1
|
Yue X, Qian Y, Zhu L, Gim B, Bao M, Jia J, Jing S, Wang Y, Tan C, Bottanelli F, Ziltener P, Choi S, Hao P, Lee I. ACBD3 modulates KDEL receptor interaction with PKA for its trafficking via tubulovesicular carrier. BMC Biol 2021; 19:194. [PMID: 34493279 PMCID: PMC8424950 DOI: 10.1186/s12915-021-01137-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 08/30/2021] [Indexed: 11/10/2022] Open
Abstract
Background KDEL receptor helps establish cellular equilibrium in the early secretory pathway by recycling leaked ER-chaperones to the ER during secretion of newly synthesized proteins. Studies have also shown that KDEL receptor may function as a signaling protein that orchestrates membrane flux through the secretory pathway. We have recently shown that KDEL receptor is also a cell surface receptor, which undergoes highly complex itinerary between trans-Golgi network and the plasma membranes via clathrin-mediated transport carriers. Ironically, however, it is still largely unknown how KDEL receptor is distributed to the Golgi at steady state, since its initial discovery in late 1980s. Results We used a proximity-based in vivo tagging strategy to further dissect mechanisms of KDEL receptor trafficking. Our new results reveal that ACBD3 may be a key protein that regulates KDEL receptor trafficking via modulation of Arf1-dependent tubule formation. We demonstrate that ACBD3 directly interact with KDEL receptor and form a functionally distinct protein complex in ArfGAPs-independent manner. Depletion of ACBD3 results in re-localization of KDEL receptor to the ER by inducing accelerated retrograde trafficking of KDEL receptor. Importantly, this is caused by specifically altering KDEL receptor interaction with Protein Kinase A and Arf1/ArfGAP1, eventually leading to increased Arf1-GTP-dependent tubular carrier formation at the Golgi. Conclusions These results suggest that ACBD3 may function as a negative regulator of PKA activity on KDEL receptor, thereby restricting its retrograde trafficking in the absence of KDEL ligand binding. Since ACBD3 was originally identified as PAP7, a PBR/PKA-interacting protein at the Golgi/mitochondria, we propose that Golgi-localization of KDEL receptor is likely to be controlled by its interaction with ACBD3/PKA complex at steady state, providing a novel insight for establishment of cellular homeostasis in the early secretory pathway. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01137-7.
Collapse
Affiliation(s)
- Xihua Yue
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Yi Qian
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Lianhui Zhu
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Bopil Gim
- School of Physical Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Mengjing Bao
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Jie Jia
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shuaiyang Jing
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yijing Wang
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chuanting Tan
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Francesca Bottanelli
- Institut für Biochemie, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Pascal Ziltener
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Sunkyu Choi
- Proteomics Core, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Piliang Hao
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Intaek Lee
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China. .,Shanghai Institute for Advanced Immunochemical Studies, Shanghai, China.
| |
Collapse
|
2
|
Hendrickx DM, Garcia P, Ashrafi A, Sciortino A, Schmit KJ, Kollmus H, Nicot N, Kaoma T, Vallar L, Buttini M, Glaab E. A New Synuclein-Transgenic Mouse Model for Early Parkinson's Reveals Molecular Features of Preclinical Disease. Mol Neurobiol 2021; 58:576-602. [PMID: 32997293 PMCID: PMC8219584 DOI: 10.1007/s12035-020-02085-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/21/2020] [Indexed: 12/14/2022]
Abstract
Understanding Parkinson's disease (PD), in particular in its earliest phases, is important for diagnosis and treatment. However, human brain samples are collected post-mortem, reflecting mainly end-stage disease. Because brain samples of mouse models can be collected at any stage of the disease process, they are useful in investigating PD progression. Here, we compare ventral midbrain transcriptomics profiles from α-synuclein transgenic mice with a progressive, early PD-like striatal neurodegeneration across different ages using pathway, gene set, and network analysis methods. Our study uncovers statistically significant altered genes across ages and between genotypes with known, suspected, or unknown function in PD pathogenesis and key pathways associated with disease progression. Among those are genotype-dependent alterations associated with synaptic plasticity and neurotransmission, as well as mitochondria-related genes and dysregulation of lipid metabolism. Age-dependent changes were among others observed in neuronal and synaptic activity, calcium homeostasis, and membrane receptor signaling pathways, many of which linked to G-protein coupled receptors. Most importantly, most changes occurred before neurodegeneration was detected in this model, which points to a sequence of gene expression events that may be relevant for disease initiation and progression. It is tempting to speculate that molecular changes similar to those changes observed in our model happen in midbrain dopaminergic neurons before they start to degenerate. In other words, we believe we have uncovered molecular changes that accompany the progression from preclinical to early PD.
