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Ding Y, Vanselow DJ, Yakovlev MA, Katz SR, Lin AY, Clark DP, Vargas P, Xin X, Copper JE, Canfield VA, Ang KC, Wang Y, Xiao X, De Carlo F, van Rossum DB, La Riviere P, Cheng KC. Computational 3D histological phenotyping of whole zebrafish by X-ray histotomography. eLife 2019; 8:44898. [PMID: 31063133 PMCID: PMC6559789 DOI: 10.7554/elife.44898] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 05/04/2019] [Indexed: 12/15/2022] Open
Abstract
Organismal phenotypes frequently involve multiple organ systems. Histology is a powerful way to detect cellular and tissue phenotypes, but is largely descriptive and subjective. To determine how synchrotron-based X-ray micro-tomography (micro-CT) can yield 3-dimensional whole-organism images suitable for quantitative histological phenotyping, we scanned whole zebrafish, a small vertebrate model with diverse tissues, at ~1 micron voxel resolutions. Micro-CT optimized for cellular characterization (histotomography) allows brain nuclei to be computationally segmented and assigned to brain regions, and cell shapes and volumes to be computed for motor neurons and red blood cells. Striking individual phenotypic variation was apparent from color maps of computed densities of brain nuclei. Unlike histology, the histotomography also allows the study of 3-dimensional structures of millimeter scale that cross multiple tissue planes. We expect the computational and visual insights into 3D cell and tissue architecture provided by histotomography to be useful for reference atlases, hypothesis generation, comprehensive organismal screens, and diagnostics. Diagnosing diseases, such as cancer, requires scientists and doctors to understand how cells respond to different medical conditions. A common way of studying these microscopic cell changes is by an approach called histology: thin slices of centimeter-sized samples of tissues are taken from patients, stained to distinguish cellular components, and examined for abnormal features. This powerful technique has revolutionized biology and medicine. But despite its frequent use, histology comes with limitations. To allow individual cells to be distinguished, tissues are cut into slices less than 1/20th of a millimeter thick. Histology’s dependence upon such thin slices makes it impossible to see the entirety of cells and structures that are thicker than the slice, or to accurately measure three-dimensional features such as shape or volume. Larger internal structures within the human body are routinely visualized using a technique known as computerized tomography, CT for short – whereby dozens of x-ray images are compiled together to generate a three-dimensional image. This technique has also been applied to image smaller structures. However, the resolution (the ability to distinguish between objects) and tissue contrast of these images has been insufficient for histology-based diagnosis across all cell types. Now, Ding et al. have developed a new method, by optimizing multiple components of CT scanning, that begins to provide the higher resolution and contrast needed to make diagnoses that require histological detail. To test their modified CT system, Ding et al. created three-dimensional images of whole zebrafish, measuring three millimeters to about a centimeter in length. Adjusting imaging parameters and views of these images made it possible to study features of larger-scale structures, such as the gills and the gut, that are normally inaccessible to histology. As a result of this unprecedented combination of high resolution and scale, computer analysis of these images allowed Ding et al. to measure cellular features such as size and shape, and to determine which cells belong to different brain regions, all from single reconstructions. Surprisingly, visualization of how tightly the brain cells are packed revealed striking differences between the brains of sibling zebrafish that were born the same day. This new method could be used to study changes across hundreds of cell types in any millimeter to centimetre-sized organism or tissue sample. In the future, the accurate measurements of microscopic features made possible by this new tool may help us to make drugs safer, improve tissue diagnostics, and care for our environment.
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Affiliation(s)
- Yifu Ding
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States.,Medical Scientist Training Program, Penn State College of Medicine, Hershey, United States
| | - Daniel J Vanselow
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Maksim A Yakovlev
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Spencer R Katz
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States.,Medical Scientist Training Program, Penn State College of Medicine, Hershey, United States
| | - Alex Y Lin
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Darin P Clark
- Center for In Vivo Microscopy, Duke University, Durham, United States
| | - Phillip Vargas
- Department of Radiology, The University of Chicago, Chicago, United States
| | - Xuying Xin
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Jean E Copper
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Victor A Canfield
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Khai C Ang
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Yuxin Wang
- Imaging Group, Omnivision Technologies, Inc., Santa Clara, United States
| | - Xianghui Xiao
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, United States
| | - Francesco De Carlo
- Advanced Photon Source, Argonne National Laboratory, Lemont, United States
| | - Damian B van Rossum
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
| | - Patrick La Riviere
- Department of Radiology, The University of Chicago, Chicago, United States
| | - Keith C Cheng
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, United States.,Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine, Hershey, United States
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Donaldson K, Buchanich JM, Grigson PS, Deneke E, Donaldson K, Vrana KE, Sacks DB, Kuehn GJ, Cardamone D, Pesce A, Smiley S, Nickley J, Krock K, Thomas R, Wilkerson ML, Farag HA, Challa SR, Tice AM, Wolk DM, Prichard J, Grant ML, Regmi S, Kerbacher B, Quinton LE, Farag HA, Tice AM, Wolk DM, Olson J, Haynes A, Yu E, McCully KS, Assi J, Wong M, Zarrin-Khameh N, Nifong TP, Hawker CD, Carlton GT, Rivera JM, Foulis PR, Zuraw A, Morlote D, Peker D, Reddy V, Harada S, Crutchfield C, Zander D, Barbhuiya MA, Pederson EC, Straub ML, Scott SC, Neibauer TL, Salter WF, Creer MH, Zhu Y, Bornhorst JA, Theobald JP, Algeciras-Schimnich A, Cao L, Knox J, Hardy R, Texas HJ, McGuire MF, Hunter RL, Brown RE, Hicks J, Hicks J, Cai Z, Brown RE, Ali Y, Cheng KC, Katz SR, Ding Y, Vanselow DJ, Yakovlev MA, Lin AY, Clark DP, Vargas P, Xin X, Copper JE, Canfield VA, Ang KC, Wang Y, Xiao X, De Carlo F, van Rossum DB, La Rivière PJ, Newell J, Hossler C, Roche M, Warrick J, Phaeton R, Kesterson J, Donaldson K, Myers C, Barrios R, Mintz P, Robyak K, Hamilton C, McGhee P, Pederson C, Straub M, Scott S, Neibauer T, Salter W, Creer M, Zhu Y, Hamilton C, Robyak K, McGhee P, Pederson C, Straub M, Scott S, Neibauer T, Salter W, Creer M, Zhu Y, Singh N, Morlote D, Vnencak-Jones C, Yemelyanova A, Harada S, Shah M, Moghadamtousi SZ, Lan C, Duose D, Hu P, Esquenazi Y, Luthra R, Ballester LY, Koenig AN, Liu CG, Zhang J, Kalia A, Al-Habib A, Van Arsdall M, Dhingra S, Patel K, Tatevian N. Abstracts of Presentations at the Association of Clinical Scientists 139 th Meeting Hershey, PA, May 15-18, 2019. Ann Clin Lab Sci 2019; 49:403-416. [PMID: 31308044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Robert E Brown
- UT Health McGovern Medical School at Houston, Houston, TX
| | | | | | | | | | | | - Keith C Cheng
- Department of Pathology, Penn State College of Medicine
| | | | - Yifu Ding
- Department of Pathology, Penn State College of Medicine
| | | | | | - Alex Y Lin
- Department of Pathology, Penn State College of Medicine
| | | | | | - Xuying Xin
- Department of Pathology, Penn State College of Medicine
| | - Jean E Copper
- Department of Pathology, Penn State College of Medicine
| | | | - Khai C Ang
- Department of Pathology, Penn State College of Medicine
| | - Yuxin Wang
- Omnivision Technologies, Santa Clara, CA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory, University of Chicago
- Brookhaven National Laboratory, University of Chicago
| | - Francesco De Carlo
- Advanced Photon Source, Argonne National Laboratory, University of Chicago
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Mauli Shah
- Graduate Program in Diagnostic Genetics, School of Health Professions, UT MD Anderson Cancer Center, Houston, TX
| | | | - Chieh Lan
- Department of Translational Molecular Pathology, Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Dzifa Duose
- Department of Translational Molecular Pathology, Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Peter Hu
- Graduate Program in Diagnostic Genetics, School of Health Professions, UT MD Anderson Cancer Center, Houston, TX
| | - Yoshua Esquenazi
- Department of Neurosurgery, McGovern Medical School, University of Texas Health Science Center, Houston, TX
| | - Rajyalakshmi Luthra
- Department of Hematopathology, Division of Pathology and Laboratory Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Leomar Y Ballester
- Department of Neurosurgery, McGovern Medical School, University of Texas Health Science Center, Houston, TX
| | | | | | | | | | - Ali Al-Habib
- The University of Texas Health Science Center, Houston, TX
| | | | | | | | - Nina Tatevian
- The University of Texas Health Science Center, Houston, TX
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Lin AY, Ding Y, Vanselow DJ, Katz SR, Yakovlev MA, Clark DP, Mandrell D, Copper JE, van Rossum DB, Cheng KC. Rigid Embedding of Fixed and Stained, Whole, Millimeter-Scale Specimens for Section-free 3D Histology by Micro-Computed Tomography. J Vis Exp 2018. [PMID: 30394379 PMCID: PMC6235553 DOI: 10.3791/58293] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
For over a hundred years, the histological study of tissues has been the gold standard for medical diagnosis because histology allows all cell types in every tissue to be identified and characterized. Our laboratory is actively working to make technological advances in X-ray micro-computed tomography (micro-CT) that will bring the diagnostic power of histology to the study of full tissue volumes at cellular resolution (i.e., an X-ray Histo-tomography modality). Toward this end, we have made targeted improvements to the sample preparation pipeline. One key optimization, and the focus of the present work, is a straightforward method for rigid embedding of fixed and stained millimeter-scale samples. Many of the published methods for sample immobilization and correlative micro-CT imaging rely on placing the samples in paraffin wax, agarose, or liquids such as alcohol. Our approach extends this work with custom procedures and the design of a 3-dimensional printable apparatus to embed the samples in an acrylic resin directly into polyimide tubing, which is relatively transparent to X-rays. Herein, sample preparation procedures are described for the samples from 0.5 to 10 mm in diameter, which would be suitable for whole zebrafish larvae and juveniles, or other animals and tissue samples of similar dimensions. As proof of concept, we have embedded the specimens from Danio, Drosophila, Daphnia, and a mouse embryo; representative images from 3-dimensional scans for three of these samples are shown. Importantly, our methodology leads to multiple benefits including rigid immobilization, long-term preservation of laboriously-created resources, and the ability to re-interrogate samples.
