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Iyer DN, Faruq O, Zhang L, Rastgoo N, Liu A, Chang H. Pathophysiological roles of myristoylated alanine-rich C-kinase substrate (MARCKS) in hematological malignancies. Biomark Res 2021; 9:34. [PMID: 33958003 PMCID: PMC8101130 DOI: 10.1186/s40364-021-00286-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/16/2021] [Indexed: 12/17/2022] Open
Abstract
The myristoylated alanine-rich C-kinase substrate (MARCKS) protein has been at the crossroads of multiple signaling pathways that govern several critical operations in normal and malignant cellular physiology. Functioning as a target of protein kinase C, MARCKS shuttles between the phosphorylated cytosolic form and the unphosphorylated plasma membrane-bound states whilst regulating several molecular partners including, but not limited to calmodulin, actin, phosphatidylinositol-4,5-bisphosphate, and phosphoinositide-3-kinase. As a result of these interactions, MARCKS directly or indirectly modulates a host of cellular functions, primarily including cytoskeletal reorganization, membrane trafficking, cell secretion, inflammatory response, cell migration, and mitosis. Recent evidence indicates that dysregulated expression of MARCKS is associated with the development and progression of hematological cancers. While it is understood that MARCKS impacts the overall carcinogenesis as well as plays a part in determining the disease outcome in blood cancers, we are still at an early stage of interpreting the pathophysiological roles of MARCKS in neoplastic disease. The situation is further complicated by contradictory reports regarding the role of phosphorylated versus an unphosphorylated form of MARCKS as an oncogene versus tumor suppressor in blood cancers. In this review, we will investigate the current body of knowledge and evolving concepts of the physical properties, molecular network, functional attributes, and the likely pathogenic roles of MARCKS in hematological malignancies. Key emphasis will also be laid upon understanding the novel mechanisms by which MARCKS determines the overall disease prognosis by playing a vital role in the induction of therapeutic resistance. Additionally, we will highlight the importance of MARCKS as a valuable therapeutic target in blood cancers and will discuss the potential of existing strategies available to tackle MARCKS-driven blood cancers.
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Affiliation(s)
- Deepak Narayanan Iyer
- Laboratory medicine program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada
| | - Omar Faruq
- Laboratory medicine program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada
| | - Lun Zhang
- Laboratory medicine program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada
| | - Nasrin Rastgoo
- Laboratory medicine program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada
| | - Aijun Liu
- Department of Hematology, Beijing Chaoyang Hospital, Capital University, Beijing, China.
| | - Hong Chang
- Laboratory medicine program, Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada.
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Wu C, Ba Q, Lu D, Li W, Salovska B, Hou P, Mueller T, Rosenberger G, Gao E, Di Y, Zhou H, Fornasiero EF, Liu Y. Global and Site-Specific Effect of Phosphorylation on Protein Turnover. Dev Cell 2020; 56:111-124.e6. [PMID: 33238149 DOI: 10.1016/j.devcel.2020.10.025] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 10/05/2020] [Accepted: 10/30/2020] [Indexed: 02/02/2023]
Abstract
To date, the effects of specific modification types and sites on protein lifetime have not been systematically illustrated. Here, we describe a proteomic method, DeltaSILAC, to quantitatively assess the impact of site-specific phosphorylation on the turnover of thousands of proteins in live cells. Based on the accurate and reproducible mass spectrometry-based method, a pulse labeling approach using stable isotope-labeled amino acids in cells (pSILAC), phosphoproteomics, and a unique peptide-level matching strategy, our DeltaSILAC profiling revealed a global, unexpected delaying effect of many phosphosites on protein turnover. We further found that phosphorylated sites accelerating protein turnover are functionally selected for cell fitness, enriched in Cyclin-dependent kinase substrates, and evolutionarily conserved, whereas the glutamic acids surrounding phosphosites significantly delay protein turnover. Our method represents a generalizable approach and provides a rich resource for prioritizing the effects of phosphorylation sites on protein lifetime in the context of cell signaling and disease biology.
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Affiliation(s)
- Chongde Wu
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Qian Ba
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Dayun Lu
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Wenxue Li
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Barbora Salovska
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Pingfu Hou
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Torsten Mueller
- German Cancer Research Center, DKFZ, 69120 Heidelberg, Germany
| | | | - Erli Gao
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Yi Di
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA
| | - Hu Zhou
- Department of Analytical Chemistry and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Eugenio F Fornasiero
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Yansheng Liu
- Yale Cancer Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Ye D, Wang X, Wei C, He M, Wang H, Wang Y, Zhu Z, Sun Y. Marcksb plays a key role in the secretory pathway of zebrafish Bmp2b. PLoS Genet 2019; 15:e1008306. [PMID: 31545789 PMCID: PMC6776368 DOI: 10.1371/journal.pgen.1008306] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 10/03/2019] [Accepted: 07/11/2019] [Indexed: 12/24/2022] Open
Abstract
During vertebrate early embryogenesis, the ventral development is directed by the ventral-to-dorsal activity gradient of the bone morphogenetic protein (BMP) signaling. As secreted ligands, the extracellular traffic of BMP has been extensively studied. However, it remains poorly understood that how BMP ligands are secreted from BMP-producing cells. In this work, we show the dominant role of Marcksb controlling the secretory process of Bmp2b via interaction with Hsp70 in vivo. We firstly carefully characterized the role of Marcksb in promoting BMP signaling during dorsoventral axis formation through knockdown approach. We then showed that Marcksb cell autonomously regulates the trafficking of Bmp2b from producing cell to the extracellular space and both the total and the extracellular Bmp2b was decreased in Marcksb-deficient embryos. However, neither the zygotic mutant of marcksb (Zmarcksb) nor the maternal zygotic mutant of marcksb (MZmarcksb) showed any defects of dorsalization. In contrast, the MZmarcksb embryos even showed increased BMP signaling activity as measured by expression of BMP targets, phosphorylated Smad1/5/9 levels and imaging of Bmp2b, suggesting that a phenomenon of “genetic over-compensation” arose. Finally, we revealed that the over-compensation effects of BMP signaling in MZmarcksb was achieved through a sequential up-regulation of MARCKS-family members Marcksa, Marcksl1a and Marcksl1b, and MARCKS-interacting protein Hsp70.3. We concluded that the Marcksb modulates BMP signaling through regulating the secretory pathway of Bmp2b. Bone morphogenetic proteins (BMPs) are extracellular proteins which belong to the transforming growth factor-β (TGF-β) superfamily. BMP signaling is essential for embryonic development, organogenesis, and tissue regeneration and homeostasis, and tightly linked to various diseases and tumorigenesis. However, as secreted proteins, how BMPs are transported and secreted from BMP-producing cells remains poorly understood. In this study, we showed that Marcksb interacts with a molecular chaperon–Hsp70.3 to mediate the secretory pathway of BMP ligands during early development of zebrafish. Moreover, we discovered a novel phenomenon of “genetic over-compensation” in the genetic knock-out mutants of marcksb. To our knowledge, this is the first report that reveals the molecules and their related trafficking system mediating the secretion of BMPs. Considering the wide distribution of BMP and MARCKS within the human body, our work may shed light on the studies of BMPs secretion in organogenesis and adult tissue homeostasis. The finding of MARCKS in controlling BMP secretion may provide potential therapeutic targets for modulating the activity of BMP signaling and thus will be of interest to clinical research.
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Affiliation(s)
- Ding Ye
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Xiaosi Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Changyong Wei
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Mudan He
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Houpeng Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Yanwu Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
| | - Zuoyan Zhu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
| | - Yonghua Sun
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Wuhan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Klug J, Torresan MF, Lurgo F, Borioli G, Lacconi GI. A spectroscopic sensing platform for MARCKS protein monolayers. J Colloid Interface Sci 2017; 508:532-541. [PMID: 28866462 DOI: 10.1016/j.jcis.2017.08.081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/23/2017] [Accepted: 08/24/2017] [Indexed: 11/16/2022]
Abstract
We developed a highly sensitive silicon platform, suitable to assess the molecular organization of protein samples. Prototype platforms were obtained using different electrochemical protocols for the electrodeposition of Ag-nanoparticles onto the hydrogenated silicon surface. A platform with high Surface Enhanced Raman Scattering efficiency was selected based on the surface coverage and the number density of particles size distribution. The performance of the platform was determined by studying the interaction of Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) protein with the substrate according to its molecular organization. The chemical and structural characteristics of MARCKS molecules were examined under two configurations: i) a disordered distribution given by a MARCKS solution drop deposited onto the platform and, ii) a compact monolayer transferred to the platform by the Langmuir-Blodgett method. Raman spectra show vibrational bands of Phenylalanine and Lysine residues specific for the protein effector domain, and evidence the presence of alpha helix structure in both configurations. Moreover, we distinguished the supramolecular order between the compact monolayer and random molecular distribution. The platforms containing Ag-nanoparticles are suitable for studies of protein structure and interactions, advancing a methodological strategy for our long term goal, which is to explore the interaction of proteins with model membranes.