Collapse
Affiliation(s)
- Diana M. Hendrickx
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
| | - Pierre Garcia
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
- Laboratoire National de Santé (LNS), Neuropathology Unit, Dudelange, Luxembourg
| | - Amer Ashrafi
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
- Present Address: Division of Immunology, Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA USA
| | - Alessia Sciortino
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
| | - Kristopher J. Schmit
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
| | - Heike Kollmus
- Department of Infection Genetics, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Nathalie Nicot
- Quantitative Biology Unit, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Tony Kaoma
- Department of Oncology, Luxembourg Institute of Health, Strassen, Luxembourg
| | - Laurent Vallar
- Genomics Research Unit, Luxembourg Institute of Health, Luxembourg, Luxembourg
| | - Manuel Buttini
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
| | - Enrico Glaab
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belvaux, Luxembourg
| |
Collapse
|
3
|
Tóth G, Gardai SJ, Zago W, Bertoncini CW, Cremades N, Roy SL, Tambe MA, Rochet JC, Galvagnion C, Skibinski G, Finkbeiner S, Bova M, Regnstrom K, Chiou SS, Johnston J, Callaway K, Anderson JP, Jobling MF, Buell AK, Yednock TA, Knowles TPJ, Vendruscolo M, Christodoulou J, Dobson CM, Schenk D, McConlogue L. Targeting the intrinsically disordered structural ensemble of α-synuclein by small molecules as a potential therapeutic strategy for Parkinson's disease. PLoS One 2014; 9:e87133. [PMID: 24551051 PMCID: PMC3925190 DOI: 10.1371/journal.pone.0087133] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/19/2013] [Indexed: 12/22/2022] Open
Abstract
The misfolding of intrinsically disordered proteins such as α-synuclein, tau and the Aβ peptide has been associated with many highly debilitating neurodegenerative syndromes including Parkinson’s and Alzheimer’s diseases. Therapeutic targeting of the monomeric state of such intrinsically disordered proteins by small molecules has, however, been a major challenge because of their heterogeneous conformational properties. We show here that a combination of computational and experimental techniques has led to the identification of a drug-like phenyl-sulfonamide compound (ELN484228), that targets α-synuclein, a key protein in Parkinson’s disease. We found that this compound has substantial biological activity in cellular models of α-synuclein-mediated dysfunction, including rescue of α-synuclein-induced disruption of vesicle trafficking and dopaminergic neuronal loss and neurite retraction most likely by reducing the amount of α-synuclein targeted to sites of vesicle mobilization such as the synapse in neurons or the site of bead engulfment in microglial cells. These results indicate that targeting α-synuclein by small molecules represents a promising approach to the development of therapeutic treatments of Parkinson’s disease and related conditions.
