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Rai A, Shrivastava R, Vang D, Ritt M, Sadler F, Bhaban S, Salapaka M, Sivaramakrishnan S. Multimodal regulation of myosin VI ensemble transport by cargo adaptor protein GIPC. J Biol Chem 2022; 298:101688. [PMID: 35143838 PMCID: PMC8908270 DOI: 10.1016/j.jbc.2022.101688] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 11/30/2022] Open
Abstract
A range of cargo adaptor proteins are known to recruit cytoskeletal motors to distinct subcellular compartments. However, the structural impact of cargo recruitment on motor function is poorly understood. Here, we dissect the multimodal regulation of myosin VI activity through the cargo adaptor GAIP-interacting protein, C terminus (GIPC), whose overexpression with this motor in cancer enhances cell migration. Using a range of biophysical techniques, including motility assays, FRET-based conformational sensors, optical trapping, and DNA origami-based cargo scaffolds to probe the individual and ensemble properties of GIPC-myosin VI motility, we report that the GIPC myosin-interacting region (MIR) releases an autoinhibitory interaction within myosin VI. We show that the resulting conformational changes in the myosin lever arm, including the proximal tail domain, increase the flexibility of the adaptor-motor linkage, and that increased flexibility correlates with faster actomyosin association and dissociation rates. Taken together, the GIPC MIR-myosin VI interaction stimulates a twofold to threefold increase in ensemble cargo speed. Furthermore, the GIPC MIR-myosin VI ensembles yield similar cargo run lengths as forced processive myosin VI dimers. We conclude that the emergent behavior from these individual aspects of myosin regulation is the fast, processive, and smooth cargo transport on cellular actin networks. Our study delineates the multimodal regulation of myosin VI by the cargo adaptor GIPC, while highlighting linkage flexibility as a novel biophysical mechanism for modulating cellular cargo motility.
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Affiliation(s)
- Ashim Rai
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Rachit Shrivastava
- Department of Electrical and Computer Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Duha Vang
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Fredrik Sadler
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Shreyas Bhaban
- Department of Electrical and Computer Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Murti Salapaka
- Department of Electrical and Computer Engineering, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA.
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2
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Ghashghaeinia M, Mrowietz U. Human erythrocytes, nuclear factor kappaB (NFκB) and hydrogen sulfide (H 2S) - from non-genomic to genomic research. Cell Cycle 2021; 20:2091-2101. [PMID: 34559024 PMCID: PMC8565816 DOI: 10.1080/15384101.2021.1972557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 12/13/2022] Open
Abstract
Enucleated mature human erythrocytes possess NFĸBs and their upstream kinases. There is a negative correlation between eryptosis (cell death of erythrocytes) and the amount of NFĸB subunits p50 and Rel A (p65). This finding is based on the fact that young erythrocytes have the highest levels of NFĸBs and the lowest eryptosis rate, while in old erythrocytes the opposite ratio prevails. Human erythrocytes (hRBCs) effectively control the homeostasis of the cell membrane permeable anti-inflammatory signal molecule hydrogen sulfide (H2S). They endogenously produce H2S via both non-enzymic (glutathione-dependent) and enzymic processes (mercaptopyruvate sulfur transferase-dependent). They uptake H2S from diverse tissues and very effectively degrade H2S via methemoglobin (Hb-Fe3+)-catalyzed oxidation. Interestingly, a reciprocal correlation exists between the intensity of inflammatory diseases and endogenous levels of H2S. H2S deficiency has been observed in patients with diabetes, psoriasis, obesity, and chronic kidney disease (CKD). Furthermore, endogenous H2S deficiency results in impaired renal erythropoietin (EPO) production and EPO-dependent erythropoiesis. In general we can say: dynamic reciprocal interaction between tumor suppressor and oncoproteins, orchestrated and sequential activation of pro-inflammatory NFĸB heterodimers (RelA-p50) and the anti-inflammatory NFĸB-p50 homodimers for optimal inflammation response, appropriate generation, subsequent degradation of H2S etc., are prerequisites for a functioning cell and organism. Diseases arise when the fragile balance between different signaling pathways that keep each other in check is permanently disturbed. This work deals with the intact anti-inflammatory hRBCs and their role as guarantors to maintain the redox status in the physiological range, a basis for general health and well-being.
