1
|
Camara A, Chugh H, George A, Dolidze L, Ryu K, Holly KJ, Flaherty DP, Mattoo S. Discovery and validation of a novel inhibitor of HYPE-mediated AMPylation. Cell Stress Chaperones 2024; 29:404-424. [PMID: 38599565 PMCID: PMC11053294 DOI: 10.1016/j.cstres.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024] Open
Abstract
Adenosyl monophosphate (AMP)ylation (the covalent transfer of an AMP from Adenosine Triphosphate (ATP) onto a target protein) is catalyzed by the human enzyme Huntingtin Yeast Interacting Partner E (HYPE)/FicD to regulate its substrate, the heat shock chaperone binding immunoglobulin protein (BiP). HYPE-mediated AMPylation of BiP is critical for maintaining proteostasis in the endoplasmic reticulum and mounting a unfolded protein response in times of proteostatic imbalance. Thus, manipulating HYPE's enzymatic activity is a key therapeutic strategy toward the treatment of various protein misfolding diseases, including neuropathy and early-onset diabetes associated with two recently identified clinical mutations of HYPE. Herein, we present an optimized, fluorescence polarization-based, high-throughput screening (HTS) assay to discover activators and inhibitors of HYPE-mediated AMPylation. After challenging our HTS assay with over 30,000 compounds, we discovered a novel AMPylase inhibitor, I2.10. We also determined a low micromolar IC50 for I2.10 and employed biorthogonal counter-screens to validate its efficacy against HYPE's AMPylation of BiP. Further, we report low cytotoxicity of I2.10 on human cell lines. We thus established an optimized, high-quality HTS assay amenable to tracking HYPE's enzymatic activity at scale, and provided the first novel small-molecule inhibitor capable of perturbing HYPE-directed AMPylation of BiP in vitro. Our HTS assay and I2.10 compound serve as a platform for further development of HYPE-specific small-molecule therapeutics.
Collapse
Affiliation(s)
- Ali Camara
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Heerak Chugh
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Drug Discovery and Development Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Alyssa George
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Lukas Dolidze
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Kevin Ryu
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Katrina J Holly
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, USA
| | - Daniel P Flaherty
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN, USA
| | - Seema Mattoo
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, USA; Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA.
| |
Collapse
|
2
|
Petrova ON, Lamarre I, Fasani F, Grillon C, Negrerie M. Soluble Guanylate Cyclase Inhibitors Discovered among Natural Compounds. JOURNAL OF NATURAL PRODUCTS 2020; 83:3642-3651. [PMID: 33290062 DOI: 10.1021/acs.jnatprod.0c00854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Soluble guanylate cyclase (sGC) is the human receptor of nitric oxide (NO) in numerous kinds of cells and produces the second messenger 3',5'-cyclic guanosine monophosphate (cGMP) upon NO binding to its heme. sGC is involved in many cell signaling pathways both under healthy conditions and under pathological conditions, such as angiogenesis associated with tumor growth. Addressing the selective inhibition of the NO/cGMP pathway is a strategy worthwhile to be investigated for slowing down tumoral angiogenesis or for curing vasoplegia. However, sGC inhibitors are lacking investigation. We have explored a chemical library of various natural compounds and have discovered inhibitors of sGC. The selected compounds were evaluated for their inhibition of purified sGC in vitro and sGC in endothelial cells. Six natural compounds, from various organisms, have IC50 in the range 0.2-1.5 μM for inhibiting the NO-activated synthesis of cGMP by sGC, and selected compounds exhibit a quantified antiangiogenic activity using an endothelial cell line. These sGC inhibitors can be used directly as tools to investigate angiogenesis and cell signaling or as templates for drug design.