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Affiliation(s)
- Alex Y Lin
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine
| | - Yifu Ding
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine; Medical Scientist Training Program, Penn State College of Medicine
| | - Daniel J Vanselow
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine
| | - Spencer R Katz
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine; Medical Scientist Training Program, Penn State College of Medicine
| | - Maksim A Yakovlev
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine
| | - Darin P Clark
- Center for In Vivo Microscopy, Duke University Medical Center
| | | | - Jean E Copper
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine
| | - Damian B van Rossum
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine
| | - Keith C Cheng
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine; Division of Experimental Pathology, Department of Pathology, Penn State College of Medicine;
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Pisupati A, Mickolajczyk KJ, Horton W, van Rossum DB, Anishkin A, Chintapalli SV, Li X, Chu-Luo J, Busey G, Hancock WO, Jegla T. The S6 gate in regulatory Kv6 subunits restricts heteromeric K + channel stoichiometry. J Gen Physiol 2018; 150:1702-1721. [PMID: 30322883 PMCID: PMC6279357 DOI: 10.1085/jgp.201812121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/03/2018] [Accepted: 09/26/2018] [Indexed: 11/24/2022] Open
Abstract
Atypical substitutions in the S6 activation gate sequence distinguish “regulatory” Kv subunits, which cannot homotetramerize due to T1 self-incompatibility. Pisupati et al. show that such substitutions in Kv6 work together with self-incompatibility to restrict Kv2:Kv6 heteromeric stoichiometry to 3:1. The Shaker-like family of voltage-gated K+ channels comprises four functionally independent gene subfamilies, Shaker (Kv1), Shab (Kv2), Shaw (Kv3), and Shal (Kv4), each of which regulates distinct aspects of neuronal excitability. Subfamily-specific assembly of tetrameric channels is mediated by the N-terminal T1 domain and segregates Kv1–4, allowing multiple channel types to function independently in the same cell. Typical Shaker-like Kv subunits can form functional channels as homotetramers, but a group of mammalian Kv2-related genes (Kv5.1, Kv6s, Kv8s, and Kv9s) encodes subunits that have a “silent” or “regulatory” phenotype characterized by T1 self-incompatibility. These channels are unable to form homotetramers, but instead heteromerize with Kv2.1 or Kv2.2 to diversify the functional properties of these delayed rectifiers. While T1 self-incompatibility predicts that these heterotetramers could contain up to two regulatory (R) subunits, experiments show a predominance of 3:1R stoichiometry in which heteromeric channels contain a single regulatory subunit. Substitution of the self-compatible Kv2.1 T1 domain into the regulatory subunit Kv6.4 does not alter the stoichiometry of Kv2.1:Kv6.4 heteromers. Here, to identify other channel structures that might be responsible for favoring the 3:1R stoichiometry, we compare the sequences of mammalian regulatory subunits to independently evolved regulatory subunits from cnidarians. The most widespread feature of regulatory subunits is the presence of atypical substitutions in the highly conserved consensus sequence of the intracellular S6 activation gate of the pore. We show that two amino acid substitutions in the S6 gate of the regulatory subunit Kv6.4 restrict the functional stoichiometry of Kv2.1:Kv6.4 to 3:1R by limiting the formation and function of 2:2R heteromers. We propose a two-step model for the evolution of the asymmetric 3:1R stoichiometry, which begins with evolution of self-incompatibility to establish the regulatory phenotype, followed by drift of the activation gate consensus sequence under relaxed selection to limit stoichiometry to 3:1R.
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Affiliation(s)
- Aditya Pisupati
- Department of Biology, Pennsylvania State University, University Park, PA.,Medical Scientist Training Program, College of Medicine, Pennsylvania State University, Hershey, PA
| | - Keith J Mickolajczyk
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA
| | - William Horton
- Department of Animal Science, Pennsylvania State University, University Park, PA
| | - Damian B van Rossum
- The Jake Gittlen Laboratories for Cancer Research, College of Medicine, Pennsylvania State University, Hershey, PA.,Division of Experimental Pathology, Department of Pathology, College of Medicine, Pennsylvania State University, Hershey, PA
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD
| | - Sree V Chintapalli
- Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Xiaofan Li
- Department of Biology, Pennsylvania State University, University Park, PA
| | - Jose Chu-Luo
- Department of Biology, Pennsylvania State University, University Park, PA
| | - Gregory Busey
- Department of Biology, Pennsylvania State University, University Park, PA
| | - William O Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA
| | - Timothy Jegla
- Department of Biology, Pennsylvania State University, University Park, PA .,Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA
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5
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Copper JE, Budgeon LR, Foutz CA, van Rossum DB, Vanselow DJ, Hubley MJ, Clark DP, Mandrell DT, Cheng KC. Comparative analysis of fixation and embedding techniques for optimized histological preparation of zebrafish. Comp Biochem Physiol C Toxicol Pharmacol 2018; 208:38-46. [PMID: 29157956 PMCID: PMC5936644 DOI: 10.1016/j.cbpc.2017.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 10/18/2022]
Abstract
In recognition of the importance of zebrafish as a model organism for studying human disease, we have created zebrafish content for a web-based reference atlas of microanatomy for comparing histology and histopathology between model systems and with humans (http://bio-atlas.psu.edu). Fixation, decalcification, embedding, and sectioning of zebrafish were optimized to maximize section quality. A comparison of protocols involving six fixatives showed that 10% Neutral Buffered Formalin at 21°C for 24h yielded excellent results. Sectioning of juveniles and adults requires bone decalcification; EDTA at 0.35M produced effective decalcification in 21-day-old juveniles through adults (≥~3Months). To improve section plane consistency in sets of larvae, we have developed new array casting molds based on the outside contours of larvae derived from 3D microCT images. Tissue discontinuity in sections, a common barrier to creating quality sections of zebrafish, was minimized by processing and embedding the formalin-fixed zebrafish tissues in plasticized forms of paraffin wax, and by periodic hydration of the block surface in ice water between sets of sections. Optimal H&E (Hematoxylin and Eosin) staining was achieved through refinement of standard protocols. High quality slide scans produced from glass histology slides were digitally processed to maximize image quality, and experimental replicates posted as full slides as part of this publication. Modifications to tissue processing are still needed to eliminate the need for block surface hydration. The further addition of slide collections from other model systems and 3D tools for visualizing tissue architecture would greatly increase the utility of the digital atlas.
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Affiliation(s)
- Jean E Copper
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Lynn R Budgeon
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Christina A Foutz
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Damian B van Rossum
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Daniel J Vanselow
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Margaret J Hubley
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Darin P Clark
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | | | - Keith C Cheng
- Jake Gittlen Cancer Research Laboratories, Department of Pathology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA.
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Caraveo G, Soste M, Cappelleti V, Fanning S, van Rossum DB, Whitesell L, Huang Y, Chung CY, Baru V, Zaichick S, Picotti P, Lindquist S. FKBP12 contributes to α-synuclein toxicity by regulating the calcineurin-dependent phosphoproteome. Proc Natl Acad Sci U S A 2017; 114:E11313-E11322. [PMID: 29229832 PMCID: PMC5748183 DOI: 10.1073/pnas.1711926115] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcineurin is an essential Ca2+-dependent phosphatase. Increased calcineurin activity is associated with α-synuclein (α-syn) toxicity, a protein implicated in Parkinson's Disease (PD) and other neurodegenerative diseases. Calcineurin can be inhibited with Tacrolimus through the recruitment and inhibition of the 12-kDa cis-trans proline isomerase FK506-binding protein (FKBP12). Whether calcineurin/FKBP12 represents a native physiologically relevant assembly that occurs in the absence of pharmacological perturbation has remained elusive. We leveraged α-syn as a model to interrogate whether FKBP12 plays a role in regulating calcineurin activity in the absence of Tacrolimus. We show that FKBP12 profoundly affects the calcineurin-dependent phosphoproteome, promoting the dephosphorylation of a subset of proteins that contributes to α-syn toxicity. Using a rat model of PD, partial elimination of the functional interaction between FKBP12 and calcineurin, with low doses of the Food and Drug Administration (FDA)-approved compound Tacrolimus, blocks calcineurin's activity toward those proteins and protects against the toxic hallmarks of α-syn pathology. Thus, FKBP12 can endogenously regulate calcineurin activity with therapeutic implications for the treatment of PD.