Collapse
Affiliation(s)
- Gergely Tóth
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- Elan Pharmaceuticals, South San Francisco, California, United States of America
- * E-mail: (LM); (GT); (MV); (DS); (CMD)
| | - Shyra J. Gardai
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Wagner Zago
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Carlos W. Bertoncini
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- SEDIPFAR (Servicio De Descubrimiento, Diseño Y Desarrollo Pre-Clínico De Fármacos De La Argentina) drug discovery platform, Universidad Nacional de Rosario, Rosario, Argentina
| | - Nunilo Cremades
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Susan L. Roy
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Mitali A. Tambe
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Jean-Christophe Rochet
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, United States of America
| | - Celine Galvagnion
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Gaia Skibinski
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Taube-Koret Center for Neurodegenerative Disease Research, The Consortium for Frontotemporal Dementia Research, and The Hellman Family Foundation Program for Alzheimer’s Disease Research, San Francisco, California, United States of America
| | - Steven Finkbeiner
- Gladstone Institute of Neurological Disease, San Francisco, California, United States of America
- Taube-Koret Center for Neurodegenerative Disease Research, The Consortium for Frontotemporal Dementia Research, and The Hellman Family Foundation Program for Alzheimer’s Disease Research, San Francisco, California, United States of America
- Departments of Neurology and Physiology, UCSF, San Francisco, California, United States of America
| | - Michael Bova
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Karin Regnstrom
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - San-San Chiou
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Jennifer Johnston
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Kari Callaway
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - John P. Anderson
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Michael F. Jobling
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | - Alexander K. Buell
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Ted A. Yednock
- Elan Pharmaceuticals, South San Francisco, California, United States of America
| | | | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (LM); (GT); (MV); (DS); (CMD)
| | - John Christodoulou
- Department of Structural & Molecular Biology, University College London, London, United Kingdom
| | - Christopher M. Dobson
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail: (LM); (GT); (MV); (DS); (CMD)
| | - Dale Schenk
- Elan Pharmaceuticals, South San Francisco, California, United States of America
- * E-mail: (LM); (GT); (MV); (DS); (CMD)
| | - Lisa McConlogue
- Elan Pharmaceuticals, South San Francisco, California, United States of America
- * E-mail: (LM); (GT); (MV); (DS); (CMD)
| |
Collapse
|
4
|
Gardai SJ, Mao W, Schüle B, Babcock M, Schoebel S, Lorenzana C, Alexander J, Kim S, Glick H, Hilton K, Fitzgerald JK, Buttini M, Chiou SS, McConlogue L, Anderson JP, Schenk DB, Bard F, Langston JW, Yednock T, Johnston JA. Elevated alpha-synuclein impairs innate immune cell function and provides a potential peripheral biomarker for Parkinson's disease. PLoS One 2013; 8:e71634. [PMID: 24058406 PMCID: PMC3751933 DOI: 10.1371/journal.pone.0071634] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 07/01/2013] [Indexed: 12/14/2022] Open
Abstract
Alpha-synuclein protein is strongly implicated in the pathogenesis Parkinson's disease. Increased expression of α-synuclein due to genetic multiplication or point mutations leads to early onset disease. While α-synuclein is known to modulate membrane vesicle dynamics, it is not clear if this activity is involved in the pathogenic process or if measurable physiological effects of α-synuclein over-expression or mutation exist in vivo. Macrophages and microglia isolated from BAC α-synuclein transgenic mice, which overexpress α-synuclein under regulation of its own promoter, express α-synuclein and exhibit impaired cytokine release and phagocytosis. These processes were affected in vivo as well, both in peritoneal macrophages and microglia in the CNS. Extending these findings to humans, we found similar results with monocytes and fibroblasts isolated from idiopathic or familial Parkinson's disease patients compared to age-matched controls. In summary, this paper provides 1) a new animal model to measure α-synuclein dysfunction; 2) a cellular system to measure synchronized mobilization of α-synuclein and its functional interactions; 3) observations regarding a potential role for innate immune cell function in the development and progression of Parkinson's disease and other human synucleinopathies; 4) putative peripheral biomarkers to study and track these processes in human subjects. While altered neuronal function is a primary issue in PD, the widespread consequence of abnormal α-synuclein expression in other cell types, including immune cells, could play an important role in the neurodegenerative progression of PD and other synucleinopathies. Moreover, increased α-synuclein and altered phagocytosis may provide a useful biomarker for human PD.