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Affiliation(s)
- Joaquín Klug
- CONICET and Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras 1300, CP5500 Mendoza, Argentina
| | - María Fernanda Torresan
- INFIQC-CONICET, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre-Medina Allende, Ciudad Universitaria, RA-5000 Córdoba, Argentina
| | - Florencia Lurgo
- INFIQC-CONICET, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre-Medina Allende, Ciudad Universitaria, RA-5000 Córdoba, Argentina
| | - Graciela Borioli
- CIQUIBIC-CONICET, Dpto. de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre-Medina Allende, Ciudad Universitaria, RA-5000 Córdoba, Argentina.
| | - Gabriela I Lacconi
- INFIQC-CONICET, Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de La Torre-Medina Allende, Ciudad Universitaria, RA-5000 Córdoba, Argentina.
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Involvement of inhibition of RhoA/Rho kinase signaling in simvastatin-induced amelioration of neuropathic pain. Neuroscience 2016; 333:204-13. [PMID: 27457035 DOI: 10.1016/j.neuroscience.2016.07.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 07/14/2016] [Accepted: 07/18/2016] [Indexed: 12/19/2022]
Abstract
Small molecular G-protein plays a key role in several diseases. This study was designed to reveal the role of RhoA signaling in the pathophysiology of neuropathic pain in mice. Partial sciatic nerve injury caused thermal hyperalgesia, mechanical allodynia, and increased plasma membrane translocation of RhoA in the lumber spinal cord. GFAP-immunoreactivity (ir), Iba-1-ir, and Rho kinase 2 (ROCK2-ir) was also increased in the ipsilateral spinal dorsal horn of nerve-ligated mice. Moreover, partial nerve ligation increased the expression of phosphorylated myristoylated alanine-rich protein kinase C substrate (MARCKS)-ir in the ipsilateral spinal dorsal horn. Daily intrathecal administration of simvastatin, beginning 3days before nerve injury, completely blocked all these changes in nerve-ligated mice. Pharmacological inhibition of ROCK also attenuated the increased expression of GFAP-ir and phosphorylated MARCKS-ir. Together, it is suggested that astrogliosis initiated by the activation of RhoA/ROCK signaling results in MARCKS phosphorylation in nerve terminals, which leads to hyperalgesia in neuropathic pain. Furthermore, simvastatin exerts antihyperalgesic and antiallodynic effects through the inhibition of spinal RhoA activation.
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6
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Brudvig JJ, Weimer JM. X MARCKS the spot: myristoylated alanine-rich C kinase substrate in neuronal function and disease. Front Cell Neurosci 2015; 9:407. [PMID: 26528135 PMCID: PMC4602126 DOI: 10.3389/fncel.2015.00407] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 09/25/2015] [Indexed: 11/18/2022] Open
Abstract
Intracellular protein-protein interactions are dynamic events requiring tightly regulated spatial and temporal checkpoints. But how are these spatial and temporal cues integrated to produce highly specific molecular response patterns? A helpful analogy to this process is that of a cellular map, one based on the fleeting localization and activity of various coordinating proteins that direct a wide array of interactions between key molecules. One such protein, myristoylated alanine-rich C-kinase substrate (MARCKS) has recently emerged as an important component of this cellular map, governing a wide variety of protein interactions in every cell type within the brain. In addition to its well-documented interactions with the actin cytoskeleton, MARCKS has been found to interact with a number of other proteins involved in processes ranging from intracellular signaling to process outgrowth. Here, we will explore these diverse interactions and their role in an array of brain-specific functions that have important implications for many neurological conditions.
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Affiliation(s)
- Jon J Brudvig
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Basic Biomedical Sciences, University of South Dakota Vermillion, SD, USA
| | - Jill M Weimer
- Children's Health Research Center, Sanford Research Sioux Falls, SD, USA ; Department of Pediatrics, Sanford School of Medicine, University of South Dakota Vermillion, SD, USA
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Tinoco LW, Fraga JL, Anobom CD, Zolessi FR, Obal G, Toledo A, Pritsch O, Arruti C. Structural characterization of a neuroblast-specific phosphorylated region of MARCKS. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:837-49. [PMID: 24590112 DOI: 10.1016/j.bbapap.2014.02.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 02/07/2014] [Accepted: 02/20/2014] [Indexed: 11/19/2022]
Abstract
MARCKS (Myristoylated Alanine-Rich C Kinase substrate) is a natively unfolded protein that interacts with actin, Ca(2+)-Calmodulin, and some plasma membrane lipids. Such interactions occur at a highly conserved region that is specifically phosphorylated by PKC: the Effector Domain. There are two other conserved domains, MH1 (including a myristoylation site) and MH2, also located in the amino terminal region and whose structure and putative protein binding capabilities are currently unknown. MH2 sequence contains a serine that we described as being phosphorylated only in differentiating neurons (S25 in chick). Here, Circular Dichroism (CD) and Nuclear Magnetic Resonance (NMR) spectroscopy were used to characterize the phosphorylated and unphosphorylated forms of a peptide with the MARCKS sequence surrounding S25. The peptide phosphorylated at this residue is recognized by monoclonal antibody 3C3 (mAb 3C3). CD and NMR data indicated that S25 phosphorylation does not cause extensive modifications in the peptide structure. However, the sharper lines, the absence of multiple spin systems and relaxation dispersion data observed for the phosphorylated peptide suggested a more ordered structure. Surface Plasmon Resonance was employed to compare the binding properties of mAb 3C3 to MARCKS protein and peptide. SPR showed that mAb 3C3 binds to the whole protein and the peptide with a similar affinity, albeit different kinetics. The slightly ordered structure of the phosphorylated peptide might be at the origin of its ability to interact with mAb 3C3 antibody, but this binding did not noticeably modify the peptide structure.
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Affiliation(s)
- Luzineide W Tinoco
- Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco H, Rio de Janeiro 21941-902, RJ, Brazil.
| | - Jully L Fraga
- Instituto de Pesquisas de Produtos Naturais, Universidade Federal do Rio de Janeiro, Cidade Universitária, CCS, Bloco H, Rio de Janeiro 21941-902, RJ, Brazil.
| | - Cristiane D Anobom
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária, CT, Bloco A, Rio de Janeiro 21941-909, RJ, Brazil.
| | - Flavio R Zolessi
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
| | - Gonzalo Obal
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay.
| | - Andrea Toledo
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
| | - Otto Pritsch
- Unidad de Biofísica de Proteínas, Institut Pasteur de Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay.
| | - Cristina Arruti
- Laboratorio de Cultivo de Tejidos, Sección Biología Celular, DBCM, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay.
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Abstract
Actin exists as a monomer (G-actin) which can be polymerized to filaments) F-actin) that under the influence of actin-binding proteins and polycations bundle and contribute to the formation of the cytoskeleton. Bundled actin from lysed cells increases the viscosity of sputum in lungs of cystic fibrosis patients. The human host defense peptide LL-37 was previously shown to induce actin bundling and was thus hypothesized to contribute to the pathogenicity of this disease. In this work, interactions between actin and the cationic LL-37 were studied by optical, proteolytic and surface plasmon resonance methods and compared to those obtained with scrambled LL-37 and with the cationic protein lysozyme. We show that LL-37 binds strongly to CaATP-G-actin while scrambled LL-37 does not. While LL-37, at superstoichiometric LL-37/actin concentrations polymerizes MgATP-G-actin, at lower non-polymerizing concentrations LL-37 inhibits actin polymerization by MgCl2 or NaCl. LL-37 bundles Mg-F-actin filaments both at low and physiological ionic strength when in equimolar or higher concentrations than those of actin. The LL-37 induced bundles are significantly less sensitive to increase in ionic strength than those induced by scrambled LL-37 and lysozyme. LL-37 in concentrations lower than those needed for actin polymerization or bundling, accelerates cleavage of both monomer and polymer actin by subtilisin. Our results indicate that the LL-37-actin interaction is partially electrostatic and partially hydrophobic and that a specific actin binding sequence in the peptide is responsible for the hydrophobic interaction. LL-37-induced bundles, which may contribute to the accumulation of sputum in cystic fibrosis, are dissociated very efficiently by DNase-1 and also by cofilin.
