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He Z, Xie L, Liu J, Wei X, Zhang W, Mei Z. Novel insight into the role of A-kinase anchoring proteins (AKAPs) in ischemic stroke and therapeutic potentials. Biomed Pharmacother 2024; 175:116715. [PMID: 38739993 DOI: 10.1016/j.biopha.2024.116715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/03/2024] [Accepted: 05/06/2024] [Indexed: 05/16/2024] Open
Abstract
Ischemic stroke, a devastating disease associated with high mortality and disability worldwide, has emerged as an urgent public health issue. A-kinase anchoring proteins (AKAPs) are a group of signal-organizing molecules that compartmentalize and anchor a wide range of receptors and effector proteins and have a major role in stabilizing mitochondrial function and promoting neurodevelopmental development in the central nervous system (CNS). Growing evidence suggests that dysregulation of AKAPs expression and activity is closely associated with oxidative stress, ion disorder, mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in ischemic stroke. However, the underlying mechanisms remain inadequately understood. This review provides a comprehensive overview of the composition and structure of A-kinase anchoring protein (AKAP) family members, emphasizing their physiological functions in the CNS. We explored in depth the molecular and cellular mechanisms of AKAP complexes in the pathological progression and risk factors of ischemic stroke, including hypertension, hyperglycemia, lipid metabolism disorders, and atrial fibrillation. Herein, we highlight the potential of AKAP complexes as a pharmacological target against ischemic stroke in the hope of inspiring translational research and innovative clinical approaches.
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Affiliation(s)
- Ziyu He
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Letian Xie
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Jiyong Liu
- Hunan Provincial Key Laboratory of Traditional Chinese Medicine Diagnostics, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Xuan Wei
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Wenli Zhang
- School of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China.
| | - Zhigang Mei
- Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese Medicine and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan 410208, China; Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, College of Medicine and Health Sciences, China Three Gorges University, Yichang, Hubei 443002, China.
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2
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Gambaryan S, Mohagaonkar S, Nikolaev VO. Regulation of the renin-angiotensin-aldosterone system by cyclic nucleotides and phosphodiesterases. Front Endocrinol (Lausanne) 2023; 14:1239492. [PMID: 37674612 PMCID: PMC10478253 DOI: 10.3389/fendo.2023.1239492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023] Open
Abstract
The renin-angiotensin-aldosterone system (RAAS) is one of the key players in the regulation of blood volume and blood pressure. Dysfunction of this system is connected with cardiovascular and renal diseases. Regulation of RAAS is under the control of multiple intracellular mechanisms. Cyclic nucleotides and phosphodiesterases are the major regulators of this system since they control expression and activity of renin and aldosterone. In this review, we summarize known mechanisms by which cyclic nucleotides and phosphodiesterases regulate renin gene expression, secretion of renin granules from juxtaglomerular cells and aldosterone production from zona glomerulosa cells of adrenal gland. We also discuss several open questions which deserve future attention.
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Affiliation(s)
- Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint Petersburg, Russia
| | - Sanika Mohagaonkar
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Viacheslav O. Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
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3
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Bastola T, Perkins GA, Kim KY, Choi S, Kwon JW, Shen Z, Strack S, Ju WK. Role of A-Kinase Anchoring Protein 1 in Retinal Ganglion Cells: Neurodegeneration and Neuroprotection. Cells 2023; 12:1539. [PMID: 37296658 PMCID: PMC10252895 DOI: 10.3390/cells12111539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/21/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
A-Kinase anchoring protein 1 (AKAP1) is a multifunctional mitochondrial scaffold protein that regulates mitochondrial dynamics, bioenergetics, and calcium homeostasis by anchoring several proteins, including protein kinase A, to the outer mitochondrial membrane. Glaucoma is a complex, multifactorial disease characterized by a slow and progressive degeneration of the optic nerve and retinal ganglion cells (RGCs), ultimately resulting in vision loss. Impairment of the mitochondrial network and function is linked to glaucomatous neurodegeneration. Loss of AKAP1 induces dynamin-related protein 1 dephosphorylation-mediated mitochondrial fragmentation and loss of RGCs. Elevated intraocular pressure triggers a significant reduction in AKAP1 protein expression in the glaucomatous retina. Amplification of AKAP1 expression protects RGCs from oxidative stress. Hence, modulation of AKAP1 could be considered a potential therapeutic target for neuroprotective intervention in glaucoma and other mitochondria-associated optic neuropathies. This review covers the current research on the role of AKAP1 in the maintenance of mitochondrial dynamics, bioenergetics, and mitophagy in RGCs and provides a scientific basis to identify and develop new therapeutic strategies that could protect RGCs and their axons in glaucoma.
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Affiliation(s)
- Tonking Bastola
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Guy A. Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Seunghwan Choi
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Jin-Woo Kwon
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Department of Ophthalmology and Visual Science, St. Vincent’s Hospital, Jungbu-daero 93, Paldal-gu, Suwon 16247, Republic of Korea
| | - Ziyao Shen
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Stefan Strack
- Department of Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA;
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
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4
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Hees JT, Harbauer AB. Metabolic Regulation of Mitochondrial Protein Biogenesis from a Neuronal Perspective. Biomolecules 2022; 12:1595. [PMID: 36358945 PMCID: PMC9687362 DOI: 10.3390/biom12111595] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 09/29/2023] Open
Abstract
Neurons critically depend on mitochondria for ATP production and Ca2+ buffering. They are highly compartmentalized cells and therefore a finely tuned mitochondrial network constantly adapting to the local requirements is necessary. For neuronal maintenance, old or damaged mitochondria need to be degraded, while the functional mitochondrial pool needs to be replenished with freshly synthesized components. Mitochondrial biogenesis is known to be primarily regulated via the PGC-1α-NRF1/2-TFAM pathway at the transcriptional level. However, while transcriptional regulation of mitochondrial genes can change the global mitochondrial content in neurons, it does not explain how a morphologically complex cell such as a neuron adapts to local differences in mitochondrial demand. In this review, we discuss regulatory mechanisms controlling mitochondrial biogenesis thereby making a case for differential regulation at the transcriptional and translational level. In neurons, additional regulation can occur due to the axonal localization of mRNAs encoding mitochondrial proteins. Hitchhiking of mRNAs on organelles including mitochondria as well as contact site formation between mitochondria and endolysosomes are required for local mitochondrial biogenesis in axons linking defects in any of these organelles to the mitochondrial dysfunction seen in various neurological disorders.