Collapse
Affiliation(s)
- Shyra J. Gardai
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
- * E-mail:
| | - Wenxian Mao
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Birgitt Schüle
- The Parkinson's Institute, Sunnyvale, California, United States of America
| | - Michael Babcock
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Sue Schoebel
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Carlos Lorenzana
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Jeff Alexander
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Sam Kim
- The Parkinson's Institute, Sunnyvale, California, United States of America
| | - Heather Glick
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Kathryn Hilton
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - J. Kent Fitzgerald
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Manuel Buttini
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - San-San Chiou
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Lisa McConlogue
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - John P. Anderson
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Dale B. Schenk
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Frederique Bard
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | | | - Ted Yednock
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| | - Jennifer A. Johnston
- Elan Pharmaceuticals, Research, South San Francisco, California, United States of America
| |
Collapse
|
5
|
Abstract
Adrenal gonadal, placental and brain mitochondria contain several steroidogenic enzymes, notably the cholesterol side chain cleavage enzyme, P450scc, which is the enzymatic rate-limiting step in steroidogenesis which determines cellular steroidogenic capacity. Even before this step, the access of cholesterol to this enzyme system is both rate-limiting and the site of acute regulation via the steroidogenic acute regulatory protein (StAR) which interacts with a complex multi-component 'transduceosome' on the outer mitochondrial membrane (OMM). The components of the transduceosome include the 18 kDa translocator protein (TSPO), the voltage-dependent anion channel (VDAC-1), TSPO-associated protein 7 (PAP7, ACBD3 for acyl-CoA-binding-domain 3), and protein kinase A regulatory subunit 1α (PKAR1A). The precise fashion in which these proteins interact and move cholesterol from the OMM to P450scc, and the means by which cholesterol is loaded into the OMM, remain unclear. Human deficiency diseases have been described for StAR and for P450scc. Mitochondria also contain several 'downstream' steroidogenic enzymes.
Collapse
Affiliation(s)
- Vassilios Papadopoulos
- The Research Institute of the McGill University Health Centre, Department of Medicine, McGill University, Montreal, Quebec H3G 1A4, Canada.
| | | |
Collapse
|
6
|
Midzak A, Rone M, Aghazadeh Y, Culty M, Papadopoulos V. Mitochondrial protein import and the genesis of steroidogenic mitochondria. Mol Cell Endocrinol 2011; 336:70-9. [PMID: 21147195 PMCID: PMC3057322 DOI: 10.1016/j.mce.2010.12.007] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 12/03/2010] [Accepted: 12/05/2010] [Indexed: 11/23/2022]
Abstract
The principal site of regulation of steroid hormone biosynthesis is the transfer of cholesterol from the outer to inner mitochondrial membrane. Hormonal stimulation of steroidogenic cells promotes this mitochondrial lipid import through a multi-protein complex, termed the transduceosome, spanning the two membranes. The transduceosome complex is assembled from multiple proteins, such as the steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and requires their targeting to the mitochondria for transduceosome function. The vast majority of mitochondrial proteins, including those participating in cholesterol import, are encoded in the nucleus. Their subsequent mitochondrial incorporation is performed through a series of protein import machineries located in the outer and inner mitochondrial membranes. Here we review our current knowledge of the mitochondrial cholesterol import machinery of the transduceosome. This is complemented with descriptions of mitochondrial protein import machineries and mechanisms by which these machineries assemble the transduceosome in steroidogenic mitochondria.