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Mancek-Keber M, Bencina M, Japelj B, Panter G, Andrä J, Brandenburg K, Triantafilou M, Triantafilou K, Jerala R. MARCKS as a negative regulator of lipopolysaccharide signaling. THE JOURNAL OF IMMUNOLOGY 2012; 188:3893-902. [PMID: 22427633 DOI: 10.4049/jimmunol.1003605] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Myristoylated alanine-rich C kinase substrate (MARCKS) is an intrinsically unfolded protein with a conserved cationic effector domain, which mediates the cross-talk between several signal transduction pathways. Transcription of MARCKS is increased by stimulation with bacterial LPS. We determined that MARCKS and MARCKS-related protein specifically bind to LPS and that the addition of the MARCKS effector peptide inhibited LPS-induced production of TNF-α in mononuclear cells. The LPS binding site within the effector domain of MARCKS was narrowed down to a heptapeptide that binds to LPS in an extended conformation as determined by nuclear magnetic resonance spectroscopy. After LPS stimulation, MARCKS moved from the plasma membrane to FYVE-positive endosomes, where it colocalized with LPS. MARCKS-deficient mouse embryonic fibroblasts (MEFs) responded to LPS with increased IL-6 production compared with the matched wild-type MEFs. Similarly, small interfering RNA knockdown of MARCKS also increased LPS signaling, whereas overexpression of MARCKS inhibited LPS signaling. TLR4 signaling was enhanced by the ablation of MARCKS, which had no effect on stimulation by TLR2, TLR3, and TLR5 agonists. These findings demonstrate that MARCKS contributes to the negative regulation of the cellular response to LPS.
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Affiliation(s)
- Mateja Mancek-Keber
- Department of Biotechnology, National Institute of Chemistry, Ljubljana 1000, Slovenia
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Tanabe A, Shiraishi M, Negishi M, Saito N, Tanabe M, Sasaki Y. MARCKS dephosphorylation is involved in bradykinin-induced neurite outgrowth in neuroblastoma SH-SY5Y cells. J Cell Physiol 2012; 227:618-29. [PMID: 21448919 DOI: 10.1002/jcp.22763] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bradykinin (BK) plays a major role in producing peripheral sensitization in response to peripheral inflammation and in pain transmission in the central nerve system (CNS). Because BK activates protein kinase C (PKC) through phospholipase C (PLC)-β and myristoylated alanine-rich C kinase substrate (MARCKS) has been found to be a substrate of PKC, we explored the possibility that BK could induce MARCKS phosphorylation and regulate its function. BK stimulation induced transient MARCKS phosphorylation on Ser159 with a peak at 1 min in human neuroblastoma SH-SY5Y cells. By contrast, PKC activation by the phorbol ester phorbol 12,13-dibutyrate (PDBu) elicited MARCKS phosphorylation which lasted more than 10 min. Western blotting analyses and glutathione S-transferase (GST) pull-down analyses showed that the phosphorylation by BK was the result of activation of the PKC-dependent RhoA/Rho-associated coiled-coil kinase (ROCK) pathway. Protein phosphatase (PP) 2A inhibitors calyculin A and fostriecin inhibited the dephosphorylation of MARCKS after BK-induced phosphorylation. Moreover, immunoprecipitation analyses showed that PP2A interacts with MARCKS. These results indicated that PP2A is the dominant PP of MARCKS after BK stimulation. We established SH-SY5Y cell lines expressing wild-type MARCKS and unphosphorylatable MARCKS, and cell morphology changes after cell stimulation were studied. PDBu induced lamellipodia formation on the neuroblastoma cell line SH-SY5Y and the morphology was sustained, whereas BK induced neurite outgrowth of the cells via lamellipodia-like actin accumulation that depended on transient MARCKS phosphorylation. Thus these findings show a novel BK signal cascade-that is, BK promotes neurite outgrowth through transient MARCKS phosphorylation involving the PKC-dependent RhoA/ROCK pathway and PP2A in a neuroblastoma cell line.
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Affiliation(s)
- Atsuhiro Tanabe
- Laboratory of Pharmacology, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, Japan.
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Muhlrad A, Grintsevich EE, Reisler E. Polycation induced actin bundles. Biophys Chem 2011; 155:45-51. [PMID: 21411219 DOI: 10.1016/j.bpc.2011.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 02/18/2011] [Accepted: 02/19/2011] [Indexed: 01/17/2023]
Abstract
Three polycations, polylysine, the polyamine spermine and the polycationic protein lysozyme were used to study the formation, structure, ionic strength sensitivity and dissociation of polycation-induced actin bundles. Bundles form fast, simultaneously with the polymerization of MgATP-G-actins, upon the addition of polycations to solutions of actins at low ionic strength conditions. This indicates that nuclei and/or nascent filaments bundle due to attractive, electrostatic effect of polycations and the neutralization of repulsive interactions of negative charges on actin. The attractive forces between the filaments are strong, as shown by the low (in nanomolar range) critical concentration of their bundling at low ionic strength. These bundles are sensitive to ionic strength and disassemble partially in 100 mM NaCl, but both the dissociation and ionic strength sensitivity can be countered by higher polycation concentrations. Cys374 residues of actin monomers residing on neighboring filaments in the bundles can be cross-linked by the short span (5.4Å) MTS-1 (1,1-methanedyl bismethanethiosulfonate) cross-linker, which indicates a tight packing of filaments in the bundles. The interfilament cross-links, which connect monomers located on oppositely oriented filaments, prevent disassembly of bundles at high ionic strength. Cofilin and the polysaccharide polyanion heparin disassemble lysozyme induced actin bundles more effectively than the polylysine-induced bundles. The actin-lysozyme bundles are pathologically significant as both proteins are found in the pulmonary airways of cystic fibrosis patients. Their bundles contribute to the formation of viscous mucus, which is the main cause of breathing difficulties and eventual death in this disorder.
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Affiliation(s)
- Andras Muhlrad
- Institute of Dental Sciences, School of Dental Medicine, The Hebrew University, Jerusalem 91120, Israel.
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Woodling KA, Eyler JR, Tsybin YO, Nilsson CL, Marshall AG, Edison AS, Al-Naggar IM, Bubb MR. Identification of single and double sites of phosphorylation by ECD FT-ICR/MS in peptides related to the phosphorylation site domain of the myristoylated alanine-rich C kinase protein. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:2137-2145. [PMID: 17962038 DOI: 10.1016/j.jasms.2007.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 09/16/2007] [Accepted: 09/17/2007] [Indexed: 05/25/2023]
Abstract
A series of phosphorylated test peptides was studied by electron capture dissociation Fourier transform ion cyclotron resonance mass spectrometry (ECD FT-ICR MS). The extensive ECD-induced fragmentation made identification of phosphorylation sites for these peptides straightforward. The site(s) of initial phosphorylation of a synthetic peptide with a sequence identical to that of the phosphorylation site domain (PSD) of the myristoylated alanine-rich C kinase (MARCKS) protein was then determined. Despite success in analyzing fragmentation of the smaller test peptides, a unique site on the PSD for the first step of phosphorylation could not be identified because the phosphorylation reaction produced a heterogeneous mixture of products. Some molecules were phosphorylated on the serine closest to the N-terminus, and others on one of the two serines closest to the C-terminus of the peptide. Although no definitive evidence for phosphorylation on either of the remaining two serines in the PSD was found, modification there could not be ruled out by the ECD fragmentation data.