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Affiliation(s)
- Gabriela Caraveo
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142;
| | - Martin Soste
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule Zurich, 8092 Zurich, Switzerland
| | - Valentina Cappelleti
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule Zurich, 8092 Zurich, Switzerland
- Department of Computational Biology, Research and Innovation Centre, Foundation Edmund Mach, 38010 San Michele, Italy
| | - Saranna Fanning
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Damian B van Rossum
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033
- The Jake Gittlen Laboratories for Cancer Research, Penn State College of Medicine, Hershey, PA 17033
| | - Luke Whitesell
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Yanmei Huang
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Chee Yeun Chung
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Valeriya Baru
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
| | - Sofia Zaichick
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Paola Picotti
- Department of Biology, Institute of Biochemistry, Eidgenössische Technische Hochschule Zurich, 8092 Zurich, Switzerland
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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7
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Jegla T, Nguyen MM, Feng C, Goetschius DJ, Luna E, van Rossum DB, Kamel B, Pisupati A, Milner ES, Rolls MM. An Ancient Role for Giant Ankyrins in Axon Initial Segment Organization. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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8
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Xin X, Clark D, Ang KC, van Rossum DB, Copper J, Xiao X, La Riviere PJ, Cheng KC. Synchrotron microCT imaging of soft tissue in juvenile zebrafish reveals retinotectal projections. Proc SPIE Int Soc Opt Eng 2017; 10060. [PMID: 32733117 DOI: 10.1117/12.2267477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Biomedical research and clinical diagnosis would benefit greatly from full volume determinations of anatomical phenotype. Comprehensive tools for morphological phenotyping are central for the emerging field of phenomics, which requires high-throughput, systematic, accurate, and reproducible data collection from organisms affected by genetic, disease, or environmental variables. Theoretically, complete anatomical phenotyping requires the assessment of every cell type in the whole organism, but this ideal is presently untenable due to the lack of an unbiased 3D imaging method that allows histopathological assessment of any cell type despite optical opacity. Histopathology, the current clinical standard for diagnostic phenotyping, involves the microscopic study of tissue sections to assess qualitative aspects of tissue architecture, disease mechanisms, and physiological state. However, quantitative features of tissue architecture such as cellular composition and cell counting in tissue volumes can only be approximated due to characteristics of tissue sectioning, including incomplete sampling and the constraints of 2D imaging of 5 micron thick tissue slabs. We have used a small, vertebrate organism, the zebrafish, to test the potential of microCT for systematic macroscopic and microscopic morphological phenotyping. While cell resolution is routinely achieved using methods such as light sheet fluorescence microscopy and optical tomography, these methods do not provide the pancellular perspective characteristic of histology, and are constrained by the limited penetration of visible light through pigmented and opaque specimens, as characterizes zebrafish juveniles. Here, we provide an example of neuroanatomy that can be studied by microCT of stained soft tissue at 1.43 micron isotropic voxel resolution. We conclude that synchrotron microCT is a form of 3D imaging that may potentially be adopted towards more reproducible, large-scale, morphological phenotyping of optically opaque tissues. Further development of soft tissue microCT, visualization and quantitative tools will enhance its utility.
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Affiliation(s)
- Xuying Xin
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033, USA.,Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.,Penn State Consortium for Interdisciplinary Image Informatics and Visualization, USA
| | - Darin Clark
- Center for In Vivo Microscopy, Department of Radiology, Duke University Medical Center, Durham, NC 27708, USA
| | - Khai Chung Ang
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033, USA.,Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.,Penn State Consortium for Interdisciplinary Image Informatics and Visualization, USA
| | - Damian B van Rossum
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033, USA.,Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.,Penn State Consortium for Interdisciplinary Image Informatics and Visualization, USA
| | - Jean Copper
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033, USA.,Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.,Penn State Consortium for Interdisciplinary Image Informatics and Visualization, USA
| | - Xianghui Xiao
- Advanced Photon Source, Argonne National Laboratory Argonne, IL 60439, USA
| | | | - Keith C Cheng
- Department of Pathology, Penn State College of Medicine, Hershey, PA 17033, USA.,Jake Gittlen Laboratories for Cancer Research, Hershey, PA 17033, USA.,Penn State Consortium for Interdisciplinary Image Informatics and Visualization, USA
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9
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Jegla T, Nguyen MM, Feng C, Goetschius DJ, Luna E, van Rossum DB, Kamel B, Pisupati A, Milner ES, Rolls MM. Bilaterian Giant Ankyrins Have a Common Evolutionary Origin and Play a Conserved Role in Patterning the Axon Initial Segment. PLoS Genet 2016; 12:e1006457. [PMID: 27911898 PMCID: PMC5135030 DOI: 10.1371/journal.pgen.1006457] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 11/03/2016] [Indexed: 12/03/2022] Open
Abstract
In vertebrate neurons, the axon initial segment (AIS) is specialized for action potential initiation. It is organized by a giant 480 Kd variant of ankyrin G (AnkG) that serves as an anchor for ion channels and is required for a plasma membrane diffusion barrier that excludes somatodendritic proteins from the axon. An unusually long exon required to encode this 480Kd variant is thought to have been inserted only recently during vertebrate evolution, so the giant ankyrin-based AIS scaffold has been viewed as a vertebrate adaptation for fast, precise signaling. We re-examined AIS evolution through phylogenomic analysis of ankyrins and by testing the role of ankyrins in proximal axon organization in a model multipolar Drosophila neuron (ddaE). We find giant isoforms of ankyrin in all major bilaterian phyla, and present evidence in favor of a single common origin for giant ankyrins and the corresponding long exon in a bilaterian ancestor. This finding raises the question of whether giant ankyrin isoforms play a conserved role in AIS organization throughout the Bilateria. We examined this possibility by looking for conserved ankyrin-dependent AIS features in Drosophila ddaE neurons via live imaging. We found that ddaE neurons have an axonal diffusion barrier proximal to the cell body that requires a giant isoform of the neuronal ankyrin Ank2. Furthermore, the potassium channel shal concentrates in the proximal axon in an Ank2-dependent manner. Our results indicate that the giant ankyrin-based cytoskeleton of the AIS may have evolved prior to the radiation of extant bilaterian lineages, much earlier than previously thought. The axon initial segment (AIS) is currently thought to be a distinguishing feature of vertebrate neurons that adapts them for rapid, precise signaling. It serves as a hub for the regulation of neuronal excitability as the site of action potential initiation and also acts as the boundary between the highly-specialized axon and the rest of the cell. Here we show that the giant ankyrins that structurally organize the AIS, and were thought to be vertebrate-specific, instead have an ancient origin in a bilaterian ancestor. We further show the presence of a giant ankyrin-dependent AIS-like plasma membrane boundary between the axon and soma in a Drosophila sensory neuron. These results suggest that the cytoskeletal backbone for the AIS is not unique to vertebrates, but instead may be an evolutionarily conserved feature of bilaterian neurons.
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Affiliation(s)
- Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (MMR); (TJ)
| | - Michelle M. Nguyen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Chengye Feng
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Daniel J. Goetschius
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Esteban Luna
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Damian B. van Rossum
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Bishoy Kamel
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Aditya Pisupati
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Elliott S. Milner
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Melissa M. Rolls
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (MMR); (TJ)
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10
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Chintapalli SV, Jayanthi S, Mallipeddi PL, Gundampati R, Suresh Kumar TK, van Rossum DB, Anishkin A, Adams SH. Novel Molecular Interactions of Acylcarnitines and Fatty Acids with Myoglobin. J Biol Chem 2016; 291:25133-25143. [PMID: 27758871 DOI: 10.1074/jbc.m116.754978] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 09/29/2016] [Indexed: 11/06/2022] Open
Abstract
Previous research has indicated that long-chain fatty acids can bind myoglobin (Mb) in an oxygen-dependent manner. This suggests that oxy-Mb may play an important role in fuel delivery in Mb-rich muscle fibers (e.g. type I fibers and cardiomyocytes), and raises the possibility that Mb also serves as an acylcarnitine-binding protein. We report for the first time the putative interaction and affinity characteristics for different chain lengths of both fatty acids and acylcarnitines with oxy-Mb using molecular dynamic simulations and isothermal titration calorimetry experiments. We found that short- to medium-chain fatty acids or acylcarnitines (ranging from C2:0 to C10:0) fail to achieve a stable conformation with oxy-Mb. Furthermore, our results indicate that C12:0 is the minimum chain length essential for stable binding of either fatty acids or acylcarnitines with oxy-Mb. Importantly, the empirical lipid binding studies were consistent with structural modeling. These results reveal that: (i) the lipid binding affinity for oxy-Mb increases as the chain length increases (i.e. C12:0 to C18:1), (ii) the binding affinities of acylcarnitines are higher when compared with their respective fatty acid counterparts, and (iii) both fatty acids and acylcarnitines bind to oxy-Mb in 1:1 stoichiometry. Taken together, our results support a model in which oxy-Mb is a novel regulator of long-chain acylcarnitine and fatty acid pools in Mb-rich tissues. This has important implications for physiological fuel management during exercise, and relevance to pathophysiological conditions (e.g. fatty acid oxidation disorders and cardiac ischemia) where long-chain acylcarnitine accumulation is evident.