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Affiliation(s)
- Jara Tabitha Hees
- TUM Medical Graduate Center, Technical University of Munich, 81675 Munich, Germany
- Max Planck Institute for Biological Intelligence, in Foundation, 82152 Planegg-Martinsried, Germany
| | - Angelika Bettina Harbauer
- Max Planck Institute for Biological Intelligence, in Foundation, 82152 Planegg-Martinsried, Germany
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany
- Munich Cluster for Systems Neurology, 81377 Munich, Germany
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5
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Lackey L, Coria A, Ghosh AJ, Grayeski P, Hatfield A, Shankar V, Platig J, Xu Z, Ramos SBV, Silverman EK, Ortega VE, Cho MH, Hersh CP, Hobbs BD, Castaldi P, Laederach A. Alternative poly-adenylation modulates α1-antitrypsin expression in chronic obstructive pulmonary disease. PLoS Genet 2021; 17:e1009912. [PMID: 34784346 PMCID: PMC8631626 DOI: 10.1371/journal.pgen.1009912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 11/30/2021] [Accepted: 10/25/2021] [Indexed: 01/07/2023] Open
Abstract
α1-anti-trypsin (A1AT), encoded by SERPINA1, is a neutrophil elastase inhibitor that controls the inflammatory response in the lung. Severe A1AT deficiency increases risk for Chronic Obstructive Pulmonary Disease (COPD), however, the role of A1AT in COPD in non-deficient individuals is not well known. We identify a 2.1-fold increase (p = 2.5x10-6) in the use of a distal poly-adenylation site in primary lung tissue RNA-seq in 82 COPD cases when compared to 64 controls and replicate this in an independent study of 376 COPD and 267 controls. This alternative polyadenylation event involves two sites, a proximal and distal site, 61 and 1683 nucleotides downstream of the A1AT stop codon. To characterize this event, we measured the distal ratio in human primary tissue short read RNA-seq data and corroborated our results with long read RNA-seq data. Integrating these results with 3' end RNA-seq and nanoluciferase reporter assay experiments we show that use of the distal site yields mRNA transcripts with over 50-fold decreased translation efficiency and A1AT expression. We identified seven RNA binding proteins using enhanced CrossLinking and ImmunoPrecipitation precipitation (eCLIP) with one or more binding sites in the SERPINA1 3' UTR. We combined these data with measurements of the distal ratio in shRNA knockdown experiments, nuclear and cytoplasmic fractionation, and chemical RNA structure probing. We identify Quaking Homolog (QKI) as a modulator of SERPINA1 mRNA translation and confirm the role of QKI in SERPINA1 translation with luciferase reporter assays. Analysis of single-cell RNA-seq showed differences in the distribution of the SERPINA1 distal ratio among hepatocytes, macrophages, αβ-Tcells and plasma cells in the liver. Alveolar Type 1,2, dendritic cells and macrophages also vary in their distal ratio in the lung. Our work reveals a complex post-transcriptional mechanism that regulates alternative polyadenylation and A1AT expression in COPD.
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Affiliation(s)
- Lela Lackey
- Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, South Carolina, United States of America
| | - Aaztli Coria
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Auyon J. Ghosh
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Phil Grayeski
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Abigail Hatfield
- Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, South Carolina, United States of America
| | - Vijay Shankar
- Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, South Carolina, United States of America
| | - John Platig
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Zhonghui Xu
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Silvia B. V. Ramos
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Edwin K. Silverman
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Victor E. Ortega
- Department of Internal Medicine, Division of Respiratory Medicine, Center for Individualized Medicine, Mayo Clinic, Scottsdale, Arizona, United States of America
| | - Michael H. Cho
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Craig P. Hersh
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brian D. Hobbs
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Pulmonary and Critical Care Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter Castaldi
- Channing Division of Network Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Internal Medicine and Primary Care, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alain Laederach
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, United States of America
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6
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Kothandapani A, Larsen MC, Lee J, Jorgensen JS, Jefcoate CR. Distinctive functioning of STARD1 in the fetal Leydig cells compared to adult Leydig and adrenal cells. Impact of Hedgehog signaling via the primary cilium. Mol Cell Endocrinol 2021; 531:111265. [PMID: 33864885 DOI: 10.1016/j.mce.2021.111265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 03/19/2021] [Accepted: 03/25/2021] [Indexed: 10/21/2022]
Abstract
STARD1 stimulates cholesterol transfer to mitochondrial CYP11A1 for conversion to pregnenolone. A cholesterol-binding START domain is guided by an N-terminal domain in a cell selective manner. Fetal and adult Leydig cells (FLC, ALC) show distinct Stard1 regulation. sm- FISH microscopy, which resolves individual molecules of Stard1 mRNA, shows uniformly high basal expression in each FLC. In ALC, in vivo, and cultured MA-10 cells, basal Stard1 expression is minimal. PKA activates loci asynchronously, with delayed splicing/export of 3.5 kb mRNA to mitochondria. After 60 min, ALC transition to an integrated mRNA delivery to mitochondria that is seen in FLC. Sertoli cells cooperate in Stard1 stimulation in FLC by delivering DHH to the primary cilium. There PTCH, SMO and cholesterol cooperate to release GLI3 to activate the Stard1 locus, probably by directing histone changes. ALC lack cilia. PKA then primes locus activation. FLC and ALC share similar SIK/CRTC/CREB regulation characterized for adrenal cells.
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Affiliation(s)
- Anbarasi Kothandapani
- Department of Comparative Biosciences, University of Wisconsin School of Veterinary Medicine, Madison, WI, 53706, USA
| | - Michele Campaigne Larsen
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA
| | - Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA
| | - Joan S Jorgensen
- Department of Comparative Biosciences, University of Wisconsin School of Veterinary Medicine, Madison, WI, 53706, USA
| | - Colin R Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53705, USA.