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Affiliation(s)
- Kellie A Woodling
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, USA
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13
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Gatlin JC, Estrada-Bernal A, Sanford SD, Pfenninger KH. Myristoylated, alanine-rich C-kinase substrate phosphorylation regulates growth cone adhesion and pathfinding. Mol Biol Cell 2006; 17:5115-30. [PMID: 16987960 PMCID: PMC1679677 DOI: 10.1091/mbc.e05-12-1183] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Repellents evoke growth cone turning by eliciting asymmetric, localized loss of actin cytoskeleton together with changes in substratum attachment. We have demonstrated that semaphorin-3A (Sema3A)-induced growth cone detachment and collapse require eicosanoid-mediated activation of protein kinase C epsilon (PKC epsilon) and that the major PKC epsilon target is the myristoylated, alanine-rich C-kinase substrate (MARCKS). Here, we show that PKC activation is necessary for growth cone turning and that MARCKS, while at the membrane, colocalizes with alpha3-integrin in a peripheral adhesive zone of the growth cone. Phosphorylation of MARCKS causes its translocation from the membrane to the cytosol. Silencing MARCKS expression dramatically reduces growth cone spread, whereas overexpression of wild-type MARCKS inhibits growth cone collapse triggered by PKC activation. Expression of phosphorylation-deficient, mutant MARCKS greatly expands growth cone adhesion, and this is characterized by extensive colocalization of MARCKS and alpha3-integrin, resistance to eicosanoid-triggered detachment and collapse, and reversal of Sema3A-induced repulsion into attraction. We conclude that MARCKS is involved in regulating growth cone adhesion as follows: its nonphosphorylated form stabilizes integrin-mediated adhesions, and its phosphorylation-triggered release from adhesions causes localized growth cone detachment critical for turning and collapse.
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Affiliation(s)
- Jesse C. Gatlin
- Departments of Pediatrics and of Cell and Developmental Biology, University of Colorado School of Medicine, and University of Colorado Cancer Center, Aurora, CO 80045
| | - Adriana Estrada-Bernal
- Departments of Pediatrics and of Cell and Developmental Biology, University of Colorado School of Medicine, and University of Colorado Cancer Center, Aurora, CO 80045
| | - Staci D. Sanford
- Departments of Pediatrics and of Cell and Developmental Biology, University of Colorado School of Medicine, and University of Colorado Cancer Center, Aurora, CO 80045
| | - Karl H. Pfenninger
- Departments of Pediatrics and of Cell and Developmental Biology, University of Colorado School of Medicine, and University of Colorado Cancer Center, Aurora, CO 80045
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Hussain RJ, Stumpo DJ, Blackshear PJ, Lenox RH, Abel T, McNamara RK. Myristoylated alanine rich C kinase substrate (MARCKS) heterozygous mutant mice exhibit deficits in hippocampal mossy fiber-CA3 long-term potentiation. Hippocampus 2006; 16:495-503. [PMID: 16572394 PMCID: PMC2914311 DOI: 10.1002/hipo.20177] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The myristoylated alanine-rich C kinase substrate (MARCKS) is a primary protein kinase C (PKC) substrate in brain thought to transduce PKC signaling into alterations in the filamentous (F) actin cytoskeleton. Within the adult hippocampus, MARCKS is highly expressed in the dentate gyrus (DG)-CA3 mossy fiber pathway, but is expressed at low levels in the CA3-CA1 Schaffer collateral-CA1 pathway. We have previously demonstrated that 50% reductions in MARCKS expression in heterozygous Marcks mutant mice produce robust deficits in spatial reversal learning, but not contextual fear conditioning, suggesting that only specific aspects of hippocampal function are impaired by reduction in MARCKS expression. To further elucidate the role of MARCKS in hippocampal synaptic plasticity, in the present study we examined basal synaptic transmission, paired-pulse facilitation, post-tetanic potentiation, and long-term potentiation (LTP) in the hippocampal mossy fiber-CA3 and Schaffer collateral-CA1 pathways of heterozygous Marcks mutant and wild-type mice. We found that LTP is significantly impaired in the mossy fiber-CA3 pathway, but not in the Schaffer collateral-CA1 pathway, in heterozygous Marcks mutant mice, whereas basal synaptic transmission, paired-pulse facilitation, and post-tetanic potentiation are unaffected in both pathways. These findings indicate that a 50% reduction in MARCKS expression impairs processes required for long-term, but not short-term, synaptic plasticity in the mossy fiber-CA3 pathway. The implications of these findings for the role of the mossy fiber-CA3 pathway in hippocampus-dependent learning processes are discussed.
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Affiliation(s)
- Rifat J. Hussain
- Department of Psychiatry, University of Pennsylvania School of Medicine, Clinical Research Building, Philadelphia, Pennsylvania
| | - Deborah J. Stumpo
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Perry J. Blackshear
- National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
| | - Robert H. Lenox
- Department of Psychiatry, University of Pennsylvania School of Medicine, Clinical Research Building, Philadelphia, Pennsylvania
| | - Ted Abel
- Department of Biology, 319 Leidy Labs, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Robert K. McNamara
- Department of Psychiatry, University of Cincinnati College of Medicine, Medical Science Building, Cincinnati, Ohio
- Correspondence to: Robert K. McNamara, Ph.D., Department of Psychiatry, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267-0559.
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15
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Tapp H, Al-Naggar IM, Yarmola EG, Harrison A, Shaw G, Edison AS, Bubb MR. MARCKS is a natively unfolded protein with an inaccessible actin-binding site: evidence for long-range intramolecular interactions. J Biol Chem 2005; 280:9946-56. [PMID: 15640140 DOI: 10.1074/jbc.m414614200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myristoylated alanine-rich C kinase substrate (MARCKS) is an unfolded protein that contains well characterized actin-binding sites within the phosphorylation site domain (PSD), yet paradoxically, we now find that intact MARCKS does not bind to actin. Intact MARCKS also does not bind as well to calmodulin as does the PSD alone. Myristoylation at the N terminus alters how calmodulin binds to MARCKS, implying that, despite its unfolded state, the distant N terminus influences binding events at the PSD. We show that the free PSD binds with site specificity to MARCKS, suggesting that long-range intramolecular interactions within MARCKS are also possible. Because of the unusual primary sequence of MARCKS with an overall isoelectric point of 4.2 yet a very basic PSD (overall charge of +13), we speculated that ionic interactions between oppositely charged domains of MARCKS were responsible for long-range interactions within MARCKS that sterically influence binding events at the PSD and that explain the observed differences between properties of the PSD and MARCKS. Consistent with this hypothesis, chemical modifications of MARCKS that neutralize negatively charged residues outside of the PSD allow the PSD to bind to actin and increase the affinity of MARCKS for calmodulin. Similarly, both myristoylation of MARCKS and cleavage of MARCKS by calpain are shown to increase the availability of the PSD so as to activate its actin-binding activity. Because abundant evidence supports the conclusion that MARCKS is an important protein in regulating actin dynamics, our data imply that post-translational modifications of MARCKS are necessary and sufficient to regulate actin-binding activity.
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Affiliation(s)
- Hazel Tapp
- Department of Medicine, University of Florida College of Medicine, Gainesville, Florida 32610, USA
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16
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Mosevitsky MI. Nerve Ending “Signal” Proteins GAP‐43, MARCKS, and BASP1. INTERNATIONAL REVIEW OF CYTOLOGY 2005; 245:245-325. [PMID: 16125549 DOI: 10.1016/s0074-7696(05)45007-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanisms of growth cone pathfinding in the course of neuronal net formation as well as mechanisms of learning and memory have been under intense investigation for the past 20 years, but many aspects of these phenomena remain unresolved and even mysterious. "Signal" proteins accumulated mainly in the axon endings (growth cones and the presynaptic area of synapses) participate in the main brain processes. These proteins are similar in several essential structural and functional properties. The most prominent similarities are N-terminal fatty acylation and the presence of an "effector domain" (ED) that dynamically binds to the plasma membrane, to calmodulin, and to actin fibrils. Reversible phosphorylation of ED by protein kinase C modulates these interactions. However, together with similarities, there are significant differences among the proteins, such as different conditions (Ca2+ contents) for calmodulin binding and different modes of interaction with the actin cytoskeleton. In light of these facts, we consider GAP-43, MARCKS, and BASP1 both separately and in conjunction. Special attention is devoted to a discussion of apparent inconsistencies in results and opinions of different authors concerning specific questions about the structure of proteins and their interactions.