Collapse
Affiliation(s)
- Olga N Petrova
- Laboratoire d'Optique et Biosciences, INSERM U1182, Ecole Polytechnique, Palaiseau, France
| | - Isabelle Lamarre
- Laboratoire d'Optique et Biosciences, INSERM U1182, Ecole Polytechnique, Palaiseau, France
| | - Fabienne Fasani
- Centre de Biophysique Moléculaire, UPR4301 CNRS, Orléans, France
| | | | - Michel Negrerie
- Laboratoire d'Optique et Biosciences, INSERM U1182, Ecole Polytechnique, Palaiseau, France
| |
Collapse
|
3
|
Camara A, George A, Hebner E, Mahmood A, Paluru J, Mattoo S. A Fluorescence Polarization-Based High-Throughput Screen to Identify the First Small-Molecule Modulators of the Human Adenylyltransferase HYPE/FICD. Int J Mol Sci 2020; 21:E7128. [PMID: 32992526 PMCID: PMC7582957 DOI: 10.3390/ijms21197128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/24/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
The covalent transfer of the AMP portion of ATP onto a target protein-termed adenylylation or AMPylation-by the human Fic protein HYPE/FICD has recently garnered attention as a key regulatory mechanism in endoplasmic reticulum homeostasis, neurodegeneration, and neurogenesis. As a central player in such critical cellular events, high-throughput screening (HTS) efforts targeting HYPE-mediated AMPylation warrant investigation. Herein, we present a dual HTS assay for the simultaneous identification of small-molecule activators and inhibitors of HYPE AMPylation. Employing the fluorescence polarization of an ATP analog fluorophore-Fl-ATP-we developed and optimized an efficient, robust assay that monitors HYPE autoAMPylation and is amenable to automated, high-throughput processing of diverse chemical libraries. Challenging our pilot screen with compounds from the LOPAC, Spectrum, MEGx, and NATx libraries yielded 0.3% and 1% hit rates for HYPE activators and inhibitors, respectively. Further, these hits were assessed for dose-dependency and validated via orthogonal biochemical AMPylation assays. We thus present a high-quality HTS assay suitable for tracking HYPE's enzymatic activity, and the resultant first small-molecule manipulators of HYPE-promoted autoAMPylation.
Collapse
Affiliation(s)
- Ali Camara
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (A.C.); (A.G.); (E.H.); (A.M.)
| | - Alyssa George
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (A.C.); (A.G.); (E.H.); (A.M.)
| | - Evan Hebner
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (A.C.); (A.G.); (E.H.); (A.M.)
| | - Anika Mahmood
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (A.C.); (A.G.); (E.H.); (A.M.)
| | - Jashun Paluru
- William Henry Harrison High School, West Lafayette, IN 47906, USA;
| | - Seema Mattoo
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA; (A.C.); (A.G.); (E.H.); (A.M.)
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| |
Collapse
|
4
|
Calcium signaling mediated by aminergic GPCRs is impaired by the PI3K inhibitor LY294002 and its analog LY303511 in a PI3K-independent manner. Eur J Pharmacol 2020; 880:173182. [PMID: 32416185 DOI: 10.1016/j.ejphar.2020.173182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 04/17/2020] [Accepted: 05/08/2020] [Indexed: 12/23/2022]
Abstract
The phosphoinositide 3-kinase (PI3K) inhibitor LY294002 (LY294) and its much less active analog LY303511 (LY303) constitute the paired probe that is commonly used to demonstrate the involvement of PI3K in intracellular signaling. We studied effects of LY294 and LY303 on Ca2+ signaling initiated by certain GPCR agonists in cells of several lines, including CHO cells expressing the recombinant serotonin receptor 5-HT2C and mesenchymal stromal cells derived from the human adipose tissue (AD-MSCs) and umbilical cord (UD-MSCs). The LY294/LY303 pair exerted apparently specific effects on responsiveness of AD-MSCs to ATP, suggesting the involvement of PI3K in ATP transduction. Surprisingly, LY303 inhibited Ca2+ transients elicited by histamine in the same cells, while LY294 was ineffective. This observation and other findings implicated a PI3K-unrelated mechanism in mediating effects of the LY compound on AD-MSC responsiveness to histamine. With LY303 in the bath, the dose dependence of histamine responses was shifted positively at the invariable number of responsive cells, as would be the case with a competitive antagonist of histamine receptors. Moreover, LY303 and LY294 inhibited Ca2+ transients elicited by acetylcholine and serotonin in UD-MSCs and CHO/5-HT2C cells, respectively. Our overall results argued for the possibility that LY294 and LY303 could directly affect activity of aminergic GPCRs. Thus, LY303511 and LY294002 should be used cautiously in studies of PI3K as a factor of GPCR signaling.