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7
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Fu R, Wellman K, Baldwin A, Rege J, Walters K, Hirsekorn A, Riemondy K, Rainey WE, Mukherjee N. RNA-binding proteins regulate aldosterone homeostasis in human steroidogenic cells. RNA (NEW YORK, N.Y.) 2021; 27:rna.078727.121. [PMID: 34074709 PMCID: PMC8284322 DOI: 10.1261/rna.078727.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Angiotensin II (AngII) stimulates adrenocortical cells to produce aldosterone, a master regulator of blood pressure. Despite extensive characterization of the transcriptional and enzymatic control of adrenocortical steroidogenesis, there are still major gaps in the precise regulation of AII-induced gene expression kinetics. Specifically, we do not know the regulatory contribution of RNA-binding proteins (RBPs) and RNA decay, which can control the timing of stimulus-induced gene expression. To investigate this question, we performed a high-resolution RNA-seq time course of the AngII stimulation response and 4-thiouridine pulse labeling in a steroidogenic human cell line (H295R). We identified twelve temporally distinct gene expression responses that contained mRNA encoding proteins known to be important for various steps of aldosterone production, such as cAMP signaling components and steroidogenic enzymes. AngII response kinetics for many of these mRNAs revealed a coordinated increase in both synthesis and decay. These findings were validated in primary human adrenocortical cells stimulated ex vivo with AngII. Using a candidate screen, we identified a subset of RNA-binding protein and RNA decay factors that activate or repress AngII-stimulated aldosterone production. Among the repressors of aldosterone were BTG2, which promotes deadenylation and global RNA decay. BTG2 was induced in response to AngII stimulation and promoted the repression of mRNAs encoding pro-steroidogenic factors indicating the existence of an incoherent feedforward loop controlling aldosterone homeostasis. These data support a model in which coordinated increases in transcription and decay facilitate the major transcriptomic changes required to implement a pro-steroidogenic expression program that actively resolved to prevent aldosterone overproduction.
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Affiliation(s)
- Rui Fu
- University of Colorado Denver School of Medicine
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8
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Mancino DN, Leicaj ML, Lima A, Roig P, Guennoun R, Schumacher M, De Nicola AF, Garay LI. Developmental expression of genes involved in progesterone synthesis, metabolism and action during the post-natal cerebellar myelination. J Steroid Biochem Mol Biol 2021; 207:105820. [PMID: 33465418 DOI: 10.1016/j.jsbmb.2021.105820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/10/2020] [Accepted: 01/12/2021] [Indexed: 10/22/2022]
Abstract
Progesterone is involved in dendritogenesis, synaptogenesis and maturation of cerebellar Purkinge cells, major sites of steroid synthesis in the brain. To study a possible time-relationship between myelination, neurosteroidogenesis and steroid receptors during development of the postnatal mouse cerebellum, we determined at postnatal days 5 (P5),18 (P18) and 35 (P35) the expression of myelin basic protein (MBP), components of the steroidogenic pathway, levels of endogenous steroids and progesterone's classical and non-classical receptors. In parallel with myelin increased expression during development, P18 and P35 mice showed higher levels of cerebellar progesterone and its reduced derivatives, higher expression of steroidogenic acute regulatory protein (StAR) mRNA, cholesterol side chain cleavage enzyme (P450scc) and 5α-reductase mRNA vs. P5 mice. Other steroids such as corticosterone and its reduced derivatives and 3β-androstanodiol (ADIOL) showed a peak increase at P18 compared to P5. Progesterone membrane receptors and binding proteins (PGRMC1, mPRα, mPRβ, mPRγ, and Sigma1 receptors) mRNAs levels increased during development while that of classical progesterone receptors (PR) remained invariable. PRKO mice showed similar MBP levels than wild type. Thus, these data suggests that progesterone and its neuroactive metabolites may play a role in postnatal cerebellar myelination.
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Affiliation(s)
- Dalila Nj Mancino
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina
| | - María Luz Leicaj
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Analia Lima
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Paulina Roig
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina
| | - Rachida Guennoun
- U1195 Inserm and University Paris Saclay, University Paris Sud, 94276 Le kremlin Bicêtre, France
| | - Michael Schumacher
- U1195 Inserm and University Paris Saclay, University Paris Sud, 94276 Le kremlin Bicêtre, France
| | - Alejandro F De Nicola
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina; Department of Human Biochemistry, University of Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina
| | - Laura I Garay
- Laboratory of Neuroendocrine Biochemistry, Instituto de Biologia y Medicina Experimental-CONICET, Obligado 2490, 1428 Buenos Aires, Argentina; Department of Human Biochemistry, University of Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina.
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9
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Grozdanov PN, Masoumzadeh E, Kalscheuer VM, Bienvenu T, Billuart P, Delrue MA, Latham MP, MacDonald CC. A missense mutation in the CSTF2 gene that impairs the function of the RNA recognition motif and causes defects in 3' end processing is associated with intellectual disability in humans. Nucleic Acids Res 2020; 48:9804-9821. [PMID: 32816001 PMCID: PMC7515730 DOI: 10.1093/nar/gkaa689] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 08/03/2020] [Accepted: 08/18/2020] [Indexed: 11/25/2022] Open
Abstract
CSTF2 encodes an RNA-binding protein that is essential for mRNA cleavage and polyadenylation (C/P). No disease-associated mutations have been described for this gene. Here, we report a mutation in the RNA recognition motif (RRM) of CSTF2 that changes an aspartic acid at position 50 to alanine (p.D50A), resulting in intellectual disability in male patients. In mice, this mutation was sufficient to alter polyadenylation sites in over 1300 genes critical for brain development. Using a reporter gene assay, we demonstrated that C/P efficiency of CSTF2D50A was lower than wild type. To account for this, we determined that p.D50A changed locations of amino acid side chains altering RNA binding sites in the RRM. The changes modified the electrostatic potential of the RRM leading to a greater affinity for RNA. These results highlight the significance of 3′ end mRNA processing in expression of genes important for brain plasticity and neuronal development.