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Affiliation(s)
- Mark I Mosevitsky
- Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina Leningrad District, Russian Federation
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17
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McNamara RK, Lenox RH. The myristoylated alanine-rich C kinase substrate: a lithium-regulated protein linking cellular signaling and cytoskeletal plasticity. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.cnr.2004.09.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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Disatnik MH, Boutet SC, Pacio W, Chan AY, Ross LB, Lee CH, Rando TA. The bi-directional translocation of MARCKS between membrane and cytosol regulates integrin-mediated muscle cell spreading. J Cell Sci 2004; 117:4469-79. [PMID: 15316066 DOI: 10.1242/jcs.01309] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The regulation of the cytoskeleton is critical to normal cell function during tissue morphogenesis. Cell-matrix interactions mediated by integrins regulate cytoskeletal dynamics, but the signaling cascades that control these processes remain largely unknown. Here we show that myristoylated alanine-rich C-kinase substrate (MARCKS) a specific substrate of protein kinase C (PKC), is regulated by alpha5beta1 integrin-mediated activation of PKC and is critical to the regulation of actin stress fiber formation during muscle cell spreading. Using MARCKS mutants that are defective in membrane association or responsiveness to PKC-dependent phosphorylation, we demonstrate that the translocation of MARCKS from the membrane to the cytosol in a PKC-dependent manner permits the initial phases of cell adhesion. The dephosphorylation of MARCKS and its translocation back to the membrane permits the later stages of cell spreading during the polymerization and cross-linking of actin and the maturation of the cytoskeleton. All of these processes are directly dependent on the binding of alpha5beta1 integrin to its extracellular matrix receptor, fibronectin. These results demonstrate a direct biochemical pathway linking alpha5beta1 integrin signaling to cytoskeletal dynamics and involving bi-directional translocation of MARCKS during the dramatic changes in cellular morphology that occur during cell migration and tissue morphogenesis.
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Affiliation(s)
- Marie-Hélène Disatnik
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5235, USA
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19
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Dedieu S, Poussard S, Mazères G, Grise F, Dargelos E, Cottin P, Brustis JJ. Myoblast migration is regulated by calpain through its involvement in cell attachment and cytoskeletal organization. Exp Cell Res 2004; 292:187-200. [PMID: 14720518 DOI: 10.1016/j.yexcr.2003.08.014] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cell migration is a fundamental cellular function particularly during skeletal muscle development. Ubiquitous calpains are well known to play a pivotal role during muscle differentiation, especially at the onset of fusion. In this study, the possible positive regulation of myoblast migration by calpains, a crucial step required to align myoblasts to permit them to fuse, was investigated. Inhibition of calpain activity by different pharmacological inhibitors argues for the involvement of these proteinases during the migration of myoblasts. Moreover, a clonal cell line that fourfold overexpresses calpastatin, the endogenous inhibitor of calpains, and that exhibits deficient calpain activities was obtained. The results showed that the migratory capacity of C2C12 and fusion into multinucleated myotubes were completely prevented in these clonal cells. Calpastatin-overexpressing myoblasts unable to migrate were characterized by rounded morphology, the loss of membrane extensions, the disorganization of stress fibers and exhibited a major defect in new adhesion formation. Surprisingly, the proteolytic patterns of desmin, talin, vinculin, focal adhesion kinase (FAK) and ezrin, radixin, moesin (ERM) proteins are the same in calpastatin-overexpressing myoblasts as compared to control cells. However, an important accumulation of myristoylated alanine-rich C kinase substrate (MARCKS) was observed in cells showing a reduced calpain activity, suggesting that the proteolysis of this actin-binding protein is calpain-dependent and could be involved in both myoblast adhesion and migration.
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Affiliation(s)
- Stéphane Dedieu
- Laboratoire Biosciences de l'Aliment, Université Bordeaux I, ISTAB USC INRA 429, 33405 Talence Cedex, France
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20
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Luo B, Prescott SM, Topham MK. Association of diacylglycerol kinase zeta with protein kinase C alpha: spatial regulation of diacylglycerol signaling. J Cell Biol 2003; 160:929-37. [PMID: 12629049 PMCID: PMC2173768 DOI: 10.1083/jcb.200208120] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Activation of PKC depends on the availability of DAG, a signaling lipid that is tightly and dynamically regulated. DAG kinase (DGK) terminates DAG signaling by converting it to phosphatidic acid. Here, we demonstrate that DGKzeta inhibits PKCalpha activity and that DGK activity is required for this inhibition. We also show that DGKzeta directly interacts with PKCalpha in a signaling complex and that the binding site in DGKzeta is located within the catalytic domain. Because PKCalpha can phosphorylate the myristoylated alanine-rich C-kinase substrate (MARCKS) motif of DGKzeta, we tested whether this modification could affect their interaction. Phosphorylation of this motif significantly attenuated coimmunoprecipitation of DGKzeta and PKCalpha and abolished their colocalization in cells, indicating that it negatively regulates binding. Expression of a phosphorylation-mimicking DGKzeta mutant that was unable to bind PKCalpha did not inhibit PKCalpha activity. Together, our results suggest that DGKzeta spatially regulates PKCalpha activity by attenuating local accumulation of signaling DAG. This regulation is impaired by PKCalpha-mediated DGKzeta phosphorylation.
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Affiliation(s)
- Bai Luo
- The Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA.
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21
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Yamauchi E, Nakatsu T, Matsubara M, Kato H, Taniguchi H. Crystal structure of a MARCKS peptide containing the calmodulin-binding domain in complex with Ca2+-calmodulin. Nat Struct Mol Biol 2003; 10:226-31. [PMID: 12577052 DOI: 10.1038/nsb900] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2002] [Accepted: 12/30/2002] [Indexed: 11/09/2022]
Abstract
The calmodulin-binding domain of myristoylated alanine-rich C kinase substrate (MARCKS), which interacts with various targets including calmodulin, actin and membrane lipids, has been suggested to function as a crosstalk point among several signal transduction pathways. We present here the crystal structure at 2 A resolution of a peptide consisting of the MARCKS calmodulin (CaM)-binding domain in complex with Ca2+-CaM. The domain assumes a flexible conformation, and the hydrophobic pocket of the calmodulin N-lobe, which is a common CaM-binding site observed in previously resolved Ca2+-CaM-target peptide complexes, is not involved in the interaction. The present structure presents a novel target-recognition mode of calmodulin and provides insight into the structural basis of the flexible interaction module of MARCKS.
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Affiliation(s)
- Emiko Yamauchi
- Harima Institute at SPring-8, RIKEN, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
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22
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Corradin S, Ransijn A, Corradin G, Bouvier J, Delgado MB, Fernandez-Carneado J, Mottram JC, Vergères G, Mauël J. Novel peptide inhibitors of Leishmania gp63 based on the cleavage site of MARCKS (myristoylated alanine-rich C kinase substrate)-related protein. Biochem J 2002; 367:761-9. [PMID: 12137567 PMCID: PMC1222923 DOI: 10.1042/bj20020386] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2002] [Revised: 06/19/2002] [Accepted: 07/23/2002] [Indexed: 11/17/2022]
Abstract
The zinc metalloprotease gp63 (leishmanolysin; promastigote surface protease) is expressed at high density at the surface of Leishmania promastigotes. Efficient non-toxic inhibitors of gp63 do not exist, and its precise role in parasite physiology remains unknown. MARCKS (myristoylated alanine-rich C kinase substrate) and MARCKS-related protein (MRP; MacMARCKS) are protein kinase C substrates in various cells, including macrophages. We reported previously that MRP is an excellent substrate for gp63. A major cleavage site was identified within the MRP effector domain (ED), a highly basic 24-amino-acid sequence, and the synthetic ED peptide (MRP(ED)) was shown to inhibit MRP hydrolysis. In the present study, MRP cleavage was used as an assay to measure the capacity of various MRP or MARCKS ED peptides to block gp63 activity. On a molar basis, MRP(ED) inhibited gp63 to a greater extent than two previously described gp63 inhibitors, o -phenanthroline and benzyloxycarbonyl-Tyr-Leu-NHOH. MARCKS(ED) analogues containing modifications in the gp63 consensus cleavage site showed significant differences in inhibitory capacity. As phosphorylation of ED serine residues prevented gp63-mediated MRP degradation, we synthesized a pseudophosphorylated peptide in which serine residues were substituted by aspartate (3DMRP(ED)). 3DMRP(ED) was a highly effective inhibitor of both soluble and parasite-associated gp63. Finally, MRP ED peptides were synthesized together with an N-terminal HIV-1 Tat transduction domain (TD) to obtain cell-permeant peptide constructs. Such peptides retained gp63 inhibitory activity and efficiently entered both macrophages and parasites in a Tat TD-dependent manner. These studies may provide the basis for developing potent cell-permeant inhibitors of gp63.
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Affiliation(s)
- Sally Corradin
- Institute of Biochemistry, University of Lausanne, Chemin de Boveresses, 1066 Epalinges, Switzerland.