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Affiliation(s)
- Mehrdad Ghashghaeinia
- Physiological Institute I, Department of Vegetative and Clinical Physiology, University of Tübingen, Tübingen, Germany
- Psoriasis-Center, Department of Dermatology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Ulrich Mrowietz
- Psoriasis-Center, Department of Dermatology, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
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3
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Lippert LG, Ma N, Ritt M, Jain A, Vaidehi N, Sivaramakrishnan S. Kinase inhibitors allosterically disrupt a regulatory interaction to enhance PKCα membrane translocation. J Biol Chem 2021; 296:100339. [PMID: 33508318 PMCID: PMC7949123 DOI: 10.1016/j.jbc.2021.100339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 10/28/2022] Open
Abstract
The eukaryotic kinase domain has multiple intrinsically disordered regions whose conformation dictates kinase activity. Small molecule kinase inhibitors (SMKIs) rely on disrupting the active conformations of these disordered regions to inactivate the kinase. While SMKIs are selected for their ability to cause this disruption, the allosteric effects of conformational changes in disordered regions is limited by a lack of dynamic information provided by traditional structural techniques. In this study, we integrated multiscale molecular dynamics simulations with FRET sensors to characterize a novel allosteric mechanism that is selectively triggered by SMKI binding to the protein kinase Cα domain. The indole maleimide inhibitors BimI and sotrastaurin were found to displace the Gly-rich loop (G-loop) that normally shields the ATP-binding site. Displacement of the G-loop interferes with a newly identified, structurally conserved binding pocket for the C1a domain on the N lobe of the kinase domain. This binding pocket, in conjunction with the N-terminal regulatory sequence, masks a diacylglycerol (DAG) binding site on the C1a domain. SMKI-mediated displacement of the G-loop released C1a and exposed the DAG binding site, enhancing protein kinase Cα translocation both to synthetic lipid bilayers and to live cell membranes in the presence of DAG. Inhibitor chemotype determined the extent of the observed allosteric effects on the kinase domain and correlated with the extent of membrane recruitment. Our findings demonstrate the allosteric effects of SMKIs beyond the confines of kinase catalytic conformation and provide an integrated computational-experimental paradigm to investigate parallel mechanisms in other kinases.
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Affiliation(s)
- Lisa G Lippert
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Abhinandan Jain
- The Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA.
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA.
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4
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Gupte TM, Ritt M, Sivaramakrishnan S. ER/K-link-Leveraging a native protein linker to probe dynamic cellular interactions. Methods Enzymol 2020; 647:173-208. [PMID: 33482988 PMCID: PMC8009693 DOI: 10.1016/bs.mie.2020.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ER/K α-helices are a subset of single alpha helical domains, which exhibit unusual stability as isolated protein secondary structures. They adopt an elongated structural conformation, while regulating the frequency of interactions between proteins or polypeptides fused to their ends. Here we review recent advances on the structure, stability and function of ER/K α-helices as linkers (ER/K linkers) in native proteins. We describe methodological considerations in the molecular cloning, protein expression and measurement of interaction strengths, using sensors incorporating ER/K linkers. We highlight biological insights obtained over the last decade by leveraging distinct biophysical features of ER/K-linked sensors. We conclude with the outlook for the use of ER/K linkers in the selective modulation of dynamic cellular interactions.
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Affiliation(s)
- Tejas M Gupte
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States.
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5
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Wasnik VH, Lipp P, Kruse K. Accuracy of position determination in Ca^{2+} signaling. Phys Rev E 2019; 100:022401. [PMID: 31574643 DOI: 10.1103/physreve.100.022401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Indexed: 02/02/2023]
Abstract
A living cell senses its environment and responds to external signals. In this paper, we study theoretically the precision at which cells can determine the position of a spatially localized transient extracellular signal. To this end, we focus on the case where the stimulus is converted into the release of a small molecule that acts as a second messenger, for example, Ca^{2+}, and activates kinases that change the activity of enzymes by phosphorylating them. We analyze the spatial distribution of phosphorylation events using stochastic simulations as well as a mean-field approach. Kinases that need to bind to the cell membrane for getting activated provide more accurate estimates than cytosolic kinases. Our results could explain why the rate of Ca^{2+} detachment from the membrane-binding conventional protein kinase Cα is larger than its phosphorylation rate.