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Affiliation(s)
- Petar N Grozdanov
- Department of Cell Biology & Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6540, USA
| | - Elahe Masoumzadeh
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Vera M Kalscheuer
- Max Planck Institute for Molecular Genetics, Research Group Development and Disease, Ihnestr. 63-73, D-14195 Berlin, Germany
| | - Thierry Bienvenu
- Institut de Psychiatrie et de Neurosciences de Paris, Inserm U1266, 102 rue de la Santé, 75014 Paris, France
| | - Pierre Billuart
- Institut de Psychiatrie et de Neurosciences de Paris, Inserm U1266, 102 rue de la Santé, 75014 Paris, France
| | - Marie-Ange Delrue
- Département de Génétique Médicale, CHU Sainte Justine, Montréal, Canada
| | - Michael P Latham
- Department of Chemistry & Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Clinton C MacDonald
- Department of Cell Biology & Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6540, USA
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10
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Gabrovsek L, Collins KB, Aggarwal S, Saunders LM, Lau HT, Suh D, Sancak Y, Trapnell C, Ong SE, Smith FD, Scott JD. A-kinase-anchoring protein 1 (dAKAP1)-based signaling complexes coordinate local protein synthesis at the mitochondrial surface. J Biol Chem 2020; 295:10749-10765. [PMID: 32482893 PMCID: PMC7397098 DOI: 10.1074/jbc.ra120.013454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/20/2020] [Indexed: 12/30/2022] Open
Abstract
Compartmentalization of macromolecules is a ubiquitous molecular mechanism that drives numerous cellular functions. The appropriate organization of enzymes in space and time enables the precise transmission and integration of intracellular signals. Molecular scaffolds constrain signaling enzymes to influence the regional modulation of these physiological processes. Mitochondrial targeting of protein kinases and protein phosphatases provides a means to locally control the phosphorylation status and action of proteins on the surface of this organelle. Dual-specificity protein kinase A anchoring protein 1 (dAKAP1) is a multivalent binding protein that targets protein kinase A (PKA), RNAs, and other signaling enzymes to the outer mitochondrial membrane. Many AKAPs recruit a diverse set of binding partners that coordinate a broad range of cellular processes. Here, results of MS and biochemical analyses reveal that dAKAP1 anchors additional components, including the ribonucleoprotein granule components La-related protein 4 (LARP4) and polyadenylate-binding protein 1 (PABPC1). Local translation of mRNAs at organelles is a means to spatially control the synthesis of proteins. RNA-Seq data demonstrate that dAKAP1 binds mRNAs encoding proteins required for mitochondrial metabolism, including succinate dehydrogenase. Functional studies suggest that the loss of dAKAP1-RNA interactions reduces mitochondrial electron transport chain activity. Hence, dAKAP1 plays a previously unappreciated role as a molecular interface between second messenger signaling and local protein synthesis machinery.
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Affiliation(s)
- Laura Gabrovsek
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington, USA
| | - Kerrie B Collins
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Stacey Aggarwal
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Lauren M Saunders
- Program in Molecular and Cellular Biology, University of Washington, Seattle, Washington, USA
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Danny Suh
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Yasemin Sancak
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Cole Trapnell
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
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11
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Larsen MC, Lee J, Jorgensen JS, Jefcoate CR. STARD1 Functions in Mitochondrial Cholesterol Metabolism and Nascent HDL Formation. Gene Expression and Molecular mRNA Imaging Show Novel Splicing and a 1:1 Mitochondrial Association. Front Endocrinol (Lausanne) 2020; 11:559674. [PMID: 33193082 PMCID: PMC7607000 DOI: 10.3389/fendo.2020.559674] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
STARD1 moves cholesterol (CHOL) from the outer mitochondrial membrane (OMM) to the inner membrane (IMM) in steroidogenic cells. This activity is integrated into CHOL trafficking and synthesis homeostasis, involving uptake through SR-B1 and LDL receptors and distribution through endosomes, ER, and lipid droplets. In adrenal cells, STARD1 is imported into the mitochondrial matrix accompanied by delivery of several hundred CHOL molecules. This transfer limits CYP11A1-mediated generation of pregnenolone. CHOL transfer is coupled to translation of STARD1 mRNA at the OMM. In testis cells, slower CHOL trafficking seems to be limiting. STARD1 also functions in a slower process through ER OMM contacts. The START domain of STARD1 is utilized by a family of genes, which includes additional STARD (forms 3-6) and GRAMD1B proteins that transfer CHOL. STARD forms 2 and 7 deliver phosphatidylcholine. STARD1 and STARD7 target their respective activities to mitochondria, via N-terminal domains (NTD) of over 50 amino acids. The NTD is not essential for steroidogenesis but exerts tissue-selective enhancement (testis>>adrenal). Three conserved sites for cleavage by the mitochondrial processing protease (MPP) generate three forms, each potentially with specific functions, as demonstrated in STARD7. STARD1 is expressed in macrophage and cardiac repair fibroblasts. Additional functions include CHOL metabolism by CYP27A1 that directs activation of LXR and CHOL export processes. STARD1 generates 3.5- and 1.6-kb mRNA from alternative polyadenylation. The 3.5-kb form exclusively binds the PKA-induced regulator, TIS11b, which binds at conserved sites in the extended 3'UTR to control mRNA translation and turnover. STARD1 expression also exhibits a novel, slow splicing that delayed splicing delivery of mRNA to mitochondria. Stimulation of transcription by PKA is directed by suppression of SIK forms that activate a CRTC/CREB/CBP promoter complex. This process is critical to pulsatile hormonal activation in vivo. sm-FISH RNA imaging shows a flow of single STARD1 mRNA particles from asymmetric accumulations of primary transcripts at gene loci to 1:1 complex of 3.5-kb mRNA with peri-nuclear mitochondria. Adrenal cells are similar but distinguished from testis cells by appreciable basal expression prior to hormonal activation. This difference is conserved in culture and in vivo.
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Affiliation(s)
- Michele Campaigne Larsen
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- Endocrinology and Reproductive Physiology Program, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Joan S. Jorgensen
- Endocrinology and Reproductive Physiology Program, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- Department of Comparative Biosciences, University of Wisconsin School of Veterinary Medicine, Madison, WI, United States
| | - Colin R. Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- Endocrinology and Reproductive Physiology Program, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- *Correspondence: Colin R. Jefcoate,
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12
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Marin W. A-kinase anchoring protein 1 (AKAP1) and its role in some cardiovascular diseases. J Mol Cell Cardiol 2019; 138:99-109. [PMID: 31783032 DOI: 10.1016/j.yjmcc.2019.11.154] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/08/2019] [Accepted: 11/22/2019] [Indexed: 01/09/2023]
Abstract
A-kinase anchoring proteins (AKAPs) play crucial roles in regulating compartmentalized multi-protein signaling networks related to PKA-mediated phosphorylation. The mitochondrial AKAP - AKAP1 proteins are enriched in heart and play cardiac protective roles. This review aims to thoroughly summarize AKAP1 variants from their sequence features to the structure-function relationships between AKAP1 and its binding partners, as well as the molecular mechanisms of AKAP1 in cardiac hypertrophy, hypoxia-induced myocardial infarction and endothelial cells dysfunction, suggesting AKAP1 as a candidate for cardiovascular therapy.