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23
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Wang J, Gambhir A, Hangyás-Mihályné G, Murray D, Golebiewska U, McLaughlin S. Lateral sequestration of phosphatidylinositol 4,5-bisphosphate by the basic effector domain of myristoylated alanine-rich C kinase substrate is due to nonspecific electrostatic interactions. J Biol Chem 2002; 277:34401-12. [PMID: 12097325 DOI: 10.1074/jbc.m203954200] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A peptide corresponding to the basic (+13), unstructured effector domain of myristoylated alanine-rich C kinase substrate (MARCKS) binds strongly to membranes containing phosphatidylinositol 4,5-bisphosphate (PIP(2)). Although aromatic residues contribute to the binding, three experiments suggest the binding is driven mainly by nonspecific local electrostatic interactions. First, peptides with 13 basic residues, Lys-13 and Arg-13, bind to PIP(2)-containing vesicles with the same high affinity as the effector domain peptide. Second, removing basic residues from the effector domain peptide reduces the binding energy by an amount that correlates with the number of charges removed. Third, peptides corresponding to a basic region in GAP43 and MARCKS effector domain-like regions in other proteins (e.g. MacMARCKS, adducin, Drosophila A kinase anchor protein 200, and N-methyl-d-aspartate receptor) also bind with an energy that correlates with the number of basic residues. Kinetic measurements suggest the effector domain binds to several PIP(2). Theoretical calculations show the effector domain produces a local positive potential, even when bound to a bilayer with 33% monovalent acidic lipids, and should thus sequester PIP(2) laterally. This electrostatic sequestration was observed experimentally using a phospholipase C assay. Our results are consistent with the hypothesis that MARCKS could reversibly sequester much of the PIP(2) in the plasma membrane.
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Affiliation(s)
- Jiyao Wang
- Department of Physiology and Biophysics, State University of New York, Stony Brook, New York 11794-8661, USA
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Regulation of A-kinase anchoring protein 79/150-cAMP-dependent protein kinase postsynaptic targeting by NMDA receptor activation of calcineurin and remodeling of dendritic actin. J Neurosci 2002. [PMID: 12177200 DOI: 10.1523/jneurosci.22-16-07027.2002] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
At the postsynaptic membrane of glutamatergic synapses, the cAMP-dependent protein kinase (PKA), protein kinase C (PKC), and calcineurin (CaN) anchoring protein AKAP79/150 is recruited to NMDA and AMPA glutamate receptors by postsynaptic density (PSD)-95 family membrane-associated guanylate kinase (MAGUK) scaffold proteins. These signaling scaffold complexes may function to regulate receptor phosphorylation in synaptic plasticity. Thus, it is important to understand regulation of AKAP79/150 targeting to synapses and recruitment to PSD-MAGUK complexes. AKAP79 is targeted to the plasma membrane by an N-terminal basic domain that binds phosphatidylinositol-4,5-bisphosphate (PI-4,5-P(2)) and is regulated by PKC phosphorylation and calmodulin binding. Here we demonstrate that this same domain also binds F-actin in a calmodulin- and PKC-regulated manner, targets to membrane ruffles enriched in F-actin and PI-4,5-P(2) in COS7 cells, and localizes to dendritic spines with F-actin and PSD-MAGUKs in hippocampal neurons. Inhibition of actin polymerization disrupted AKAP79 targeting of PKA and CaN to ruffles in COS7 cells and endogenous AKAP79/150 dendritic spine localization with PKA, CaN, and PSD-MAGUKs in neurons. AKAP79/150 postsynaptic localization was rapidly regulated by NMDA receptors through CaN activation and F-actin remodeling, further suggesting that AKAP79/150 signaling scaffold targeting depends on actin dynamics. NMDA receptor activation also regulated dendritic spine localization of PKA and CaN and association of the AKAP79/150-PKA complex with PSD-MAGUKs. Because AMPA receptor PKA phosphorylation and synaptic localization are regulated by similar NMDA receptor-CaN signaling pathways linked to hippocampal long-term depression, this regulation of AKAP79/150 postsynaptic targeting might be important for synaptic plasticity.
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25
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Qian Y, Baisden JM, Cherezova L, Summy JM, Guappone-Koay A, Shi X, Mast T, Pustula J, Zot HG, Mazloum N, Lee MY, Flynn DC. PC phosphorylation increases the ability of AFAP-110 to cross-link actin filaments. Mol Biol Cell 2002; 13:2311-22. [PMID: 12134071 PMCID: PMC117315 DOI: 10.1091/mbc.e01-12-0148] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2001] [Revised: 04/02/2002] [Accepted: 04/12/2002] [Indexed: 11/11/2022] Open
Abstract
The actin filament-associated protein and Src-binding partner, AFAP-110, is an adaptor protein that links signaling molecules to actin filaments. AFAP-110 binds actin filaments directly and multimerizes through a leucine zipper motif. Cellular signals downstream of Src(527F) can regulate multimerization. Here, we determined recombinant AFAP-110 (rAFAP-110)-bound actin filaments cooperatively, through a lateral association. We demonstrate rAFAP-110 has the capability to cross-link actin filaments, and this ability is dependent on the integrity of the carboxy terminal actin binding domain. Deletion of the leucine zipper motif or PKC phosphorylation affected AFAP-110's conformation, which correlated with changes in multimerization and increased the capability of rAFAP-110 to cross-link actin filaments. AFAP-110 is both a substrate and binding partner of PKC. On PKC activation, stress filament organization is lost, motility structures form, and AFAP-110 colocalizes strongly with motility structures. Expression of a deletion mutant of AFAP-110 that is unable to bind PKC blocked the effect of PMA on actin filaments. We hypothesize that upon PKC activation, AFAP-110 can be cooperatively recruited to newly forming actin filaments, like those that exist in cell motility structures, and that PKC phosphorylation effects a conformational change that may enable AFAP-110 to promote actin filament cross-linking at the cell membrane.
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Affiliation(s)
- Yong Qian
- The Mary Babb Randolph Cancer Center and the Department of Microbiology and Immunology, West Virginia University, Morgantown, West Virginia 26506-9300, USA
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26
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Curtis M, Nikolopoulos SN, Turner CE. Actopaxin is phosphorylated during mitosis and is a substrate for cyclin B1/cdc2 kinase. Biochem J 2002; 363:233-42. [PMID: 11931650 PMCID: PMC1222471 DOI: 10.1042/0264-6021:3630233] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Prior to cell division, normal adherent cells adopt a round morphology that is associated with a loss of actin stress fibres and disassembly of focal adhesions. In this study, we investigate the mitotic phosphorylation of the recently described paxillin and actin-binding focal-adhesion protein actopaxin [Nikolopoulos and Turner (2000) J. Cell Biol. 151, 1435-1448]. Actopaxin is comprised of an N-terminus containing six putative cdc2 phosphorylation sites and a C-terminus consisting of tandem calponin homology domains. Here we show that the N-terminus of actopaxin is phosphorylated by cyclin B1/cdc2 kinase in vitro and that this region of actopaxin precipitates cdc2 kinase activity from mitotic lysates. Actopaxin exhibits reduced electrophoretic mobility during mitosis that is dependent on phosphorylation within the first two consensus cdc2 phosphorylation sites. Finally, as cells progress from mitosis to G(1) there is an adhesion-independent dephosphorylation of actopaxin, suggesting that actopaxin dephosphorylation precedes cell spreading and the reformation of focal adhesions. Taken together, these results suggest a role for cyclin B1/cdc2-dependent phosphorylation of actopaxin in regulating actin cytoskeleton reorganization during cell division.
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Affiliation(s)
- Michael Curtis
- Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, U.S.A
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27
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Sukumaran SK, Prasadarao NV. Regulation of protein kinase C in Escherichia coli K1 invasion of human brain microvascular endothelial cells. J Biol Chem 2002; 277:12253-62. [PMID: 11805101 DOI: 10.1074/jbc.m110740200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Escherichia coli is one of the most important pathogens involved in the development of neonatal meningitis in many parts of the world. Traversal of E. coli across the blood-brain barrier is a crucial event in the pathogenesis of E. coli meningitis. Our previous studies have shown that outer membrane protein A (OmpA) expression is necessary in E. coli for a mechanism involving actin filaments in its passage through the endothelial cells. Focal adhesion kinase (FAK) and phosphatidylinositol 3-kinase (PI3K) have also been activated in host cells during the process of invasion. In an attempt to elucidate the mechanisms leading to actin filament condensation, we have focused our attention on protein kinase C (PKC), an enzyme central to many signaling events, including actin rearrangement. In the current study, specific PKC inhibitors, bisindolmaleimide and a PKC-inhibitory peptide, inhibited E. coli invasion of human brain microvascular endothelial cells (HBMEC) by more than 75% in a dose-dependent manner, indicating a significant role played by this enzyme in the invasion process. Our results further showed that OmpA+ E. coli induces significant activation of PKC in HBMEC as measured by the PepTag nonradioactive assay. In addition, we identified that the PKC isoform activated in E. coli invasion is a member of the conventional family of PKC, PKC-alpha, which requires calcium for activation. Immunocytochemical studies have indicated that the activated PKC-alpha is associated with actin condensation beneath the bacterial entry site. Overexpression of a dominant negative mutant of PKC-alpha in HBMEC abolished the E. coli invasion without significant changes in FAK phosphorylation or PI3K activity patterns. In contrast, in HBMEC overexpressing the mutant forms of either FAK or PI3K, E. coli-induced PKC activation was significantly blocked. Furthermore, our studies showed that activation of PKC-alpha induces the translocation of myristoylated alanine-rich protein kinase C substrate, an actin cross-linking protein and a substrate for PKC-alpha, from the membrane to cytosol. This is the first report of FAK- and PI3K-dependent PKC-alpha activation in bacterial invasion related to cytoskeletal reorganization.