Collapse
Affiliation(s)
- Andrew Midzak
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Malena Rone
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Yassaman Aghazadeh
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Martine Culty
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, H3G 1A4, Canada
| | - Vassilios Papadopoulos
- Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Medicine, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1A4, Canada
- Correspondence at The Research Institute of the McGill University Health Center, Montreal General Hospital, 1650 Cedar Avenue, C10-148, Montreal, Quebec H3G 1A4, Canada. Tel: 514-934-1934 ext. 44580; Fax: 514-934-8261;
| |
Collapse
|
7
|
Acyl-coenzyme A binding domain containing 3 (ACBD3; PAP7; GCP60): an emerging signaling molecule. Prog Lipid Res 2010; 49:218-34. [PMID: 20043945 DOI: 10.1016/j.plipres.2009.12.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Golgi body-mediated signaling has been linked to its fragmentation and regeneration during the mitotic cycle of the cell. During this process, Golgi-resident proteins are released to the cytosol and interact with other signaling molecules to regulate various cellular processes. Acyl-coenzyme A binding domain containing 3 protein (ACBD3) is a Golgi protein involved in several signaling events. ACBD3 protein was previously known as peripheral-type benzodiazepine receptor and cAMP-dependent protein kinase associated protein 7 (PAP7), Golgi complex-associated protein of 60kDa (GCP60), Golgi complex-associated protein 1 (GOCAP1), and Golgi phosphoprotein 1 (GOLPH1). In this review, we present the gene ontology of ACBD3, its relations to other Acyl-coenzyme A binding domain containing (ACBD) proteins, and its biological function in steroidogenesis, apoptosis, neurogenesis, and embryogenesis. We also discuss the role of ACBD3 in asymmetric cell division and cancer. New findings about ACBD3 may help understand this newly characterized signaling molecule and stimulate further research into its role in molecular endocrinology, neurology, and stem cell biology.
Collapse
|
8
|
Papadopoulos V, Liu J, Culty M. Is there a mitochondrial signaling complex facilitating cholesterol import? Mol Cell Endocrinol 2007; 265-266:59-64. [PMID: 17280776 DOI: 10.1016/j.mce.2006.12.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cholesterol transport into mitochondria is the rate-determining and hormone-sensitive step in steroid biosynthesis. During the last few years two proteins were shown to be critical for this process: the mitochondrial translocator protein, previously known as peripheral-type benzodiazepine receptor, and the steroidogenic acute regulatory protein. In this manuscript we review evidence suggesting that these two proteins functionally interact to facilitate cholesterol transport and may be part of a larger multimeric mitochondrial complex of proteins assembled to facilitate the hormone-induced cholesterol transfer into mitochondria. This complex might include proteins such as the mitochondrial voltage-dependent anion channel, the translocator protein-associated protein PAP7 which also functions as an A kinase anchor protein that binds and brings into the complex the regulatory subunit Ialpha of the cAMP-dependent protein kinase.
Collapse
Affiliation(s)
- Vassilios Papadopoulos
- Department of Biochemistry & Molecular and Cellular Biology, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20057, USA.
| | | | | |
Collapse
|
9
|
Liu J, Rone MB, Papadopoulos V. Protein-Protein Interactions Mediate Mitochondrial Cholesterol Transport and Steroid Biosynthesis. J Biol Chem 2006; 281:38879-93. [PMID: 17050526 DOI: 10.1074/jbc.m608820200] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Transport of cholesterol into the mitochondria is the rate-determining, hormone-sensitive step in steroid biosynthesis. Here we report that the mechanism underlying mitochondrial cholesterol transport involves the formation of a macromolecular signaling complex composed of the outer mitochondrial membrane translocator protein (TSPO), previously known as peripheral-type benzodiazepine receptor; the TSPO-associated protein PAP7, which binds and brings to mitochondria the regulatory subunit RIalpha of the cAMP-dependent protein kinase (PKARIalpha); and the hormone-induced PKA substrate, steroidogenic acute regulatory protein (StAR). Hormone treatment of MA-10 Leydig cells induced the co-localization of TSPO, PAP7, PKARIalpha, and StAR in mitochondria, visualized by confocal microscopy, and the formation in living cells of a high molecular weight multimeric complex identified using photoactivable amino acids. The hormone-induced recruitment of exogenous TSPO in this complex was found to parallel the increased presence of 7-azi-5alpha-cholestan-3beta-ol in the samples. Co-expression of Tspo, Pap7, PkarIalpha, and Star genes resulted in the stimulation of steroid formation in both steroidogenic MA-10 and non-steroidogenic COS-F2-130 cells that were engineered to metabolize cholesterol. Disruption of these protein-protein interactions and specifically the PKARIalpha-PAP7 and PAP7-TSPO interactions, using PAP7 mutants where the N0 area homologous to dual A-kinase-anchoring protein-1 or the acyl-CoA signature motif were deleted or using the peptide Ht31 known to disrupt the anchoring of PKA, inhibited both basal and hormone-induced steroidogenesis. These results suggest that the initiation of cAMP-induced protein-protein interactions results in the formation of a multivalent scaffold in the outer mitochondrial membrane that mediates the effect of hormones on mitochondrial cholesterol transport and steroidogenesis.