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Affiliation(s)
- Wenwen Marin
- Institute for Translational Medicine, Medical Faculty of Qingdao University, Qingdao 266021, China.
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13
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Helfenberger KE, Castillo AF, Mele PG, Fiore A, Herrera L, Finocchietto P, Podestá EJ, Poderoso C. Angiotensin II stimulation promotes mitochondrial fusion as a novel mechanism involved in protein kinase compartmentalization and cholesterol transport in human adrenocortical cells. J Steroid Biochem Mol Biol 2019; 192:105413. [PMID: 31202858 DOI: 10.1016/j.jsbmb.2019.105413] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 05/10/2019] [Accepted: 06/13/2019] [Indexed: 01/22/2023]
Abstract
In steroid-producing cells, cholesterol transport from the outer to the inner mitochondrial membrane is the first and rate-limiting step for the synthesis of all steroid hormones. Cholesterol can be transported into mitochondria by specific mitochondrial protein carriers like the steroidogenic acute regulatory protein (StAR). StAR is phosphorylated by mitochondrial ERK in a cAMP-dependent transduction pathway to achieve maximal steroid production. Mitochondria are highly dynamic organelles that undergo replication, mitophagy and morphology changes, all processes allowed by mitochondrial fusion and fission, known as mitochondrial dynamics. Mitofusin (Mfn) 1 and 2 are GTPases involved in the regulation of fusion, while dynamin-related protein 1 (Drp1) is the major regulator of mitochondrial fission. Despite the role of mitochondrial dynamics in neurological and endocrine disorders, little is known about fusion/fission in steroidogenic tissues. In this context, the present work aimed to study the role of angiotensin II (Ang II) in protein subcellular compartmentalization, mitochondrial dynamics and the involvement of this process in the regulation of aldosterone synthesis. We demonstrate here that Ang II stimulation promoted the recruitment and activation of PKCε, ERK and its upstream kinase MEK to the mitochondria, all of them essential for steroid synthesis. Moreover, Ang II prompted a shift from punctate to tubular/elongated (fusion) mitochondrial shape, in line with the observation of hormone-dependent upregulation of Mfn2 levels. Concomitantly, mitochondrial Drp1 was diminished, driving mitochondria toward fusion. Moreover, Mfn2 expression is required for StAR, ERK and MEK mitochondrial localization and ultimately for aldosterone synthesis. Collectively, this study provides fresh insights into the importance of hormonal regulation in mitochondrial dynamics as a novel mechanism involved in aldosterone production.
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Affiliation(s)
- Katia E Helfenberger
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Ana F Castillo
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Pablo G Mele
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Ana Fiore
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Lucía Herrera
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Paola Finocchietto
- Universidad de Buenos Aires, Facultad de Medicina, Hospital de Clínicas "José de San Martín", Laboratorio del Metabolismo del Oxígeno, Av. Córdoba 2351, C1121ABJ, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Ciudad de Buenos Aires, Argentina
| | - Ernesto J Podestá
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina
| | - Cecilia Poderoso
- Universidad de Buenos Aires, Facultad de Medicina, Departamento de Bioquímica Humana, Paraguay 2155 5th floor, C1121ABG, Ciudad de Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Investigaciones Biomédicas (INBIOMED), Ciudad de Buenos Aires, Argentina.
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14
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Grozdanov PN, Masoumzadeh E, Latham MP, MacDonald CC. The structural basis of CstF-77 modulation of cleavage and polyadenylation through stimulation of CstF-64 activity. Nucleic Acids Res 2018; 46:12022-12039. [PMID: 30257008 PMCID: PMC6294498 DOI: 10.1093/nar/gky862] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 08/31/2018] [Accepted: 09/12/2018] [Indexed: 01/14/2023] Open
Abstract
Cleavage and polyadenylation (C/P) of mRNA is an important cellular process that promotes increased diversity of mRNA isoforms and could change their stability in different cell types. The cleavage stimulation factor (CstF) complex, part of the C/P machinery, binds to U- and GU-rich sequences located downstream from the cleavage site through its RNA-binding subunit, CstF-64. Less is known about the function of the other two subunits of CstF, CstF-77 and CstF-50. Here, we show that the carboxy-terminus of CstF-77 plays a previously unrecognized role in enhancing C/P by altering how the RNA recognition motif (RRM) of CstF-64 binds RNA. In support of this finding, we also show that CstF-64 relies on CstF-77 to be transported to the nucleus; excess CstF-64 localizes to the cytoplasm, possibly via interaction with cytoplasmic RNAs. Reverse genetics and nuclear magnetic resonance studies of recombinant CstF-64 (RRM-Hinge) and CstF-77 (monkeytail-carboxy-terminal domain) indicate that the last 30 amino acids of CstF-77 increases the stability of the RRM, thus altering the affinity of the complex for RNA. These results provide new insights into the mechanism by which CstF regulates the location of the RNA cleavage site during C/P.
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Affiliation(s)
- Petar N Grozdanov
- Department of Cell Biology & Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6540, USA
| | - Elahe Masoumzadeh
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Michael P Latham
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Clinton C MacDonald
- Department of Cell Biology & Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6540, USA
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15
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Selvaraj V, Stocco DM, Clark BJ. Current knowledge on the acute regulation of steroidogenesis. Biol Reprod 2018; 99:13-26. [PMID: 29718098 PMCID: PMC6044331 DOI: 10.1093/biolre/ioy102] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/23/2018] [Accepted: 04/26/2018] [Indexed: 12/31/2022] Open
Abstract
How rapid induction of steroid hormone biosynthesis occurs in response to trophic hormone stimulation of steroidogenic cells has been a subject of intensive investigation for approximately six decades. A key observation made very early was that acute regulation of steroid biosynthesis required swift and timely synthesis of a new protein whose role appeared to be involved in the delivery of the substrate for all steroid hormones, cholesterol, from the outer to the inner mitochondrial membrane where the process of steroidogenesis begins. It was quickly learned that this transfer of cholesterol to the inner mitochondrial membrane was the regulated and rate-limiting step in steroidogenesis. Following this observation, the quest for this putative regulator protein(s) began in earnest in the late 1950s. This review provides a history of this quest, the candidate proteins that arose over the years and facts surrounding their rise or decline. Only two have persisted-translocator protein (TSPO) and the steroidogenic acute regulatory protein (StAR). We present a detailed summary of the work that has been published for each of these two proteins, the specific data that has appeared in support of their role in cholesterol transport and steroidogenesis, and the ensuing observations that have arisen in recent years that have refuted the role of TSPO in this process. We believe that the only viable candidate that has been shown to be indispensable is the StAR protein. Lastly, we provide our view on what may be the most important questions concerning the acute regulation of steroidogenesis that need to be asked in future.