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Affiliation(s)
- Sree V Chintapalli
- From the Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202,
| | - Srinivas Jayanthi
- the Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
| | - Prema L Mallipeddi
- the Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204
| | - Ravikumar Gundampati
- the Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
| | | | - Damian B van Rossum
- the Center for Computational Proteomics and.,the Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Andriy Anishkin
- the Department of Biology, University of Maryland, College Park, Maryland 20742
| | - Sean H Adams
- From the Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202,
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11
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Li X, Anishkin A, Liu H, van Rossum DB, Chintapalli SV, Sassic JK, Gallegos D, Pivaroff-Ward K, Jegla T. Bimodal regulation of an Elk subfamily K+ channel by phosphatidylinositol 4,5-bisphosphate. ACTA ACUST UNITED AC 2016; 146:357-74. [PMID: 26503718 PMCID: PMC4621751 DOI: 10.1085/jgp.201511491] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PIP2 mediates the bimodal regulation of the EAG family K+ channel ELK1 to produce an overall inhibitory effect. Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates Shaker K+ channels and voltage-gated Ca2+ channels in a bimodal fashion by inhibiting voltage activation while stabilizing open channels. Bimodal regulation is conserved in hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, but voltage activation is enhanced while the open channel state is destabilized. The proposed sites of PIP2 regulation in these channels include the voltage-sensor domain (VSD) and conserved regions of the proximal cytoplasmic C terminus. Relatively little is known about PIP2 regulation of Ether-á-go-go (EAG) channels, a metazoan-specific family of K+ channels that includes three gene subfamilies, Eag (Kv10), Erg (Kv11), and Elk (Kv12). We examined PIP2 regulation of the Elk subfamily potassium channel human Elk1 to determine whether bimodal regulation is conserved within the EAG K+ channel family. Open-state stabilization by PIP2 has been observed in human Erg1, but the proposed site of regulation in the distal C terminus is not conserved among EAG family channels. We show that PIP2 strongly inhibits voltage activation of Elk1 but also stabilizes the open state. This stabilization produces slow deactivation and a mode shift in voltage gating after activation. However, removal of PIP2 has the net effect of enhancing Elk1 activation. R347 in the linker between the VSD and pore (S4–S5 linker) and R479 near the S6 activation gate are required for PIP2 to inhibit voltage activation. The ability of PIP2 to stabilize the open state also requires these residues, suggesting an overlap in sites central to the opposing effects of PIP2 on channel gating. Open-state stabilization in Elk1 requires the N-terminal eag domain (PAS domain + Cap), and PIP2-dependent stabilization is enhanced by a conserved basic residue (K5) in the Cap. Our data shows that PIP2 can bimodally regulate voltage gating in EAG family channels, as has been proposed for Shaker and HCN channels. PIP2 regulation appears fundamentally different for Elk and KCNQ channels, suggesting that, although both channel types can regulate action potential threshold in neurons, they are not functionally redundant.
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Affiliation(s)
- Xiaofan Li
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD 20742
| | - Hansi Liu
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Damian B van Rossum
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Sree V Chintapalli
- Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202 Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202
| | - Jessica K Sassic
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - David Gallegos
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Kendra Pivaroff-Ward
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195
| | - Timothy Jegla
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
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12
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Baker EC, Layden MJ, van Rossum DB, Kamel B, Medina M, Simpson E, Jegla T. Functional Characterization of Cnidarian HCN Channels Points to an Early Evolution of Ih. PLoS One 2015; 10:e0142730. [PMID: 26555239 PMCID: PMC4640657 DOI: 10.1371/journal.pone.0142730] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/26/2015] [Indexed: 11/24/2022] Open
Abstract
HCN channels play a unique role in bilaterian physiology as the only hyperpolarization-gated cation channels. Their voltage-gating is regulated by cyclic nucleotides and phosphatidylinositol 4,5-bisphosphate (PIP2). Activation of HCN channels provides the depolarizing current in response to hyperpolarization that is critical for intrinsic rhythmicity in neurons and the sinoatrial node. Additionally, HCN channels regulate dendritic excitability in a wide variety of neurons. Little is known about the early functional evolution of HCN channels, but the presence of HCN sequences in basal metazoan phyla and choanoflagellates, a protozoan sister group to the metazoans, indicate that the gene family predates metazoan emergence. We functionally characterized two HCN channel orthologs from Nematostella vectensis (Cnidaria, Anthozoa) to determine which properties of HCN channels were established prior to the emergence of bilaterians. We find Nematostella HCN channels share all the major functional features of bilaterian HCNs, including reversed voltage-dependence, activation by cAMP and PIP2, and block by extracellular Cs+. Thus bilaterian-like HCN channels were already present in the common parahoxozoan ancestor of bilaterians and cnidarians, at a time when the functional diversity of voltage-gated K+ channels was rapidly expanding. NvHCN1 and NvHCN2 are expressed broadly in planulae and in both the endoderm and ectoderm of juvenile polyps.
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Affiliation(s)
- Emma C. Baker
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Michael J. Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - Damian B. van Rossum
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
- Huck Institutes of the Life Sciences, University Park, Pennsylvania, United States of America
| | - Bishoy Kamel
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Monica Medina
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
| | - Eboni Simpson
- Penn State University Graduate School, Summer Research Opportunities Program (SROP), University Park, Pennsylvania, United States of America
| | - Timothy Jegla
- Department of Biology, Penn State University, University Park, Pennsylvania, United States of America
- Huck Institutes of the Life Sciences, University Park, Pennsylvania, United States of America
- * E-mail:
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13
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Chintapalli SV, Bhardwaj G, Patel R, Shah N, Patterson RL, van Rossum DB, Anishkin A, Adams SH. Molecular dynamic simulations reveal the structural determinants of Fatty Acid binding to oxy-myoglobin. PLoS One 2015; 10:e0128496. [PMID: 26030763 PMCID: PMC4451517 DOI: 10.1371/journal.pone.0128496] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 04/27/2015] [Indexed: 11/18/2022] Open
Abstract
The mechanism(s) by which fatty acids are sequestered and transported in muscle have not been fully elucidated. A potential key player in this process is the protein myoglobin (Mb). Indeed, there is a catalogue of empirical evidence supporting direct interaction of globins with fatty acid metabolites; however, the binding pocket and regulation of the interaction remains to be established. In this study, we employed a computational strategy to elucidate the structural determinants of fatty acids (palmitic & oleic acid) binding to Mb. Sequence analysis and docking simulations with a horse (Equus caballus) structural Mb reference reveals a fatty acid-binding site in the hydrophobic cleft near the heme region in Mb. Both palmitic acid and oleic acid attain a "U" shaped structure similar to their conformation in pockets of other fatty acid-binding proteins. Specifically, we found that the carboxyl head group of palmitic acid coordinates with the amino group of Lys45, whereas the carboxyl group of oleic acid coordinates with both the amino groups of Lys45 and Lys63. The alkyl tails of both fatty acids are supported by surrounding hydrophobic residues Leu29, Leu32, Phe33, Phe43, Phe46, Val67, Val68 and Ile107. In the saturated palmitic acid, the hydrophobic tail moves freely and occasionally penetrates deeper inside the hydrophobic cleft, making additional contacts with Val28, Leu69, Leu72 and Ile111. Our simulations reveal a dynamic and stable binding pocket in which the oxygen molecule and heme group in Mb are required for additional hydrophobic interactions. Taken together, these findings support a mechanism in which Mb acts as a muscle transporter for fatty acid when it is in the oxygenated state and releases fatty acid when Mb converts to deoxygenated state.
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Affiliation(s)
- Sree V. Chintapalli
- Arkansas Children’s Nutrition Center, and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail: (SVC); (SHA)
| | - Gaurav Bhardwaj
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Reema Patel
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Natasha Shah
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Randen L. Patterson
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
| | - Damian B. van Rossum
- Center for Computational Proteomics, The Pennsylvania State University, State College, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, State College, Pennsylvania, United States of America
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, Maryland, United States of America
| | - Sean H. Adams
- Arkansas Children’s Nutrition Center, and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail: (SVC); (SHA)
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14
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Hedgepeth SC, Garcia MI, Wagner LE, Rodriguez AM, Chintapalli SV, Snyder RR, Hankins GDV, Henderson BR, Brodie KM, Yule DI, van Rossum DB, Boehning D. The BRCA1 tumor suppressor binds to inositol 1,4,5-trisphosphate receptors to stimulate apoptotic calcium release. J Biol Chem 2015; 290:7304-13. [PMID: 25645916 DOI: 10.1074/jbc.m114.611186] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The inositol 1,4,5-trisphosphate receptor (IP3R) is a ubiquitously expressed endoplasmic reticulum (ER)-resident calcium channel. Calcium release mediated by IP3Rs influences many signaling pathways, including those regulating apoptosis. IP3R activity is regulated by protein-protein interactions, including binding to proto-oncogenes and tumor suppressors to regulate cell death. Here we show that the IP3R binds to the tumor suppressor BRCA1. BRCA1 binding directly sensitizes the IP3R to its ligand, IP3. BRCA1 is recruited to the ER during apoptosis in an IP3R-dependent manner, and, in addition, a pool of BRCA1 protein is constitutively associated with the ER under non-apoptotic conditions. This is likely mediated by a novel lipid binding activity of the first BRCA1 C terminus domain of BRCA1. These findings provide a mechanistic explanation by which BRCA1 can act as a proapoptotic protein.