Collapse
|
5
|
Szabo M, Dulka K, Gulya K. Calmodulin inhibition regulates morphological and functional changes related to the actin cytoskeleton in pure microglial cells. Brain Res Bull 2015; 120:41-57. [PMID: 26551061 DOI: 10.1016/j.brainresbull.2015.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/26/2015] [Accepted: 11/03/2015] [Indexed: 01/24/2023]
Abstract
The roles of calmodulin (CaM), a multifunctional intracellular calcium receptor protein, as concerns selected morphological and functional characteristics of pure microglial cells derived from mixed primary cultures from embryonal forebrains of rats, were investigated through use of the CaM antagonists calmidazolium (CALMID) and trifluoperazine (TFP). The intracellular localization of the CaM protein relative to phalloidin, a bicyclic heptapeptide that binds only to filamentous actin, and the ionized calcium-binding adaptor molecule 1 (Iba1), a microglia-specific actin-binding protein, was determined by immunocytochemistry, with quantitative analysis by immunoblotting. In unchallenged and untreated (control) microglia, high concentrations of CaM protein were found mainly perinuclearly in ameboid microglia, while the cell cortex had a smaller CaM content that diminished progressively deeper into the branches in the ramified microglia. The amounts and intracellular distributions of both Iba1 and CaM proteins were altered after lipopolysaccharide (LPS) challenge in activated microglia. CALMID and TFP exerted different, sometimes opposing, effects on many morphological, cytoskeletal and functional characteristics of the microglial cells. They affected the CaM and Iba1 protein expressions and their intracellular localizations differently, inhibited cell proliferation, viability and fluid-phase phagocytosis to different degrees both in unchallenged and in LPS-treated (immunologically challenged) cells, and differentially affected the reorganization of the actin cytoskeleton in the microglial cell cortex, influencing lamellipodia, filopodia and podosome formation. In summary, these CaM antagonists altered different aspects of filamentous actin-based cell morphology and related functions with variable efficacy, which could be important in deciphering the roles of CaM in regulating microglial functions in health and disease.
Collapse
Affiliation(s)
- Melinda Szabo
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Karolina Dulka
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Karoly Gulya
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
| |
Collapse
|
6
|
Effects of 39 Compounds on Calmodulin-Regulated Adenylyl Cyclases AC1 and Bacillus anthracis Edema Factor. PLoS One 2015; 10:e0124017. [PMID: 25946093 PMCID: PMC4422518 DOI: 10.1371/journal.pone.0124017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 03/09/2015] [Indexed: 12/29/2022] Open
Abstract
Adenylyl cyclases (ACs) catalyze the conversion of ATP into the second messenger cAMP. Membranous AC1 (AC1) is involved in processes of memory and learning and in muscle pain. The AC toxin edema factor (EF) of Bacillus anthracis is involved in the development of anthrax. Both ACs are stimulated by the eukaryotic Ca2+-sensor calmodulin (CaM). The CaM-AC interaction could constitute a potential target to enhance or impair the AC activity of AC1 and EF to intervene in above (patho)physiological mechanisms. Thus, we analyzed the impact of 39 compounds including typical CaM-inhibitors, an anticonvulsant, an anticholinergic, antidepressants, antipsychotics and Ca2+-antagonists on CaM-stimulated catalytic activity of AC1 and EF. Compounds were tested at 10 μM, i.e., a concentration that can be reached therapeutically for certain antidepressants and antipsychotics. Calmidazolium chloride decreased CaM-stimulated AC1 activity moderately by about 30%. In contrast, CaM-stimulated EF activity was abrogated by calmidazolium chloride and additionally decreased by chlorpromazine, felodipine, penfluridol and trifluoperazine by about 20–40%. The activity of both ACs was decreased by calmidazolium chloride in the presence and absence of CaM. Thus, CaM-stimulated AC1 activity is more insensitive to inhibition by small molecules than CaM-stimulated EF activity. Inhibition of AC1 and EF by calmidazolium chloride is largely mediated via a CaM-independent allosteric mechanism.