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Affiliation(s)
- Sunil K Sukumaran
- Division of Infectious Diseases, Childrens Hospital Los Angeles and Keck School of Medicine, University of Southern California, Los Angeles, California 90027, USA
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Ikenoya M, Hidaka H, Hosoya T, Suzuki M, Yamamoto N, Sasaki Y. Inhibition of rho-kinase-induced myristoylated alanine-rich C kinase substrate (MARCKS) phosphorylation in human neuronal cells by H-1152, a novel and specific Rho-kinase inhibitor. J Neurochem 2002; 81:9-16. [PMID: 12067241 DOI: 10.1046/j.1471-4159.2002.00801.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The functions of small G protein Rho-associated kinase (Rho-kinase) have been determined in muscle and non-muscle cells, but, particularly in neuronal cells, its effector(s) has not been well known. Recently, we preliminarily reported that Rho-kinase phosphorylates the Ser159 residue in myristoylated alanine-rich C kinase substrate (MARCKS) in vitro, but it remains obscure in vivo. To further clarify this point, we developed an isoquinolinesulfonamide derivative, H-1152, that is a more specific, stronger and membrane-permeable inhibitor of Rho-kinase with a Ki value of 1.6 nM, but poor inhibitor of other serine/threonine kinases. H-1152 dose-dependently inhibited the phosphorylation of MARCKS in human neuroteratoma (NT-2) cells stimulated by Rho-activator lysophosphatidic acid (LPA), which was determined by phosphorylation site-specific antibody against phospho-Ser159 in MARCKS, whereas it hardly inhibited the phosphorylation stimulated by phorbol-12,13-dibutyrate (PDBu). In contrast, two other Rho-kinase inhibitors, HA-1077 at 30 microM and Y-27632 at 10-30 microM, inhibited the phosphorylation of MARCKS in the cells stimulated by LPA and PDBu. A PKC inhibitor Ro-31-8220 selectively inhibited PDBu-induced phosphorylation of MARCKS. Taken together with our previous results, the present findings strongly suggest that Rho/Rho-kinase phosphorylates MARCKS at Ser159 residue in neuronal cells in response to LPA stimulation and that H-1152 is a useful tool to confirm Rho-kinase function(s) in cells and tissues.
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Affiliation(s)
- Mami Ikenoya
- Department of Microbiology and Molecular Virology, School of Medicine, Tokyo Medical and Dental University, Japan
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Abstract
The proteins of the MARCKS (myristoylated alanine-rich C kinase substrate) family were first identified as prominent substrates of protein kinase C (PKC). Since then, these proteins have been implicated in the regulation of brain development and postnatal survival, cellular migration and adhesion, as well as endo-, exo- and phago-cytosis, and neurosecretion. The effector domain of MARCKS proteins is phosphorylated by PKC, binds to calmodulin and contributes to membrane binding. This multitude of mutually exclusive interactions allows cross-talk between the signal transduction pathways involving PKC and calmodulin. This review focuses on recent, mostly biophysical and biochemical results renewing interest in this protein family. MARCKS membrane binding is now understood at the molecular level. From a structural point of view, there is a consensus emerging that MARCKS proteins are "natively unfolded". Interestingly, domains similar to the effector domain have been discovered in other proteins. Furthermore, since the effector domain enhances the polymerization of actin in vitro, MARCKS proteins have been proposed to mediate regulation of the actin cytoskeleton. However, the recent observations that MARCKS might serve to sequester phosphatidylinositol 4,5-bisphosphate in the plasma membrane of unstimulated cells suggest an alternative model for the control of the actin cytoskeleton. While myristoylation is classically considered to be a co-translational, irreversible event, new reports on MARCKS proteins suggest a more dynamic picture of this protein modification. Finally, studies with mice lacking MARCKS proteins have investigated the functions of these proteins during embryonic development in the intact organism.
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Affiliation(s)
- Anna Arbuzova
- Department of Physiology and Biophysics, Health Sciences Center, State University of New York, Stony Brook, NY 11794-8661, U.S.A
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Wang L, Liu X, Lenox RH. Transcriptional down-regulation of MARCKS gene expression in immortalized hippocampal cells by lithium. J Neurochem 2001; 79:816-25. [PMID: 11723174 DOI: 10.1046/j.1471-4159.2001.00631.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The gene (Macs) for the mouse myristoylated alanine-rich C kinase substrate (MARCKS) encodes a prominent substrate for protein kinase C that has been implicated in processes requiring signal dependent changes in actin-membrane plasticity and cytoskeletal restructuring. We have previously demonstrated that MARCKS protein is significantly down-regulated in rat hippocampus and in an immortalized hippocampal cell line (HN33.dw) following long-term exposure to lithium at clinically relevant concentrations (1 mM). Our current studies have examined transcriptional and post-transcriptional events that may underlie the lithium-induced down-regulation of MARCKS protein in the cultured hippocampal cell model system. MARCKS mRNA and protein expression were found to be concomitantly down-regulated following exposure of the HN33.dw cells to chronic lithium. Whereas the stability of MARCKS mRNA remained unchanged in the presence of lithium, nuclear run-off assay indicated that the transcription of nascent MARCKS mRNA was significantly reduced (approximately 50%) in the cells that had been treated with lithium for 7 days. Transient transfection of HN33.dw cells with a mouse cloned Macs promoter (993-bp) showed that the Macs promoter activity was attenuated to the same extent after chronic (7-10 days), but not subacute (24 h), lithium exposure. The inhibition of the Macs promoter was found to be dependent upon the presence of a 280-bp promoter region between -993-bp and -713-bp relative to the translation start site, suggesting that this region is a potential lithium-responsive region of Macs promoter (LRR). Mutant promoter lacking the LRR not only did not respond to chronic lithium exposure but also had significantly reduced promoter activity, suggesting that chronic lithium exposure represses the transcriptional activity of activator(s) bound to the promoter. Taken together, our data indicate that transcriptional inhibition of the Macs gene underlies the lithium-induced down-regulation of MARCKS expression in the immortalized hippocampal cells.
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Affiliation(s)
- L Wang
- Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Baisden JM, Qian Y, Zot HM, Flynn DC. The actin filament-associated protein AFAP-110 is an adaptor protein that modulates changes in actin filament integrity. Oncogene 2001; 20:6435-47. [PMID: 11607843 DOI: 10.1038/sj.onc.1204784] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The actin filament-associated protein of 110 kDa (AFAP-110) was first identified as an SH3/SH2 binding partner for the nonreceptor tyrosine kinase, Src. Subsequent data have demonstrated that AFAP-110 can interact with other Src family members. AFAP-110 contains additional protein binding modules including two pleckstrin homology domains, a leucine zipper motif and a target sequence for serine/threonine phosphorylation. AFAP-110 interacts with actin filaments directly via a carboxy terminal actin-binding domain. Thus AFAP-110 may function as an adaptor protein by linking Src family members and/or other signaling proteins to actin filaments. AFAP-110 also has an intrinsic capability to alter actin filament integrity that can be revealed upon conformational changes associated with phosphorylation or mutagenesis. Recent data has indicated that AFAP-110 may also serve to activate cSrc in response to this conformational change as well. Thus, AFAP-110 may function in several ways by (1) acting as an adaptor protein that links signaling molecules to actin filaments, (2) serving as a platform for the construction of larger signaling complexes, (3) serving as an activator of Src family kinases in response to cellular signals that alter its conformation and (4) directly effecting actin filament organization as an actin filament cross-linking protein. Here, we will review the structure and function of AFAP-110 as well as potential binding partners and effectors of AFAP-110's ability to alter actin filament integrity.