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Affiliation(s)
- Serena C Hedgepeth
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030, the Cell Biology Graduate Program and
| | - M Iveth Garcia
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030, the Cell Biology Graduate Program and
| | - Larry E Wagner
- the Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - Ana M Rodriguez
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Sree V Chintapalli
- the Department of Biology, Penn State University, University Park, Pennsylvania, 16802, and
| | - Russell R Snyder
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Gary D V Hankins
- the Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Beric R Henderson
- the Centre for Cancer Research, Westmead Millennium Institute at Westmead Hospital, The University of Sydney, Westmead, New South Wales 2145, Australia
| | - Kirsty M Brodie
- the Centre for Cancer Research, Westmead Millennium Institute at Westmead Hospital, The University of Sydney, Westmead, New South Wales 2145, Australia
| | - David I Yule
- the Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642
| | - Damian B van Rossum
- the Department of Biology, Penn State University, University Park, Pennsylvania, 16802, and
| | - Darren Boehning
- From the Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, Texas 77030,
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15
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Lindy AS, Parekh PK, Zhu R, Kanju P, Chintapalli SV, Tsvilovskyy V, Patterson RL, Anishkin A, van Rossum DB, Liedtke WB. TRPV channel-mediated calcium transients in nociceptor neurons are dispensable for avoidance behaviour. Nat Commun 2014; 5:4734. [PMID: 25178952 PMCID: PMC4164786 DOI: 10.1038/ncomms5734] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 07/17/2014] [Indexed: 12/21/2022] Open
Abstract
Animals need to sense and react to potentially dangerous environments. TRP ion channels participate in nociception, presumably via Ca2+ influx, in most animal species. However, the relationship between ion permeation and animals’ nocifensive behaviour is unknown. Here we use an invertebrate animal model with relevance for mammalian pain. We analyse the putative selectivity filter of OSM-9, a TRPV channel, in osmotic avoidance behaviour of Caenorhabditis elegans. Using mutagenized OSM-9 expressed in the head nociceptor neuron, ASH, we study nocifensive behaviour and Ca2+ influx. Within the selectivity filter, M601-F609, Y604G strongly reduces avoidance behaviour and eliminates Ca2+ transients. Y604F also abolishes Ca2+ transients in ASH, while sustaining avoidance behaviour, yet it disrupts behavioral plasticity. Homology modelling of the OSM-9 pore suggests that Y604 may assume a scaffolding role. Thus, aromatic residues in the OSM-9 selectivity filter are critical for pain behaviour and ion permeation. These findings have relevance for understanding evolutionary roots of mammalian nociception. TRPs are calcium-permeable channels involved in the sensing of damaging stimuli but the relationship between calcium influx and pain behaviour has been elusive. Here the authors find that the TRP channel OSM-9 functions as an ion channel in vivo in C. elegans, and establish residues that are critical for worm pain-like behaviour.
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Affiliation(s)
- Amanda S Lindy
- 1] Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Puja K Parekh
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Richard Zhu
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Patrick Kanju
- Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Sree V Chintapalli
- 1] Department of Membrane Biology and Physiology, University of California, Davis, California 95616, USA [2] Department of Biochemistry and Molecular Medicine, University of California, Davis, California 95616, USA
| | - Volodymyr Tsvilovskyy
- Department of Pharmacology, University of Heidelberg, Im Neuenheimer Feld 366, 69120 Heidelberg, Germany
| | - Randen L Patterson
- 1] Department of Membrane Biology and Physiology, University of California, Davis, California 95616, USA [2] Department of Biochemistry and Molecular Medicine, University of California, Davis, California 95616, USA
| | - Andriy Anishkin
- 1] Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania 16801, USA [2] Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA
| | - Damian B van Rossum
- 1] Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania 16801, USA [2] Department of Biology, The Pennsylvania State University, University Park, Pennsylvania 16801, USA
| | - Wolfgang B Liedtke
- 1] Department of Neurology, Duke University Medical Center, Durham, North Carolina 27710, USA [2] Duke University Clinics for Pain and Palliative Care, 932 Morreene Road, Durham, North Carolina 27705, USA [3] Departments of Anesthesiology and Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA [4] Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA
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16
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Whelan JN, Tran KC, Cox RR, van Rossum DB, Patterson RL, Teng M. Exploitation Of The Host Ubiquitin System By Respiratory Syncytial Virus Nonstructural Protein 2. J Allergy Clin Immunol 2014. [DOI: 10.1016/j.jaci.2013.12.1004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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17
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Chintapalli SV, Bhardwaj G, Babu J, Hadjiyianni L, Hong Y, Todd GK, Boosalis CA, Zhang Z, Zhou X, Ma H, Anishkin A, van Rossum DB, Patterson RL. Reevaluation of the evolutionary events within recA/RAD51 phylogeny. BMC Genomics 2013; 14:240. [PMID: 23574621 PMCID: PMC3637515 DOI: 10.1186/1471-2164-14-240] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 02/28/2013] [Indexed: 11/20/2022] Open
Abstract
Background The recA/RAD51 gene family encodes a diverse set of recombinase proteins that affect homologous recombination, DNA-repair, and genome stability. The recA gene family is expressed across all three domains of life - Eubacteria, Archaea, and Eukaryotes - and even in some viruses. To date, efforts to resolve the deep evolutionary origins of this ancient protein family have been hindered by the high sequence divergence between paralogous groups (i.e. ~30% average pairwise identity). Results Through large taxon sampling and the use of a phylogenetic algorithm designed for inferring evolutionary events in highly divergent paralogs, we obtained a robust, parsimonious and more refined phylogenetic history of the recA/RAD51 superfamily. Conclusions In summary, our model for the evolution of recA/RAD51 family provides a better understanding of the ancient origin of recA proteins and the multiple events that lead to the diversification of recA homologs in eukaryotes, including the discovery of additional RAD51 sub-families.
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Affiliation(s)
- Sree V Chintapalli
- Department of Physiology and Membrane Biology, School of Medicine, University of California-Davis, CA, USA
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Bhardwaj G, Ko KD, Hong Y, Zhang Z, Ho NL, Chintapalli SV, Kline LA, Gotlin M, Hartranft DN, Patterson ME, Dave F, Smith EJ, Holmes EC, Patterson RL, van Rossum DB. PHYRN: a robust method for phylogenetic analysis of highly divergent sequences. PLoS One 2012; 7:e34261. [PMID: 22514627 PMCID: PMC3325999 DOI: 10.1371/journal.pone.0034261] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/24/2012] [Indexed: 11/19/2022] Open
Abstract
Both multiple sequence alignment and phylogenetic analysis are problematic in the "twilight zone" of sequence similarity (≤ 25% amino acid identity). Herein we explore the accuracy of phylogenetic inference at extreme sequence divergence using a variety of simulated data sets. We evaluate four leading multiple sequence alignment (MSA) methods (MAFFT, T-COFFEE, CLUSTAL, and MUSCLE) and six commonly used programs of tree estimation (Distance-based: Neighbor-Joining; Character-based: PhyML, RAxML, GARLI, Maximum Parsimony, and Bayesian) against a novel MSA-independent method (PHYRN) described here. Strikingly, at "midnight zone" genetic distances (~7% pairwise identity and 4.0 gaps per position), PHYRN returns high-resolution phylogenies that outperform traditional approaches. We reason this is due to PHRYN's capability to amplify informative positions, even at the most extreme levels of sequence divergence. We also assess the applicability of the PHYRN algorithm for inferring deep evolutionary relationships in the divergent DANGER protein superfamily, for which PHYRN infers a more robust tree compared to MSA-based approaches. Taken together, these results demonstrate that PHYRN represents a powerful mechanism for mapping uncharted frontiers in highly divergent protein sequence data sets.