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Affiliation(s)
- Vaibhav H Wasnik
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland.,Indian Institute of Technology Goa, Ponda 403401, India
| | - Peter Lipp
- Institute for Molecular Cell Biology, Research Centre for Molecular Imaging and Screening, Center for Molecular Signaling, Medical Faculty, Saarland University, Homburg/Saar, Germany
| | - Karsten Kruse
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland
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6
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Wasnik VH, Lipp P, Kruse K. Positional Information Readout in Ca^{2+} Signaling. PHYSICAL REVIEW LETTERS 2019; 123:058102. [PMID: 31491303 DOI: 10.1103/physrevlett.123.058102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/20/2018] [Indexed: 06/10/2023]
Abstract
Living cells respond to spatially confined signals. Intracellular signal transmission often involves the release of second messengers like Ca^{2+}. They eventually trigger a physiological response, for example, by activating kinases that in turn activate target proteins through phosphorylation. Here, we investigate theoretically how positional information can be accurately read out by protein phosphorylation in spite of rapid second messenger diffusion. We find that accuracy is increased by binding of kinases to the cell membrane prior to phosphorylation and by increasing the rate of Ca^{2+} loss from the cell interior. These findings could explain some salient features of the conventional protein kinase Cα.
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Affiliation(s)
- Vaibhav H Wasnik
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland
- Indian Institute of Technology Goa, Ponda 403401, India
| | - Peter Lipp
- Institute for Molecular Cell Biology, Research Centre for Molecular Imaging and Screening, Center for Molecular Signaling (PZMS), Medical Faculty, Saarland University, 66421 Homburg/Saar, Germany
| | - Karsten Kruse
- NCCR Chemical Biology, Departments of Biochemistry and Theoretical Physics, University of Geneva, 1211 Geneva, Switzerland
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Cole TR, Erickson SG, Morales KA, Sung M, Holzenburg A, Igumenova TI. Cd(II)- and Pb(II)-Induced Self-Assembly of Peripheral Membrane Domains from Protein Kinase C. Biochemistry 2019; 58:509-513. [PMID: 30584764 DOI: 10.1021/acs.biochem.8b01235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cd2+ and Pb2+ are xenobiotic heavy metal ions that use ionic mimicry to interfere with the cellular function of biomacromolecules. Using a combination of SAXS, electron microscopy, FRET, and solution NMR spectroscopy, we demonstrate that treatment with Cd2+ and Pb2+ causes self-assembly of protein kinase C regulatory domains that peripherally associate with membranes. The self-assembly process successfully competes with ionic mimicry and is mediated by conserved protein regions that are distinct from the canonical Ca2+-binding motifs of protein kinase C. The ability of protein oligomers to interact with anionic membranes is enhanced compared to the monomeric species. Our findings suggest that metal-ion-dependent peripheral membrane domains can be utilized for generating protein-metal-ion nanoclusters and serve as biotemplates for the design of sequestration agents.
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Affiliation(s)
- Taylor R Cole
- Department of Biochemistry and Biophysics , Texas A&M University , 300 Olsen Boulevard , College Station , Texas 77843 , United States
| | - Samuel G Erickson
- Department of Biochemistry and Biophysics , Texas A&M University , 300 Olsen Boulevard , College Station , Texas 77843 , United States
| | - Krystal A Morales
- Department of Biochemistry and Biophysics , Texas A&M University , 300 Olsen Boulevard , College Station , Texas 77843 , United States
| | - MinWoo Sung
- Department of Biology , Texas A&M University , College Station , Texas 77843 , United States
| | - Andreas Holzenburg
- School of Medicine , University of Texas Rio Grande Valley , Harlingen , Texas 78550 , United States
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics , Texas A&M University , 300 Olsen Boulevard , College Station , Texas 77843 , United States
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8
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Zhang X, Ye Q, Gong D, Lv Y, Cheng H, Huang C, Chen L, Zhao Z, Li L, Wei X, Zhang M, Xia X, Yu X, Zheng X, Wang S, Wang Z, Tang C. Apelin-13 inhibits lipoprotein lipase expression via the APJ/PKCα/miR-361-5p signaling pathway in THP-1 macrophage-derived foam cells. Acta Biochim Biophys Sin (Shanghai) 2017; 49:530-540. [PMID: 28444107 DOI: 10.1093/abbs/gmx038] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Indexed: 12/13/2022] Open
Abstract