Collapse
|
7
|
Rogers NM, Seeger F, Garcin ED, Roberts DD, Isenberg JS. Regulation of soluble guanylate cyclase by matricellular thrombospondins: implications for blood flow. Front Physiol 2014; 5:134. [PMID: 24772092 PMCID: PMC3983488 DOI: 10.3389/fphys.2014.00134] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/18/2014] [Indexed: 01/16/2023] Open
Abstract
Nitric oxide (NO) maintains cardiovascular health by activating soluble guanylate cyclase (sGC) to increase cellular cGMP levels. Cardiovascular disease is characterized by decreased NO-sGC-cGMP signaling. Pharmacological activators and stimulators of sGC are being actively pursued as therapies for acute heart failure and pulmonary hypertension. Here we review molecular mechanisms that modulate sGC activity while emphasizing a novel biochemical pathway in which binding of the matricellular protein thrombospondin-1 (TSP1) to the cell surface receptor CD47 causes inhibition of sGC. We discuss the therapeutic implications of this pathway for blood flow, tissue perfusion, and cell survival under physiologic and disease conditions.
Collapse
Affiliation(s)
- Natasha M Rogers
- Department of Medicine, Vascular Medicine Institute, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Franziska Seeger
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County Baltimore, MD, USA
| | - Elsa D Garcin
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County Baltimore, MD, USA
| | - David D Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, NIH Bethesda, MD, USA
| | - Jeffrey S Isenberg
- Department of Medicine, Vascular Medicine Institute, University of Pittsburgh School of Medicine Pittsburgh, PA, USA ; Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| |
Collapse
|
8
|
Towards selective inhibitors of adenylyl cyclase toxin from Bordetella pertussis. Trends Microbiol 2012; 20:343-51. [PMID: 22578665 DOI: 10.1016/j.tim.2012.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Revised: 03/27/2012] [Accepted: 04/04/2012] [Indexed: 12/19/2022]
Abstract
Whooping cough is a very important medical problem that requires novel approaches for treatment. The disease is caused by Bordetella pertussis, with the calmodulin (CaM)-activated adenylyl cyclase (AC) toxin (also known as CyaA) being a major virulence factor. Hence, CyaA inhibitors could constitute novel therapeutics, but it has been difficult to develop potent drugs with high selectivity over mammalian membranous ACs (mACs). Recent studies have shown that bis-anthraniloyl-substituted nucleoside 5'-triphosphates are potent and selective CyaA inhibitors. In addition, the interaction of CyaA with CaM is very different from the interaction of membranous mAC1 with CaM. Accordingly, compounds that interfere with the CyaA-CaM interaction may constitute a novel class of drugs against whooping cough.