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Affiliation(s)
- J M Baisden
- Department Microbiology & Immunology, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown, West Virginia, WV 26506-9300 USA
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Rosé SD, Lejen T, Zhang L, Trifaró JM. Chromaffin cell F-actin disassembly and potentiation of catecholamine release in response to protein kinase C activation by phorbol esters is mediated through myristoylated alanine-rich C kinase substrate phosphorylation. J Biol Chem 2001; 276:36757-63. [PMID: 11477066 DOI: 10.1074/jbc.m006518200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The large majority of chromaffin vesicles are excluded from the plasma membrane by a cortical F-actin network. Treatment of chromaffin cells with phorbol 12-myristate 13-acetate produces disassembly of cortical F-actin, increasing the number of vesicles at release sites (Vitale, M. L., Seward, E. P., and Trifaró, J. M. (1995) Neuron 14, 353-363). Here, we provide evidence for involvement of myristoylated alanine-rich protein kinase C substrate (MARCKS), a protein kinase C substrate, in chromaffin cell secretion. MARCKS binds and cross-links F-actin, the latter is inhibited by protein kinase C-induced MARCKS phosphorylation. MARCKS was found in chromaffin cells by immunoblotting. MARCKS was also detected by immunoprecipitation. In intact or permeabilized cells MARCKS phosphorylation increased upon stimulation with 10(-7) m phorbol 12-myristate 13-acetate. This was accompanied by cortical F-actin disassembly and potentiation of secretion. MARCKS phosphorylation, cortical F-actin disassembly, and potentiation of Ca(2+)-evoked secretion were inhibited by a peptide (MARCKS phosphorylation site domain sequence (MPSD)) with amino acid sequence corresponding to MARCKS phosphorylation site. MPSD was phosphorylated in the process. A similar peptide (alanine-substituted phosphorylated site domain) with four serine residues of MPSD substituted by alanines was ineffective. These results provide the first evidence for MARCKS involvement in chromaffin cell secretion and suggest that regulation of cortical F-actin cross-linking might be involved in this process.
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Affiliation(s)
- S D Rosé
- Secretory Process Research Program, Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Spizz G, Blackshear PJ. Overexpression of the myristoylated alanine-rich C-kinase substrate inhibits cell adhesion to extracellular matrix components. J Biol Chem 2001; 276:32264-73. [PMID: 11413143 DOI: 10.1074/jbc.m103960200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mice lacking the myristoylated alanine-rich C-kinase substrate, or MARCKS protein, exhibit abnormalities consistent with a defect in the ability of neurons to migrate appropriately during forebrain development. To investigate the possibility that this phenotype could be due to disruption of normal cellular adhesion to extracellular matrix, an assay was developed in which 293 cells co-expressing MARCKS and green fluorescent protein were tested for their adhesion competence on various substrates. Fluorescence-activated cell sorting of adherent and non-adherent green fluorescent protein-expressing cells demonstrated that wild-type MARCKS inhibited adhesion of cells to fibronectin, whereas a non-myristoylated mutant did not inhibit adhesion of cells to a variety of substrates. The fibronectin competitive inhibitor RGD peptide inhibited adhesion of cells expressing all MARCKS variants equally. Cytochalasin D inhibited the adhesion of cells expressing non-myristoylated MARCKS, but did not further decrease the adhesion of cells expressing adhesion-inhibitory proteins. Confocal microscopy demonstrated the presence of inhibitory, myristoylated MARCKS at the plasma membrane, suggesting that localization at this region might be important for MARCKS to inhibit cellular adhesion. These data suggest a possible myristoylation-dependent function of MARCKS to inhibit cellular adhesion to extracellular matrix proteins, indicating a potential mechanism for the cell migration defects seen in the MARCKS-deficient mice.
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Affiliation(s)
- G Spizz
- Office of Clinical Research and Laboratory of Signal Transduction, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina, 27709, USA
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Yarmola EG, Edison AS, Lenox RH, Bubb MR. Actin filament cross-linking by MARCKS: characterization of two actin-binding sites within the phosphorylation site domain. J Biol Chem 2001; 276:22351-8. [PMID: 11294839 DOI: 10.1074/jbc.m101457200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently identified conformational changes that occur upon phosphorylation of myristoylated alanine-rich protein kinase C substrate (MARCKS) that preclude efficient cross-linking of actin filaments (Bubb, M. R., Lenox, R. H., and Edison, A. S. (1999) J. Biol. Chem. 274, 36472-36478). These results implied that the phosphorylation site domain of MARCKS has two actin-binding sites. We now present evidence for the existence of two actin-binding sites that not only mutually compete but also specifically compete with the actin-binding proteins thymosin beta(4) and actobindin to bind to actin. The effects of substitution of alanine for phenylalanine within a repeated hexapeptide segment suggest that the noncharged region of the domain contributes to binding affinity, but the binding affinity of peptides corresponding to each binding site has a steep dependence on salt concentration, consistent with presumed electrostatic interactions between these polycationic peptides and the polyanionic N terminus of actin. Phosphorylation decreases the site-specific affinity by no more than 0.7 kcal/mol, which is less than the effect of alanine substitution. However, phosphorylation has a much greater effect than alanine substitution on the loss of actin filament cross-linking activity. These results are consistent with the hypothesis that the compact structure resulting from conformational changes due to phosphorylation, in addition to modest decreases in site-specific affinity, explains the loss of cross-linking activity in phosphorylated MARCKS.
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Affiliation(s)
- E G Yarmola
- Departments of Medicine and Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, USA
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Zarling AL, Ficarro SB, White FM, Shabanowitz J, Hunt DF, Engelhard VH. Phosphorylated peptides are naturally processed and presented by major histocompatibility complex class I molecules in vivo. J Exp Med 2000; 192:1755-62. [PMID: 11120772 PMCID: PMC2213507 DOI: 10.1084/jem.192.12.1755] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Posttranslational modification of peptide antigens has been shown to alter the ability of T cells to recognize major histocompatibility complex (MHC) class I-restricted peptides. However, the existence and origin of naturally processed phosphorylated peptides presented by MHC class I molecules have not been explored. By using mass spectrometry, significant numbers of naturally processed phosphorylated peptides were detected in association with several human MHC class I molecules. In addition, CD8(+) T cells could be generated that specifically recognized a phosphorylated epitope. Thus, phosphorylated peptides are part of the repertoire of antigens available for recognition by T cells in vivo.
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Affiliation(s)
- Angela L. Zarling
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia 22908
| | - Scott B. Ficarro
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901
| | - Forest M. White
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901
| | - Donald F. Hunt
- Department of Pathology, University of Virginia, Charlottesville, Virginia 22908
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22901
| | - Victor H. Engelhard
- Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia 22908
- Department of Microbiology, University of Virginia, Charlottesville, Virginia 22908
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Yarmola EG, Somasundaram T, Boring TA, Spector I, Bubb MR. Actin-latrunculin A structure and function. Differential modulation of actin-binding protein function by latrunculin A. J Biol Chem 2000; 275:28120-7. [PMID: 10859320 DOI: 10.1074/jbc.m004253200] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Latrunculin A is used extensively as an agent to sequester monomeric actin in living cells. We hypothesize that additional activities of latrunculin A may be important for its biological activity. Our data are consistent with the formation of a 1:1 stoichiometric complex with an equilibrium dissociation constant of 0.2 to 0.4 micrometer and provide no evidence that the actin-latrunculin A complex participates in the elongation of actin filaments. Profilin and latrunculin A bind independently to actin, whereas binding of thymosin beta(4) to actin is inhibited by latrunculin A. Potential implications of this differential effect on actin-binding proteins are discussed. From a structural perspective, if latrunculin A binds to actin at a site that sterically influences binding by thymosin beta(4), then the observation that latrunculin A inhibits nucleotide exchange on actin implies an allosteric effect on the nucleotide binding cleft. Alternatively, if, as previously postulated, latrunculin A binds in the nucleotide cleft of actin, then its ability to inhibit binding by thymosin beta(4) is a surprising result that suggests that significant allosteric changes affect the thymosin beta(4) binding site. We show that latrunculin A and actin form a crystalline structure with orthorhombic space group P2(1)2(1)2(1) and diffraction to 3.10 A. A high resolution structure with optimized crystallization conditions should provide insight regarding these remarkable allosteric properties.
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Affiliation(s)
- E G Yarmola
- Department of Medicine, University of Florida, Gainesville, Florida 32610, USA
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