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Affiliation(s)
- Vimal Selvaraj
- Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Douglas M Stocco
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA
| | - Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky, USA
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16
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Jefcoate CR, Lee J. Cholesterol signaling in single cells: lessons from STAR and sm-FISH. J Mol Endocrinol 2018; 60:R213-R235. [PMID: 29691317 PMCID: PMC6324173 DOI: 10.1530/jme-17-0281] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 03/06/2018] [Indexed: 12/11/2022]
Abstract
Cholesterol is an important regulator of cell signaling, both through direct impacts on cell membranes and through oxy-metabolites that activate specific receptors (steroids, hydroxy-cholesterols, bile acids). Cholesterol moves slowly through and between cell membranes with the assistance of specific binding proteins and transfer processes. The prototype cholesterol regulator is the Steroidogenesis Acute Regulatory (STAR), which moves cholesterol into mitochondria, where steroid synthesis is initiated by cytochrome P450 11A1 in multiple endocrine cell types. CYP27A1 generates hydroxyl cholesterol metabolites that activate LXR nuclear receptors to control cholesterol homeostatic and transport mechanisms. LXR regulation of cholesterol transport and storage as cholesterol ester droplets is shared by both steroid-producing cells and macrophage. This cholesterol signaling is crucial to brain neuron regulation by astrocytes and microglial macrophage, mediated by ApoE and sensitive to disruption by β-amyloid plaques. sm-FISH delivers appreciable insights into signaling in single cells, by resolving single RNA molecules as mRNA and by quantifying pre-mRNA at gene loci. sm-FISH has been applied to problems in physiology, embryo development and cancer biology, where single cell features have critical impacts. sm-FISH identifies novel features of STAR transcription in adrenal and testis cells, including asymmetric expression at individual gene loci, delayed splicing and 1:1 association of mRNA with mitochondria. This may represent a functional unit for the translation-dependent cholesterol transfer directed by STAR, which integrates into mitochondrial fusion dynamics. Similar cholesterol dynamics repeat with different players in the cycling of cholesterol between astrocytes and neurons in the brain, which may be abnormal in neurodegenerative diseases.
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Affiliation(s)
- Colin R Jefcoate
- Department of Cell and Regenerative Biology and the Endocrinology and Reproductive Physiology ProgramUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Jinwoo Lee
- Department of Cell and Regenerative Biology and the Endocrinology and Reproductive Physiology ProgramUniversity of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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17
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Chen F, Luo M, Lai F, Yu C, Cheng H, Zhou R. Biased Duplications and Loss of Members in Tdrd Family in Teleost Fish. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2017; 328:727-736. [DOI: 10.1002/jez.b.22757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/29/2017] [Accepted: 06/02/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Feng Chen
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
| | - Majing Luo
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
| | - Fengling Lai
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
| | - Chunlai Yu
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
| | - Hanhua Cheng
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
| | - Rongjia Zhou
- Hubei Key Laboratory of Cell Homeostasis; Laboratory of Molecular and Developmental Genetics; College of Life Sciences; Wuhan University; Wuhan P. R. China
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18
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Lee J, Yamazaki T, Dong H, Jefcoate C. A single cell level measurement of StAR expression and activity in adrenal cells. Mol Cell Endocrinol 2017; 441:22-30. [PMID: 27521960 PMCID: PMC5896326 DOI: 10.1016/j.mce.2016.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/03/2016] [Accepted: 08/08/2016] [Indexed: 01/31/2023]
Abstract
The Steroidogenic acute regulatory protein (StAR) directs mitochondrial cholesterol uptake through a C-terminal cholesterol binding domain (CBD) and a 62 amino acid N-terminal regulatory domain (NTD) that contains an import sequence and conserved sites for inner membrane metalloproteases. Deletion of the NTD prevents mitochondrial import while maintaining steroidogenesis but with compromised cholesterol homeostasis. The rapid StAR-mediated cholesterol transfer in adrenal cells depends on concerted mRNA translation, p37 StAR phosphorylation and controlled NTD cleavage. The NTD controls this process with two cAMP-inducible modulators of, respectively, transcription and translation SIK1 and TIS11b/Znf36l1. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA resolves slow RNA splicing at the gene loci in cAMP-induced Y-1 cells and transfer of individual 3.5 kB mRNA molecules to mitochondria. StAR transcription depends on the CREB coactivator CRTC2 and PKA inhibition of the highly inducible suppressor kinase SIK1 and a basal counterpart SIK2. PKA-inducible TIS11b/Znf36l1 binds specifically to highly conserved elements in exon 7 thereby suppressing formation of mRNA and subsequent translation. Co-expression of SIK1, Znf36l1 with 3.5 kB StAR mRNA may limit responses to pulsatile signaling by ACTH while regulating the transition to more prolonged stress.
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Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Hui Dong
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United States
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States; Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States.
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19
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Abstract
Adrenocorticotropin hormone (ACTH) produced by the anterior pituitary stimulates glucocorticoid synthesis by the adrenal cortex. The first step in glucocorticoid synthesis is the delivery of cholesterol to the mitochondrial matrix where the first enzymatic reaction in the steroid hormone biosynthetic pathway occurs. A key response of adrenal cells to ACTH is activation of the cAMP-protein kinase A (PKA) signaling pathway. PKA activation results in an acute increase in expression and function of the Steroidogenic Acute Regulatory protein (StAR). StAR plays an essential role in steroidogenesis- it controls the hormone-dependent movement of cholesterol across the mitochondrial membranes. Currently StAR's mechanism of action remains a major unanswered question in the field. However, some insight may be gained from understanding the mechanism(s) controlling the PKA-dependent phosphorylation of StAR at S194/195 (mouse/human StAR), a modification that is required for function. This mini-review provides a background on StAR's biology with a focus on StAR phosphorylation. The model for StAR translation and phosphorylation at the outer mitochondrial membrane, the location for StAR function, is presented to highlight a unifying theme emerging from diverse studies.