Collapse
|
9
|
Schuler D, Lübker C, Lushington GH, Tang WJ, Shen Y, Richter M, Seifert R. Interactions of Bordetella pertussis adenylyl cyclase toxin CyaA with calmodulin mutants and calmodulin antagonists: comparison with membranous adenylyl cyclase I. Biochem Pharmacol 2012; 83:839-848. [PMID: 22265637 DOI: 10.1016/j.bcp.2012.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/03/2012] [Accepted: 01/04/2012] [Indexed: 01/12/2023]
Abstract
The adenylyl cyclase (AC) toxin CyaA from Bordetella pertussis constitutes an important virulence factor for the pathogenesis of whooping cough. CyaA is activated by calmodulin (CaM) and compromises host defense by excessive cAMP production. Hence, pharmacological modulation of the CyaA/CaM interaction could constitute a promising approach to treat whooping cough, provided that interactions of endogenous effector proteins with CaM are not affected. As a first step toward this ambitious goal we examined the interactions of CyaA with wild-type CaM and four CaM mutants in which most methionine residues were replaced by leucine residues and studied the effects of the CaM antagonists calmidazolium, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7). CyaA/CaM interaction was monitored by CaM-dependent fluorescence resonance energy transfer (FRET) between tryptophan residues in CyaA and 2'-(N-methylanthraniloyl)-3'-deoxy-adenosine 5'-triphosphate and catalytic activity. Comparison of the concentration/response curves of CaM and CaM mutants for FRET and catalysis revealed differences, suggesting a two-step activation mechanism of CyaA by CaM. Even in the absence of CaM, calmidazolium inhibited catalysis, and it did so according to a biphasic function. Trifluoperazine and W-7 did not inhibit FRET or catalysis. In contrast to CyaA, some CaM mutants were more efficacious than CaM at activating membranous AC isoform 1. The slope of CyaA activation by CaM was much steeper than of AC1 activation. Collectively, the two-step activation mechanism of CyaA by CaM offers opportunities for pharmacological intervention. The failure of classic CaM inhibitors to interfere with CyaA/CaM interactions and the different interactions of CaM mutants with CyaA and AC1 point to unique CyaA/CaM interactions.
Collapse
Affiliation(s)
- Dominik Schuler
- Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Carolin Lübker
- Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| | - Gerald H Lushington
- Molecular Graphics and Modeling Laboratory, The University of Kansas, KS 66045, USA
| | - Wei-Jen Tang
- Ben May Department of Cancer Research, The University of Chicago, Chicago, IL 60637, USA
| | - Yuequan Shen
- College of Life Sciences, Nankai University, 300071 Tianjin, People's Republic of China
| | - Mark Richter
- Department of Molecular Biosciences, The University of Kansas, Lawrence, KS 66045, USA
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany
| |
Collapse
|
10
|
Ramanathan S, Mazzalupo S, Boitano S, Montfort WR. Thrombospondin-1 and angiotensin II inhibit soluble guanylyl cyclase through an increase in intracellular calcium concentration. Biochemistry 2011; 50:7787-99. [PMID: 21823650 DOI: 10.1021/bi201060c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nitric oxide (NO) regulates cardiovascular hemostasis by binding to soluble guanylyl cyclase (sGC), leading to cGMP production, reduced cytosolic calcium concentration ([Ca(2+)](i)), and vasorelaxation. Thrombospondin-1 (TSP-1), a secreted matricellular protein, was recently discovered to inhibit NO signaling and sGC activity. Inhibition of sGC requires binding to cell-surface receptor CD47. Here, we show that a TSP-1 C-terminal fragment (E3CaG1) readily inhibits sGC in Jurkat T cells and that inhibition requires an increase in [Ca(2+)](i). Using flow cytometry, we show that E3CaG1 binds directly to CD47 on the surface of Jurkat T cells. Using digital imaging microscopy on live cells, we further show that E3CaG1 binding results in a substantial increase in [Ca(2+)](i), up to 300 nM. Addition of angiotensin II, a potent vasoconstrictor known to increase [Ca(2+)](i), also strongly inhibits sGC activity. sGC isolated from calcium-treated cells or from cell-free lysates supplemented with Ca(2+) remains inhibited, while addition of kinase inhibitor staurosporine prevents inhibition, indicating inhibition is likely due to phosphorylation. Inhibition is through an increase in K(m) for GTP, which rises to 834 μM for the NO-stimulated protein, a 13-fold increase over the uninhibited protein. Compounds YC-1 and BAY 41-2272, allosteric stimulators of sGC that are of interest for treating hypertension, overcome E3CaG1-mediated inhibition of NO-ligated sGC. Taken together, these data suggest that sGC not only lowers [Ca(2+)](i) in response to NO, inducing vasodilation, but also is inhibited by high [Ca(2+)](i), providing a fine balance between signals for vasodilation and vasoconstriction.
Collapse
Affiliation(s)
- Saumya Ramanathan
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, United States
| | | | | | | |
Collapse
|