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Affiliation(s)
- Gaurav Bhardwaj
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
| | - Kyung Dae Ko
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Yoojin Hong
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Zhenhai Zhang
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Ngai Lam Ho
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sree V. Chintapalli
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
| | - Lindsay A. Kline
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew Gotlin
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - David Nicholas Hartranft
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Morgen E. Patterson
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Foram Dave
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Evan J. Smith
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Edward C. Holmes
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Randen L. Patterson
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Davis, California, United States of America
- Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America
- Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
| | - Damian B. van Rossum
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Center for Translational Bioscience and Computing, University of California Davis, Davis, California, United States of America
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Ko KD, Bhardwaj G, Hong Y, Chang GS, Kiselyov K, van Rossum DB, Patterson RL. Phylogenetic profiles reveal structural/functional determinants of TRPC3 signal-sensing antennae. Commun Integr Biol 2011; 2:133-7. [PMID: 19704910 DOI: 10.4161/cib.7746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Accepted: 01/02/2009] [Indexed: 11/19/2022] Open
Abstract
Biochemical assessment of channel structure/function is incredibly challenging. Developing computational tools that provide these data would enable translational research, accelerating mechanistic experimentation for the bench scientist studying ion channels. Starting with the premise that protein sequence encodes information about structure, function and evolution (SF&E), we developed a unified framework for inferring SF&E from sequence information using a knowledge-based approach. The Gestalt Domain Detection Algorithm-Basic Local Alignment Tool (GDDA-BLAST) provides phylogenetic profiles that can model, ab initio, SF&E relationships of biological sequences at the whole protein, single domain and single-amino acid level.1,2 In our recent paper,4 we have applied GDDA-BLAST analysis to study canonical TRP (TRPC) channels1 and empirically validated predicted lipid-binding and trafficking activities contained within the TRPC3 TRP_2 domain of unknown function. Overall, our in silico, in vitro, and in vivo experiments support a model in which TRPC3 has signal-sensing antennae which are adorned with lipid-binding, trafficking and calmodulin regulatory domains. In this Addendum, we correlate our functional domain analysis with the cryo-EM structure of TRPC3.3 In addition, we synthesize recent studies with our new findings to provide a refined model on the mechanism(s) of TRPC3 activation/deactivation.
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Affiliation(s)
- Kyung Dae Ko
- Department of Biology; The Pennsylvania State University; University Park; PA USA
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Abstract
A major computational challenge in the genomic era is annotating structure/function to the vast quantities of sequence information that is now available. This problem is illustrated by the fact that most proteins lack comprehensive annotations, even when experimental evidence exists. We previously theorized that embedded-alignment profiles (simply "alignment profiles" hereafter) provide a quantitative method that is capable of relating the structural and functional properties of proteins, as well as their evolutionary relationships. A key feature of alignment profiles lies in the interoperability of data format (e.g., alignment information, physio-chemical information, genomic information, etc.). Indeed, we have demonstrated that the Position Specific Scoring Matrices (PSSMs) are an informative M-dimension that is scored by quantitatively measuring the embedded or unmodified sequence alignments. Moreover, the information obtained from these alignments is informative, and remains so even in the "twilight zone" of sequence similarity (<25% identity). Although our previous embedding strategy was powerful, it suffered from contaminating alignments (embedded AND unmodified) and high computational costs. Herein, we describe the logic and algorithmic process for a heuristic embedding strategy named "Adaptive GDDA-BLAST." Adaptive GDDA-BLAST is, on average, up to 19 times faster than, but has similar sensitivity to our previous method. Further, data are provided to demonstrate the benefits of embedded-alignment measurements in terms of detecting structural homology in highly divergent protein sequences and isolating secondary structural elements of transmembrane and ankyrin-repeat domains. Together, these advances allow further exploration of the embedded alignment data space within sufficiently large data sets to eventually induce relevant statistical inferences. We show that sequence embedding could serve as one of the vehicles for measurement of low-identity alignments and for incorporation thereof into high-performance PSSM-based alignment profiles.
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Affiliation(s)
- Yoojin Hong
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jaewoo Kang
- Department of Computer Science and Engineering, Korea University, Seoul, Korea
- Department of Biostatistics, College of Medicine, Korea University, Seoul, Korea
| | - Dongwon Lee
- Department of Computer Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- College of Information Sciences and Technology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Damian B. van Rossum
- Center for Computational Proteomics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
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Hoque KM, Woodward OM, van Rossum DB, Zachos NC, Chen L, Leung GPH, Guggino WB, Guggino SE, Tse CM. Epac1 mediates protein kinase A-independent mechanism of forskolin-activated intestinal chloride secretion. ACTA ACUST UNITED AC 2010; 135:43-58. [PMID: 20038525 PMCID: PMC2806414 DOI: 10.1085/jgp.200910339] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Intestinal Cl− secretion is stimulated by cyclic AMP (cAMP) and intracellular calcium ([Ca2+]i). Recent studies show that protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac) are downstream targets of cAMP. Therefore, we tested whether both PKA and Epac are involved in forskolin (FSK)/cAMP-stimulated Cl− secretion. Human intestinal T84 cells and mouse small intestine were used for short circuit current (Isc) measurement in response to agonist-stimulated Cl− secretion. FSK-stimulated Cl− secretion was completely inhibited by the additive effects of the PKA inhibitor, H89 (1 µM), and the [Ca2+]i chelator, 1,2-bis-(o-aminophenoxy)-ethane-N,N,N’,N’-tetraacetic acid, tetraacetoxymethyl ester (BAPTA-AM; 25 µM). Both FSK and the Epac activator 8-pCPT-2’-O-Me-cAMP (50 µM) elevated [Ca2+]i, activated Ras-related protein 2, and induced Cl− secretion in intact or basolateral membrane–permeabilized T84 cells and mouse ileal sheets. The effects of 8-pCPT-2’-O-Me-cAMP were completely abolished by BAPTA-AM, but not by H89. In contrast, T84 cells with silenced Epac1 had a reduced Isc response to FSK, and this response was completely inhibited by H89, but not by the phospholipase C inhibitor U73122 or BAPTA-AM. The stimulatory effect of 8-pCPT-2’-O-Me-cAMP on Cl− secretion was not abolished by cystic fibrosis transmembrane conductance (CFTR) inhibitor 172 or glibenclamide, suggesting that CFTR channels are not involved. This was confirmed by lack of effect of 8-pCPT-2’-O-Me-cAMP on whole cell patch clamp recordings of CFTR currents in Chinese hamster ovary cells transiently expressing the human CFTR channel. Furthermore, biophysical characterization of the Epac1-dependent Cl− conductance of T84 cells mounted in Ussing chambers suggested that this conductance was hyperpolarization activated, inwardly rectifying, and displayed a Cl−>Br−>I− permeability sequence. These results led us to conclude that the Epac-Rap-PLC-[Ca2+]i signaling pathway is involved in cAMP-stimulated Cl− secretion, which is carried by a novel, previously undescribed Cl− channel.
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Affiliation(s)
- Kazi Mirajul Hoque
- Department of Medicine, GI Division, Johns Hopkins University, Baltimore, MD 21205, USA
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Hoque KM, Woodward OM, van Rossum DB, Zachos NC, Chen L, Leung GP, Guggino WB, Guggino SE, Tse CM. Epac1 mediates protein kinase A–independent mechanism of forskolin-activated intestinal chloride secretion. J Biophys Biochem Cytol 2009. [DOI: 10.1083/jcb1877oia18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Zachos NC, van Rossum DB, Li X, Caraveo G, Sarker R, Cha B, Mohan S, Desiderio S, Patterson RL, Donowitz M. Phospholipase C-gamma binds directly to the Na+/H+ exchanger 3 and is required for calcium regulation of exchange activity. J Biol Chem 2009; 284:19437-44. [PMID: 19473983 DOI: 10.1074/jbc.m109.006098] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Multiple studies suggest that phospholipase C-gamma (PLC-gamma) contributes to regulation of sodium/hydrogen exchanger 3 (NHE3) in the small intestine, although the mechanism(s) for this regulation remain unknown. We demonstrate here that PLC-gamma binds directly to the C terminus of NHE3 and exists in similar sized multiprotein complexes as NHE3. This binding is dynamic and decreases with elevated [Ca(2+)](i). The PLC-gamma-binding site in NHE3 was identified (amino acids 586-605) and shown to be a critical regulatory domain for protein complex formation, because when it is mutated, NHE3 binding to PLC-gamma as well as NHERF2 is lost. An inhibitory peptide, which binds to the Src homology 2 domains contained in PLC-gamma without interrupting binding of PLC-gamma to NHE3, was used to probe a non-lipase-dependent role of PLC-gamma. In the presence of this peptide, carbachol-stimulated calcium inhibition of NHE3 was lost. These results mirror previous studies with the transient receptor potential channel and suggest that PLC-gamma may play a common role in regulating the cell-surface expression of ion transporters.
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Affiliation(s)
- Nicholas C Zachos
- Division of Gastroenterology and Hepatology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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van Rossum DB, Patterson RL. PKC and PLA2: probing the complexities of the calcium network. Cell Calcium 2009; 45:535-45. [PMID: 19345415 DOI: 10.1016/j.ceca.2009.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Revised: 02/24/2009] [Accepted: 02/26/2009] [Indexed: 11/15/2022]
Abstract
Lipid signaling and phosphorylation cascades are fundamental to calcium signaling networks. In this review, we will discuss the recent laboratory findings for the phospholipase A(2) (PLA(2))/protein kinase C (PKC) pathway within cellular calcium networks. The complexity and connectivity of these ubiquitous cellular signals make interpretation of experimental results extremely challenging. We present here computational methods which have been developed to conquer such complex data, and how they can be used to make models capable of accurately predicting cellular responses within multiple calcium signaling pathways. We propose that information obtained from network analysis and computational techniques provides a rich source of knowledge which can be directly translated to the laboratory benchtop.