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Affiliation(s)
- Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville Louisville, KY, USA
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20
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Lee J, Tong T, Duan H, Foong YH, Musaitif I, Yamazaki T, Jefcoate C. Regulation of StAR by the N-terminal Domain and Coinduction of SIK1 and TIS11b/Znf36l1 in Single Cells. Front Endocrinol (Lausanne) 2016; 7:107. [PMID: 27531991 PMCID: PMC4969582 DOI: 10.3389/fendo.2016.00107] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/19/2016] [Indexed: 02/01/2023] Open
Abstract
The cholesterol transfer function of steroidogenic acute regulatory protein (StAR) is uniquely integrated into adrenal cells, with mRNA translation and protein kinase A (PKA) phosphorylation occurring at the mitochondrial outer membrane (OMM). The StAR C-terminal cholesterol-binding domain (CBD) initiates mitochondrial intermembrane contacts to rapidly direct cholesterol to Cyp11a1 in the inner membrane (IMM). The conserved StAR N-terminal regulatory domain (NTD) includes a leader sequence targeting the CBD to OMM complexes that initiate cholesterol transfer. Here, we show how the NTD functions to enhance CBD activity delivers more efficiently from StAR mRNA in adrenal cells, and then how two factors hormonally restrain this process. NTD processing at two conserved sequence sites is selectively affected by StAR PKA phosphorylation. The CBD functions as a receptor to stimulate the OMM/IMM contacts that mediate transfer. The NTD controls the transit time that integrates extramitochondrial StAR effects on cholesterol homeostasis with other mitochondrial functions, including ATP generation, inter-organelle fusion, and the major permeability transition pore in partnership with other OMM proteins. PKA also rapidly induces two additional StAR modulators: salt-inducible kinase 1 (SIK1) and Znf36l1/Tis11b. Induced SIK1 attenuates the activity of CRTC2, a key mediator of StAR transcription and splicing, but only as cAMP levels decline. TIS11b inhibits translation and directs the endonuclease-mediated removal of the 3.5-kb StAR mRNA. Removal of either of these functions individually enhances cAMP-mediated induction of StAR. High-resolution fluorescence in situ hybridization (HR-FISH) of StAR RNA reveals asymmetric transcription at the gene locus and slow RNA splicing that delays mRNA formation, potentially to synchronize with cholesterol import. Adrenal cells may retain slow transcription to integrate with intermembrane NTD activation. HR-FISH resolves individual 3.5-kb StAR mRNA molecules via dual hybridization at the 3'- and 5'-ends and reveals an unexpectedly high frequency of 1:1 pairing with mitochondria marked by the matrix StAR protein. This pairing may be central to translation-coupled cholesterol transfer. Altogether, our results show that adrenal cells exhibit high-efficiency StAR activity that needs to integrate rapid cholesterol transfer with homeostasis and pulsatile hormonal stimulation. StAR NBD, the extended 3.5-kb mRNA, SIK1, and Tis11b play important roles.
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Affiliation(s)
- Jinwoo Lee
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
| | - Tiegang Tong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Haichuan Duan
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
| | - Yee Hoon Foong
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Ibrahim Musaitif
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
| | - Takeshi Yamazaki
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
| | - Colin Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI, USA
- Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI, USA
- Molecular and Cellular Pharmacology, University of Wisconsin, Madison, WI, USA
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, USA
- *Correspondence: Colin Jefcoate,
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21
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Castillo AF, Orlando U, Helfenberger KE, Poderoso C, Podesta EJ. The role of mitochondrial fusion and StAR phosphorylation in the regulation of StAR activity and steroidogenesis. Mol Cell Endocrinol 2015; 408:73-9. [PMID: 25540920 DOI: 10.1016/j.mce.2014.12.011] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 12/16/2022]
Abstract
The steroidogenic acute regulatory (StAR) protein regulates the rate-limiting step in steroidogenesis, i.e. the delivery of cholesterol from the outer (OMM) to the inner (IMM) mitochondrial membrane. StAR is a 37-kDa protein with an N-terminal mitochondrial targeting sequence that is cleaved off during mitochondrial import to yield 30-kDa intramitochondrial StAR. StAR acts exclusively on the OMM and its activity is proportional to how long it remains on the OMM. However, the precise fashion and the molecular mechanism in which StAR remains on the OMM have not been elucidated yet. In this work we will discuss the role of mitochondrial fusion and StAR phosphorylation by the extracellular signal-regulated kinases 1/2 (ERK1/2) as part of the mechanism that regulates StAR retention on the OMM and activity.
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Affiliation(s)
- Ana F Castillo
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ulises Orlando
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Katia E Helfenberger
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Cecilia Poderoso
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina
| | - Ernesto J Podesta
- Biomedical Research Institute, INBIOMED, Department of Biochemistry, School of Medicine University of Buenos Aires, Ciudad Autónoma de Buenos Aires (CABA), C1121ABG, Argentina.
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StAR Protein Stability in Y1 and Kin-8 Mouse Adrenocortical Cells. BIOLOGY 2015; 4:200-15. [PMID: 25749137 PMCID: PMC4381226 DOI: 10.3390/biology4010200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/13/2015] [Accepted: 02/20/2015] [Indexed: 01/30/2023]
Abstract
The steroidogenic acute regulatory protein (STAR) protein expression is required for cholesterol transport into mitochondria to initiate steroidogenesis in the adrenal and gonads. STAR is synthesized as a 37 kDa precursor protein which is targeted to the mitochondria and imported and processed to an intra-mitochondrial 30 kDa protein. Tropic hormone stimulation of the cAMP-dependent protein kinase A (PKA) signaling pathway is the major contributor to the transcriptional and post-transcriptional regulation of STAR synthesis. Many studies have focused on the mechanisms of cAMP-PKA mediated control of STAR synthesis while there are few reports on STAR degradation pathways. The objective of this study was to determine the effect of cAMP-PKA-dependent signaling on STAR protein stability. We have used the cAMP-PKA responsive Y1 mouse adrenocortical cells and the PKA-deficient Kin-8 cells to measure STAR phosphorylation and protein half-life. Western blot analysis and standard radiolabeled pulse-chase experiments were used to determine STAR phosphorylation status and protein half-life, respectively. Our data demonstrate that PKA-dependent STAR phosphorylation does not contribute to 30 kDa STAR protein stability in the mitochondria. We further show that inhibition of the 26S proteasome does not block precursor STAR phosphorylation or steroid production in Y1 cells. These data suggest STAR can maintain function and promote steroidogenesis under conditions of proteasome inhibition.