Collapse
Affiliation(s)
- Jun Liu
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, D. C. 20057, USA
| | | | | |
Collapse
|
10
|
Sbodio JI, Hicks SW, Simon D, Machamer CE. GCP60 preferentially interacts with a caspase-generated golgin-160 fragment. J Biol Chem 2006; 281:27924-31. [PMID: 16870622 DOI: 10.1074/jbc.m603276200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Golgin-160, a ubiquitous protein in vertebrates, localizes to the cytoplasmic face of the Golgi complex. Golgin-160 has a large coiled-coil C-terminal domain and a non-coiled-coil N-terminal ("head") domain. The head domain contains important motifs, including a nuclear localization signal, a Golgi targeting domain, and three aspartates that are recognized by caspases during apoptosis. Some of the caspase cleavage products accumulate in the nucleus when overexpressed. Expression of a non-cleavable form of golgin-160 impairs apoptosis induced by some pro-apoptotic stimuli; thus cleavage of golgin-160 appears to play a role in apoptotic signaling. We used a yeast two-hybrid assay to screen for interactors of the golgin-160 head and identified GCP60 (Golgi complex-associated protein of 60 kDa). Further analysis demonstrated that GCP60 interacts preferentially with one of the golgin-160 caspase cleavage fragments (residues 140-311). This strong interaction prevented the golgin-160 fragment from accumulating in the nucleus when this fragment and GCP60 were overexpressed. In addition, cells overexpressing GCP60 were more sensitive to apoptosis induced by staurosporine, suggesting that nuclear-localized golgin-160-(140-311) might promote cell survival. Our results suggest a potential mechanism for regulating the nuclear translocation and potential functions of golgin-160 fragments.
Collapse
Affiliation(s)
- Juan I Sbodio
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | | | | | |
Collapse
|
11
|
Lacapère JJ, Papadopoulos V. Peripheral-type benzodiazepine receptor: structure and function of a cholesterol-binding protein in steroid and bile acid biosynthesis. Steroids 2003; 68:569-85. [PMID: 12957662 DOI: 10.1016/s0039-128x(03)00101-6] [Citation(s) in RCA: 252] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cholesterol transport from the outer to the inner mitochondrial membrane is the rate-determining step in steroid and bile acid biosyntheses. Biochemical, pharmacological and molecular studies have demonstrated that the peripheral-type benzodiazepine receptor (PBR) is a five transmembrane domain mitochondrial protein involved in the regulation of cholesterol transport. PBR gene disruption in Leydig cells completely blocked cholesterol transport into mitochondria and steroid formation, while PBR expression in bacteria, devoid of endogenous PBR and cholesterol, induced cholesterol uptake and transport. Molecular modeling of PBR suggested that cholesterol might cross the membrane through the five helices of the receptor and that synthetic and endogenous ligands might bind to common sites in the cytoplasmic loops. A cholesterol recognition/interaction amino acid consensus (CRAC) sequence in the cytoplasmic carboxy-terminus of the PBR was identified by mutagenesis studies. In vitro reconstitution of PBR into proteoliposomes demonstrated that PBR binds both drug ligands and cholesterol with high affinity. In vivo polymeric forms of PBR were observed and polymer formation was reproduced in vitro, using recombinant PBR protein reconstituted into proteoliposomes, associated with an increase in drug ligand binding and reduction of cholesterol-binding capacity. This suggests that the various polymeric states of PBR might be part of a cycle mediating cholesterol uptake and release into the mitochondria, with PBR functioning as a cholesterol exchanger against steroid product(s) arising from cytochrome P450 action. Taking into account the widespread presence of PBR in many tissues, a more general role of PBR in intracellular cholesterol transport and compartmentalization might be considered.