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Affiliation(s)
- Damian B van Rossum
- Department of Biology, The Pennsylvania State University, PA, United States.
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Hong Y, Chalkia D, Ko KD, Bhardwaj G, Chang GS, van Rossum DB, Patterson RL. Phylogenetic Profiles Reveal Structural and Functional Determinants of Lipid-binding. ACTA ACUST UNITED AC 2009; 2:139-149. [PMID: 19946567 DOI: 10.4172/jpb.1000071] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the major challenges in the genomic era is annotating structure/function to the vast quantities of sequence information now available. Indeed, most of the protein sequence database lacks comprehensive annotation, even when experimental evidence exists. Further, within structurally resolved and functionally annotated protein domains, additional functionalities contained in these domains are not apparent. To add further complication, small changes in the amino-acid sequence can lead to profound changes in both structure and function, underscoring the need for rapid and reliable methods to analyze these types of data. Phylogenetic profiles provide a quantitative method that can relate the structural and functional properties of proteins, as well as their evolutionary relationships. Using all of the structurally resolved Src-Homology-2 (SH2) domains, we demonstrate that knowledge-bases can be used to create single-amino acid phylogenetic profiles which reliably annotate lipid-binding. Indeed, these measures isolate the known phosphotyrosine and hydrophobic pockets as integral to lipid-binding function. In addition, we determined that the SH2 domain of Tec family kinases bind to lipids with varying affinity and specificity. Simulating mutations in Bruton's tyrosine kinase (BTK) that cause X-Linked Agammaglobulinemia (XLA) predict that these mutations alter lipid-binding, which we confirm experimentally. In light of these results, we propose that XLA-causing mutations in the SH3-SH2 domain of BTK alter lipid-binding, which could play a causative role in the XLA-phenotype. Overall, our study suggests that the number of lipid-binding proteins is drastically underestimated and, with further development, phylogenetic profiles can provide a method for rapidly increasing the functional annotation of protein sequences.
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Affiliation(s)
- Yoojin Hong
- Center for Computational Proteomics, The Pennsylvania State University
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27
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van Rossum DB, Oberdick D, Rbaibi Y, Bhardwaj G, Barrow RK, Nikolaidis N, Snyder SH, Kiselyov K, Patterson RL. TRP_2, a lipid/trafficking domain that mediates diacylglycerol-induced vesicle fusion. J Biol Chem 2008; 283:34384-92. [PMID: 19043047 DOI: 10.1074/jbc.m804707200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently modeled transient receptor potential (TRP) channels using the Gestalt Domain Detection Algorithm-Basic Local Alignment Tool (GDDA-BLAST), which derives structural, functional, and evolutionary information from primary amino acid sequences using phylogenetic profiles ( Ko, K. D., Hong, Y., Chang, G. S., Bhardwaj, G., van Rossum, D. B., and Patterson, R. L. (2008) Physics Arch. Quant. Methods arXiv: 0806.2394v1 ). Herein we test our functional predictions for the TRP_2 domain of TRPC3; a domain of unknown function that is conserved in all TRPC channels. Our functional models of this domain identify both lipid binding and trafficking activities. In this study, we reveal: (i) a novel structural determinant of ion channel sensitivity to lipids, (ii) a molecular mechanism for the difference between diacylglycerol (DAG)-sensitive and DAG-insensitive TRPC subfamilies, and (iii) evidence that TRPC3 can comprise part of the vesicle fusion machinery. Indeed, the TRPC3 TRP_2 domain mediates channel trafficking to the plasma membrane and binds to plasma membrane lipids. Further, mutations in TRP_2, which alter lipid binding, also disrupt the DAG-mediated fusion of TRPC3-containing vesicles with the plasma membrane without disrupting SNARE interactions. Importantly, these data agree with the known role of DAG in membrane destabilization, which facilitates SNARE-dependent synaptic vesicle fusion ( Villar, A. V., Goni, F. M., and Alonso, A. (2001) FEBS Lett. 494, 117-120 and Goni, F. M., and Alonso, A. (1999) Prog. Lipid Res. 38, 1-48 ). Taken together, functional models generated by GDDA-BLAST provide a computational platform for deriving domain functionality, which can have in vivo and mechanistic relevance.
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Affiliation(s)
- Damian B van Rossum
- Center for Computational Proteomics and Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Nikolaidis N, Chalkia D, Watkins DN, Barrow RK, Snyder SH, van Rossum DB, Patterson RL. Ancient origin of the new developmental superfamily DANGER. PLoS One 2007; 2:e204. [PMID: 17301879 PMCID: PMC1784063 DOI: 10.1371/journal.pone.0000204] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 01/14/2007] [Indexed: 01/15/2023] Open
Abstract
Developmental proteins play a pivotal role in the origin of animal complexity and diversity. We report here the identification of a highly divergent developmental protein superfamily (DANGER), which originated before the emergence of animals (∼850 million years ago) and experienced major expansion-contraction events during metazoan evolution. Sequence analysis demonstrates that DANGER proteins diverged via multiple mechanisms, including amino acid substitution, intron gain and/or loss, and recombination. Divergence for DANGER proteins is substantially greater than for the prototypic member of the superfamily (Mab-21 family) and other developmental protein families (e.g., WNT proteins). DANGER proteins are widely expressed and display species-dependent tissue expression patterns, with many members having roles in development. DANGER1A, which regulates the inositol trisphosphate receptor, promotes the differentiation and outgrowth of neuronal processes. Regulation of development may be a universal function of DANGER family members. This family provides a model system to investigate how rapid protein divergence contributes to morphological complexity.
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Affiliation(s)
- Nikolas Nikolaidis
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * To whom correspondence should be addressed. E-mail: (RP); (NN)
| | - Dimitra Chalkia
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - D. Neil Watkins
- The Sidney Kimmel Cancer Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
| | - Roxanne K. Barrow
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
| | - Solomon H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, Maryland, United States of America
- Department of Pharmacology and Molecular Science, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Damian B. van Rossum
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Randen L. Patterson
- Biology Department, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * To whom correspondence should be addressed. E-mail: (RP); (NN)
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van Rossum DB, Patterson RL, Cheung KH, Barrow RK, Syrovatkina V, Gessell GS, Burkholder SG, Watkins DN, Foskett JK, Snyder SH. DANGER, a Novel Regulatory Protein of Inositol 1,4,5-Trisphosphate-Receptor Activity. J Biol Chem 2006; 281:37111-6. [PMID: 16990268 DOI: 10.1074/jbc.m608760200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We report the cloning and characterization of DANGER, a novel protein which physiologically binds to inositol 1,4,5-trisphosphate receptors (IP(3)R). DANGER is a membrane-associated protein predicted to contain a partial MAB-21 domain. It is expressed in a wide variety of neuronal cell lineages where it localizes to membranes in the cell periphery together with IP(3)R. DANGER interacts with IP(3)R in vitro and co-immunoprecipitates with IP(3)R from cellular preparations. DANGER robustly enhances Ca(2+)-mediated inhibition of IP(3) RCa(2+) release without affecting IP(3) binding in microsomal assays and inhibits gating in single-channel recordings of IP(3)R. DANGER appears to allosterically modulate the sensitivity of IP(3) RtoCa(2+) inhibition, which likely alters IP(3)R-mediated Ca(2+) dynamics in cells where DANGER and IP(3)R are co-expressed.
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Affiliation(s)
- Damian B van Rossum
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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30
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Abstract
TFII-I is a transcription factor and a target of phosphorylation by Bruton's tyrosine kinase. In humans, deletions spanning the TFII-I locus are associated with a cognitive defect, the Williams-Beuren cognitive profile. We report an unanticipated role of TFII-I outside the nucleus as a negative regulator of agonist-induced calcium entry (ACE) that suppresses surface accumulation of TRPC3 (transient receptor potential C3) channels. Inhibition of ACE by TFII-I requires phosphotyrosine residues that engage the SH2 (Src-homology 2) domains of phospholipase C-g (PLC-g) and an interrupted, pleckstrin homology (PH)-like domain that binds the split PH domain of PLC-g. Our observations suggest a model in which TFII-I suppresses ACE by competing with TRPC3 for binding to PLC-g.
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Affiliation(s)
- Gabriela Caraveo
- Department of Molecular Biology and Genetics, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Patterson RL, van Rossum DB, Nikolaidis N, Gill DL, Snyder SH. Phospholipase C-γ: diverse roles in receptor-mediated calcium signaling. Trends Biochem Sci 2005; 30:688-97. [PMID: 16260143 DOI: 10.1016/j.tibs.2005.10.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 08/23/2005] [Accepted: 10/13/2005] [Indexed: 01/25/2023]
Abstract
Ca2+ is a universal signal: the dynamic changes in its release and entry trigger a plethora of cellular responses. Central to this schema are members of the phospholipase C (PLC) superfamily, which relay information from the activated receptor to downstream signal cascades by production of second-messenger molecules. Recent studies reveal that, in addition to its enzymatic activity, PLC-gamma regulates Ca2+ entry via the formation of an intermolecular lipid-binding domain with canonical transient receptor potential 3 (TRPC3) ion channels. This complex, in turn, controls TRPC3 trafficking and cell-surface expression. Thus, TRPC3 ion channels are functionally linked to both lipase-dependent and -independent activities of PLC-gamma. Understanding the underlying molecular mechanisms that regulate this complex will probably clarify the processes of receptor-activated Ca2+ entry.
