I, Meilijson I. Function suggests nano-structure: towards a unified theory for secretion rate, a statistical mechanics approach. J R Soc Interface 2013; 10:20130640. [PMID: 24004560 DOI: 10.1098/rsif.2013.0640] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The inventory of secretory granules along the plasma membrane can be viewed as maintained in two restricted compartments. The release-ready pool represents docked granules available for an initial stage of fast, immediate secretion, followed by a second stage of granule set-aside secretion pool, with significantly slower rate. Transmission electron microscopy ultra-structural investigations correlated with electrophysiological techniques and mathematical modelling have allowed the categorization of these secretory vesicle compartments, in which vesicles can be in various states of secretory competence. Using the above-mentioned approaches, the kinetics of single vesicle exocytosis can be worked out. The ultra-fast kinetics, explored in this study, represents the immediately available release-ready pool, in which granules bound to the plasma membrane are exocytosed upon Ca(2+) influx at the SNARE rosette at the base of porosomes. Formalizing Dodge and Rahamimoff findings on the effect of calcium concentration and incorporating the effect of SNARE transient rosette size, we postulate that secretion rate (rate), the number (X) of intracellular calcium ions available for fusion, calcium capacity (0 ≤ M ≤ 5) and the fusion nano-machine size (as measured by the SNARE rosette size K) satisfy the parsimonious M-K relation rate ≈ C × [Ca(2+)](min(X,M))e(-K/2).
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Affiliation(s)
- Ilan Hammel
- Sackler Faculty of Medicine, Department of Pathology, Tel Aviv University, Tel Aviv 6997801, Israel.
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The protective effect of myo-inositol on hippocamal cell loss and structural alterations in neurons and synapses triggered by kainic acid-induced status epilepticus. Cell Mol Neurobiol 2013; 33:659-71. [PMID: 23568659 DOI: 10.1007/s10571-013-9930-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/18/2013] [Indexed: 02/02/2023]
Abstract
It is known that myo-inositol pretreatment attenuates the seizure severity and several biochemical changes provoked by experimentally induced status epilepticus. However, it remains unidentified whether such properties of myo-inositol influence the structure of epileptic brain. In the present light and electron microscopic research we elucidate if pretreatment with myo-inositol has positive effect on hippocampal cell loss, and cell and synapses damage provoked by kainic acid-induced status epilepticus. Adult male Wistar rats were treated with (i) saline, (ii) saline + kainic acid, (iii) myo-inositol + kainic acid. Assessment of cell loss at 2, 14, and 30 days after treatment demonstrate cytoprotective effect of myo-inositol in CA1 and CA3 areas. It was strongly expressed in pyramidal layer of CA1, radial and oriental layers of CA3 and in less degree-in other layers of both fields. Ultrastructural alterations were described in CA1, 14 days after treatment. The structure of neurons, synapses, and porosomes are well preserved in the rats pretreated with myo-inositol in comparing with rats treated with only kainic acid.
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