Collapse
Affiliation(s)
- Jean Jacques Lacapère
- Unité INSERM U410, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, 75870 Paris Cedex 18, France.
| | | |
Collapse
|
12
|
Abstract
Spatial regulation of protein kinase A (PKA) is accomplished by its sequestration via A-kinase anchor proteins (AKAPs). PKA activity is critical for mammalian oocyte development, suggesting that PKA must be appropriately positioned in these large cells. A screen for AKAPs in oocytes identified AKAP7gamma, an AKAP originally found in pancreas. Yeast two-hybrid analysis and co-immunoprecipitation studies showed that AKAP7gamma bound the type I PKA regulatory subunit (RI) and that the RI-binding domain overlapped the previously identified type II PKA regulatory subunit (RII) binding domain. Overexpressed AKAP7gamma localized to the nuclei of HEK 293 cells via a nuclear localization signal. In addition, endogenous AKAP7gamma protein was found in both the nucleus and cytoplasm of oocytes. This work identifies AKAP7gamma as the first nuclear AKAP to bind RI and suggests that AKAP7gamma may be responsible for positioning PKA via RI and/or RII to regulate PKA-mediated gene transcription in both somatic cells and oocytes.
Collapse
Affiliation(s)
- Rebecca L Brown
- Center for Research on Reproduction and Women's Health, Department of Obstetrics and Gynecology, University of Pennsylvania, Rm. 1312 BRB II/III, 421 Curie Blvd., Philadelphia, PA 19104-6142, USA
| | | | | | | |
Collapse
|
13
|
Liu J, Li H, Papadopoulos V. PAP7, a PBR/PKA-RIalpha-associated protein: a new element in the relay of the hormonal induction of steroidogenesis. J Steroid Biochem Mol Biol 2003; 85:275-83. [PMID: 12943713 DOI: 10.1016/s0960-0760(03)00213-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The precise mechanism by which the hormone-induced minimal cAMP levels act at the mitochondria to activate cholesterol transport and steroid synthesis is unknown. We propose that this mechanism involves a macromolecular signaling complex where a newly identified peripheral-type benzodiazepine receptor (PBR)-associated protein (PAP7) binds the regulatory subunit RIalpha of the cAMP-dependent protein kinase A (PKA), thus allowing for local efficient catalytic activation and phosphorylation of the substrate steroidogenesis acute regulatory protein (StAR), leading to cholesterol transfer from the low affinity StAR to the high affinity PBR cholesterol binding protein. The mouse and human PAP7 proteins were cloned, their genomic organization and chromosomal localization characterized, their tissue distribution evaluated and subcellular localization defined. PAP7 is highly expressed in steroidogenic tissues, where it follows the pattern of PKA-RIalpha expression and data from a human adrenal disease suggest that it participates in PKA-RIalpha-mediated tumorigenesis and hormone-independent hypercortisolism. PAP7 is localized in the Golgi and mitochondria and inhibition of PAP7 expression results in reduced hormone-induced cholesterol transport into mitochondria and decreased steroid formation. Taken together, these data suggest that PAP7 functions as an A-kinase anchoring protein (AKAP) critical in the cAMP-dependent steroid formation.
Collapse
Affiliation(s)
- Jun Liu
- Division of Hormone Research, Department of Cell Biology, Georgetown University Medical Center, 3900 Reservoir Road NW, Washington, DC 20057, USA
| | | | | |
Collapse
|