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Affiliation(s)
- Randen L Patterson
- Department of Biology, The Pennsylvania State University, Life Science Building, Shortlidge Road, University Park, PA 16801, USA
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van Rossum DB, Patterson RL, Sharma S, Barrow RK, Kornberg M, Gill DL, Snyder SH. Phospholipase Cγ1 controls surface expression of TRPC3 through an intermolecular PH domain. Nature 2005; 434:99-104. [PMID: 15744307 DOI: 10.1038/nature03340] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2004] [Accepted: 12/17/2004] [Indexed: 11/09/2022]
Abstract
Many ion channels are regulated by lipids, but prominent motifs for lipid binding have not been identified in most ion channels. Recently, we reported that phospholipase Cgamma1 (PLC-gamma1) binds to and regulates TRPC3 channels, components of agonist-induced Ca2+ entry into cells. This interaction requires a domain in PLC-gamma1 that includes a partial pleckstrin homology (PH) domain-a consensus lipid-binding and protein-binding sequence. We have developed a gestalt algorithm to detect hitherto 'invisible' PH and PH-like domains, and now report that the partial PH domain of PLC-gamma1 interacts with a complementary partial PH-like domain in TRPC3 to elicit lipid binding and cell-surface expression of TRPC3. Our findings imply a far greater abundance of PH domains than previously appreciated, and suggest that intermolecular PH-like domains represent a widespread signalling mode.
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Affiliation(s)
- Damian B van Rossum
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Spassova MA, Soboloff J, He LP, Hewavitharana T, Xu W, Venkatachalam K, van Rossum DB, Patterson RL, Gill DL. Calcium entry mediated by SOCs and TRP channels: variations and enigma. Biochim Biophys Acta 2005; 1742:9-20. [PMID: 15590052 DOI: 10.1016/j.bbamcr.2004.09.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2004] [Revised: 08/30/2004] [Accepted: 09/01/2004] [Indexed: 11/28/2022]
Abstract
Ca(2+) signals in response to receptors mediate and control countless cellular functions ranging from short-term responses such as secretion and contraction to longer-term regulation of growth, cell division and apoptosis. The spatial and temporal details of Ca(2+) signals have been resolved with great precision in many cells. Ca(2+) signals activated by phospholipase C-coupled receptors have two components: Ca(2+) release from endoplasmic reticulum (ER) stores mediated by inositol 1,4,5-trisphosphate (InsP(3)) receptors, and Ca(2+) entry from outside the cell. The latter remains largely a molecular and mechanistic mystery. The activation of "store-operated" Ca(2+) channels is believed to account for the entry of Ca(2+). However, debate now focuses on how much of a contribution emptying of stores plays to the activation of Ca(2+) entry in response to physiological activation of receptors. Here we discuss recent information and ideas on the exchange of signals between the plasma membrane (PM) and ER that results in activation of Ca(2+) entry channels following receptor stimulation and/or store emptying.
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Affiliation(s)
- Maria A Spassova
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
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Patterson RL, van Rossum DB, Kaplin AI, Barrow RK, Snyder SH. Inositol 1,4,5-trisphosphate receptor/GAPDH complex augments Ca2+ release via locally derived NADH. Proc Natl Acad Sci U S A 2005; 102:1357-9. [PMID: 15677321 PMCID: PMC547892 DOI: 10.1073/pnas.0409657102] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
NADH regulates the release of calcium from the endoplasmic reticulum by modulation of inositol 1,4,5-trisphosphate receptors (IP3R), accounting for the augmented calcium release of hypoxic cells. We report selective binding of IP3R to GAPDH, whose activity leads to the local generation of NADH to regulate intracellular calcium signaling. This interaction requires cysteines 992 and 995 of IP3R and C150 of GAPDH. Addition of native GAPDH and NAD+ to WT IP3R stimulates calcium release, whereas no stimulation occurs with C992S/995S IP3R that cannot bind GAPDH. Thus, the IP3R/GAPDH interaction likely enables cellular energy dynamics to impact calcium signaling.
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Affiliation(s)
- Randen L Patterson
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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Boehning D, van Rossum DB, Patterson RL, Snyder SH. A peptide inhibitor of cytochrome c/inositol 1,4,5-trisphosphate receptor binding blocks intrinsic and extrinsic cell death pathways. Proc Natl Acad Sci U S A 2005; 102:1466-71. [PMID: 15665074 PMCID: PMC547891 DOI: 10.1073/pnas.0409650102] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Apoptotic stimuli augment intracellular calcium concentration through inositol 1,4,5-trisphosphate receptors (IP3R) on endoplasmic reticulum calcium stores. We previously discovered an apoptotic cascade wherein cytochrome c binds to IP3R early in apoptosis, resulting in dysregulated calcium release. Here we show that cytochrome c binding to IP3R depends on a cluster of glutamic acid residues within the C terminus of the channel. A cell permeant peptide derived from this sequence displaces cytochrome c from IP3R and abrogates cell death induced by staurosporine treatment of HeLa cells and Fas ligand stimulation of Jurkat cells. Small-molecule inhibitors of cytochrome c/IP3R interactions may prove useful in treating disorders associated with inappropriate intrinsic and extrinsic apoptotic signaling.
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Affiliation(s)
- Darren Boehning
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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van Rossum DB, Patterson RL, Kiselyov K, Boehning D, Barrow RK, Gill DL, Snyder SH. Agonist-induced Ca2+ entry determined by inositol 1,4,5-trisphosphate recognition. Proc Natl Acad Sci U S A 2004; 101:2323-7. [PMID: 14983008 PMCID: PMC356949 DOI: 10.1073/pnas.0308565100] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been considered that Ca2+ release is the causal trigger for Ca2+ entry after receptor activation. In DT40 B cells devoid of inositol 1,4,5-trisphosphate receptors (IP3R), the lack of Ca2+ entry in response to receptor activation is attributed to the absence of Ca2+ release. We reveal in this article that IP3R recognition of IP3 determines agonist-induced Ca2+ entry (ACE), independent of its Ca2+ release activity. In DT40 IP3R(-/-) cells, endogenous ACE can be rescued with type 1 IP3R mutants (both a DeltaC-terminal truncation mutant and a D2550A pore mutant), which are defective in Ca2+ release channel activity. Thus, in response to B cell receptor activation, ACE is restored in an IP3R-dependent manner without Ca2+ store release. Conversely, ACE cannot be rescued with mutant IP3Rs lacking IP3 binding (both the Delta90-110 and R265Q IP3-binding site mutants). We conclude that an IP3-dependent conformational change in the IP3R, not endoplasmic reticulum Ca2+ pool release, triggers ACE.
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Affiliation(s)
- Damian B van Rossum
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Abstract
RACK1 is not a G protein but closely resembles the heterotrimeric Gbeta-subunit. RACK1 serves as a scaffold, linking protein kinase C to its substrates. We demonstrate that RACK1 physiologically binds inositol 1,4,5-trisphosphate receptors and regulates Ca2+ release by enhancing inositol 1,4,5-trisphosphate receptor binding affinity for inositol 1,4,5-trisphosphate. Overexpression of RACK1 or depletion of RACK1 by interference RNA markedly augments or diminishes Ca2+ release, respectively, without affecting Ca2+ entry. These findings establish RACK1 as a physiologic mediator of agonist-induced Ca2+ release.
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Affiliation(s)
- Randen L Patterson
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Abstract
We report here that PLC-gamma isoforms are required for agonist-induced Ca2+ entry (ACE). Overexpressed wild-type PLC-gamma1 or a lipase-inactive mutant PLC-gamma1 each augmented ACE in PC12 cells, while a deletion mutant lacking the region containing the SH3 domain of PLC-gamma1 was ineffective. RNA interference to deplete either PLC-gamma1 or PLC-gamma2 in PC12 and A7r5 cells inhibited ACE. In DT40 B lymphocytes expressing only PLC-gamma2, overexpressed muscarinic M5 receptors (M5R) activated ACE. Using DT40 PLC-gamma2 knockout cells, M5R stimulation of ER Ca2+ store release was unaffected, but ACE was abolished. Normal ACE was restored by transient expression of PLC-gamma2 or a lipase-inactive PLC-gamma2 mutant. The results indicate a lipase-independent role of PLC-gamma in the physiological agonist-induced activation of Ca2+ entry.
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Affiliation(s)
- Randen L Patterson
- Department of Neuroscience, Department of Pharmacology and Molecular Sciences, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Abstract
The impact of calcium signalling on so many areas of cell biology reflects the crucial role of calcium signals in the control of diverse cellular functions. Despite the precision with which spatial and temporal details of calcium signals have been resolved, a fundamental aspect of the generation of calcium signals -- the activation of 'store-operated channels' (SOCs) -- remains a molecular and mechanistic mystery. Here we review new insights into the exchange of signals between the endoplasmic reticulum (ER) and plasma membrane that result in activation of calcium entry channels mediating crucial long-term calcium signals.
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Affiliation(s)
- Kartik Venkatachalam
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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