Atherosclerotic lesions are characterized by the accumulation of abundant lipids and chronic inflammation. Previous researches have indicated that macrophage-derived lipoprotein lipase (LPL) promotes atherosclerosis progression by accelerating lipid accumulation and pro-inflammatory cytokine secretion. Although apelin-13 has been regarded as an atheroprotective factor, it remains unclear whether it can regulate the expression of LPL. The aim of this study was to explore the effects of apelin-13 on the expression of LPL and the underlying mechanism in THP-1 macrophage-derived foam cells. Apelin-13 significantly decreased cellular levels of total cholesterol, free cholesterol, and cholesterol ester at the concentrations of 10 and 100 nM. ELISA analysis confirmed that treatment with apelin-13 reduced pro-inflammatory cytokine secretion, such as interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). It was also found that apelin-13 inhibited the expression of LPL as revealed by western blot and real-time PCR analyses. Bioinformatics analyses and dual-luciferase reporter assay indicated that miR-361-5p directly downregulated the expression of LPL by targeting the 3'UTR of LPL. In addition, apelin-13 + miR-361-5p mimic significantly downregulated the expression of LPL in cells. Finally, we demonstrated that apelin-13 downregulated the expression of LPL through activating the activity of PKCα. Taken together, our results showed that apelin-13 downregulated the expression of LPL via activating the APJ/PKCα/miR-361-5p signaling pathway in THP-1 macrophage-derived foam cells, leading to inhibition of lipid accumulation and pro-inflammatory cytokine secretion. Therefore, our studies provide important new insight into the inhibition of lipid accumulation and pro-inflammatory cytokine secretion by apelin-13, and highlight apelin-13 as a promising therapeutic target in atherosclerosis.
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Affiliation(s)
- Xin Zhang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
- Department of Biochemistry and Molecular Biology, School of Pharmacy and Life Science University of South China, Hengyang 421001, China
| | - Qiong Ye
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of University of South China, Hengyang 421001, China
| | - Duo Gong
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Yuan Lv
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
- Department of Biochemistry and Molecular Biology, School of Pharmacy and Life Science University of South China, Hengyang 421001, China
| | - Haipeng Cheng
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Chong Huang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Lingyan Chen
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Zhenwang Zhao
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Liang Li
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xie Wei
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Min Zhang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xiaodan Xia
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xiaohua Yu
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
| | - Xilong Zheng
- Department of Biochemistry and Molecular Biology, Cumming School of Medicine, Libin Cardiovascular Institute of Alberta, University of Calgary, Health Sciences Center, Calgary, Alberta, CanadaT2N 4N1
| | - Shuzhi Wang
- Department of Biochemistry and Molecular Biology, School of Pharmacy and Life Science University of South China, Hengyang 421001, China
| | - Zongbao Wang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
- Department of Biochemistry and Molecular Biology, School of Pharmacy and Life Science University of South China, Hengyang 421001, China
| | - Chaoke Tang
- Institute of Cardiovascular Research, Key Laboratory for Atherosclerology of Hunan Province, Medical Research Center, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang 421001, China
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9
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Sommese RF, Ritt M, Swanson CJ, Sivaramakrishnan S. The Role of Regulatory Domains in Maintaining Autoinhibition in the Multidomain Kinase PKCα. J Biol Chem 2017; 292:2873-2880. [PMID: 28049730 DOI: 10.1074/jbc.m116.768457] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/30/2016] [Indexed: 11/06/2022] Open
Abstract
Resolving the conformational dynamics of large multidomain proteins has proven to be a significant challenge. Here we use a variety of techniques to dissect the roles of individual protein kinase Cα (PKCα) regulatory domains in maintaining catalytic autoinhibition. We find that whereas the pseudosubstrate domain is necessary for autoinhibition it is not sufficient. Instead, each regulatory domain (C1a, C1b, and C2) appears to strengthen the pseudosubstrate-catalytic domain interaction in a nucleotide-dependent manner. The pseudosubstrate and C1a domains, however, are minimally essential for maintaining the inactivated state. Furthermore, disrupting known interactions between the C1a and other regulatory domains releases the autoinhibited interaction and increases basal activity. Modulating this interaction between the catalytic and regulatory domains reveals a direct correlation between autoinhibition and membrane translocation following PKC activation.
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Affiliation(s)
- Ruth F Sommese
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Michael Ritt
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Carter J Swanson
- the Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Sivaraj Sivaramakrishnan
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
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