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Duarte A, Castillo AF, Podestá EJ, Poderoso C. Mitochondrial fusion and ERK activity regulate steroidogenic acute regulatory protein localization in mitochondria. PLoS One 2014; 9:e100387. [PMID: 24945345 PMCID: PMC4063759 DOI: 10.1371/journal.pone.0100387] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/27/2014] [Indexed: 11/21/2022] Open
Abstract
The rate-limiting step in the biosynthesis of steroid hormones, known as the transfer of cholesterol from the outer to the inner mitochondrial membrane, is facilitated by StAR, the Steroidogenic Acute Regulatory protein. We have described that mitochondrial ERK1/2 phosphorylates StAR and that mitochondrial fusion, through the up-regulation of a fusion protein Mitofusin 2, is essential during steroidogenesis. Here, we demonstrate that mitochondrial StAR together with mitochondrial active ERK and PKA are necessary for maximal steroid production. Phosphorylation of StAR by ERK is required for the maintenance of this protein in mitochondria, observed by means of over-expression of a StAR variant lacking the ERK phosphorylation residue. Mitochondrial fusion regulates StAR levels in mitochondria after hormone stimulation. In this study, Mitofusin 2 knockdown and mitochondrial fusion inhibition in MA-10 Leydig cells diminished StAR mRNA levels and concomitantly mitochondrial StAR protein. Together our results unveil the requirement of mitochondrial fusion in the regulation of the localization and mRNA abundance of StAR. We here establish the relevance of mitochondrial phosphorylation events in the correct localization of this key protein to exert its action in specialized cells. These discoveries highlight the importance of mitochondrial fusion and ERK phosphorylation in cholesterol transport by means of directing StAR to the outer mitochondrial membrane to achieve a large number of steroid molecules per unit of StAR.
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Affiliation(s)
- Alejandra Duarte
- Institute of Biomedical Investigations (INBIOMED, UBA-CONICET), Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Ana Fernanda Castillo
- Institute of Biomedical Investigations (INBIOMED, UBA-CONICET), Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Ernesto J. Podestá
- Institute of Biomedical Investigations (INBIOMED, UBA-CONICET), Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
| | - Cecilia Poderoso
- Institute of Biomedical Investigations (INBIOMED, UBA-CONICET), Department of Biochemistry, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina
- * E-mail:
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Dyson MT, Roqueiro D, Monsivais D, Ercan CM, Pavone ME, Brooks DC, Kakinuma T, Ono M, Jafari N, Dai Y, Bulun SE. Genome-wide DNA methylation analysis predicts an epigenetic switch for GATA factor expression in endometriosis. PLoS Genet 2014; 10:e1004158. [PMID: 24603652 PMCID: PMC3945170 DOI: 10.1371/journal.pgen.1004158] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 12/18/2013] [Indexed: 11/19/2022] Open
Abstract
Endometriosis is a gynecological disease defined by the extrauterine growth of endometrial-like cells that cause chronic pain and infertility. The disease is limited to primates that exhibit spontaneous decidualization, and diseased cells are characterized by significant defects in the steroid-dependent genetic pathways that typify this process. Altered DNA methylation may underlie these defects, but few regions with differential methylation have been implicated in the disease. We mapped genome-wide differences in DNA methylation between healthy human endometrial and endometriotic stromal cells and correlated this with gene expression using an interaction analysis strategy. We identified 42,248 differentially methylated CpGs in endometriosis compared to healthy cells. These extensive differences were not unidirectional, but were focused intragenically and at sites distal to classic CpG islands where methylation status was typically negatively correlated with gene expression. Significant differences in methylation were mapped to 403 genes, which included a disproportionally large number of transcription factors. Furthermore, many of these genes are implicated in the pathology of endometriosis and decidualization. Our results tremendously improve the scope and resolution of differential methylation affecting the HOX gene clusters, nuclear receptor genes, and intriguingly the GATA family of transcription factors. Functional analysis of the GATA family revealed that GATA2 regulates key genes necessary for the hormone-driven differentiation of healthy stromal cells, but is hypermethylated and repressed in endometriotic cells. GATA6, which is hypomethylated and abundant in endometriotic cells, potently blocked hormone sensitivity, repressed GATA2, and induced markers of endometriosis when expressed in healthy endometrial cells. The unique epigenetic fingerprint in endometriosis suggests DNA methylation is an integral component of the disease, and identifies a novel role for the GATA family as key regulators of uterine physiology-aberrant DNA methylation in endometriotic cells correlates with a shift in GATA isoform expression that facilitates progesterone resistance and disease progression.
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Affiliation(s)
- Matthew T. Dyson
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Damian Roqueiro
- Laboratory of Computational Functional Genomics, Dept. Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Diana Monsivais
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - C. Mutlu Ercan
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Mary Ellen Pavone
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - David C. Brooks
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Toshiyuki Kakinuma
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Masanori Ono
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Nadereh Jafari
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Yang Dai
- Laboratory of Computational Functional Genomics, Dept. Bioengineering, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Serdar E. Bulun
- Division of Reproductive Biology Research, Dept. Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
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25
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Merrill RA, Strack S. Mitochondria: a kinase anchoring protein 1, a signaling platform for mitochondrial form and function. Int J Biochem Cell Biol 2014; 48:92-6. [PMID: 24412345 DOI: 10.1016/j.biocel.2013.12.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 11/28/2013] [Accepted: 12/26/2013] [Indexed: 12/31/2022]
Abstract
Mitochondria are best known for their role as cellular power plants, but they also serve as signaling hubs, regulating cellular proliferation, differentiation, and survival. A kinase anchoring protein 1 (AKAP1) is a scaffold protein that recruits protein kinase A (PKA) and other signaling proteins, as well as RNA, to the outer mitochondrial membrane. AKAP1 thereby integrates several second messenger cascades to modulate mitochondrial function and associated physiological and pathophysiological outcomes. Here, we review what is currently known about AKAP1's macromolecular interactions in health and disease states, including obesity. We also discuss dynamin-related protein 1 (Drp1), the enzyme that catalyzes mitochondrial fission, as one of the key substrates of the PKA/AKAP1 signaling complex in neurons. Recent evidence suggests that AKAP1 has critical roles in neuronal development and survival, which are mediated by inhibitory phosphorylation of Drp1 and maintenance of mitochondrial integrity.
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Affiliation(s)
| | - Stefan Strack
- Department of Pharmacology, University of Iowa, Iowa City, USA.
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