1
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Garg D, Fisher SA. Bioinformatic analysis of smoothelin family members supports tissue-specific functions of unique C-terminal calponin homology domains. Physiol Rep 2023; 11:e15844. [PMID: 37960982 PMCID: PMC10643981 DOI: 10.14814/phy2.15844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 10/10/2023] [Indexed: 11/15/2023] Open
Abstract
Smoothelins are cytoskeletal proteins with a single C-terminal calponin homology domain type 2 (CHD2). Little is known about the significance of variation in SMTN CHD2 domains, addressed here through analysis of public databases. A conserved 152 nt penultimate constitutive exon present in all SMTNs encodes helices II-IV of CHD2 with high identity (nt/aa 63/65%). Variable CHD2s of SMTN (helices IV-VI) are generated by alternative splicing of 165 nt exon E20. E20 and the CHD2 it encodes have high homology with the terminal constitutive exon of SMTNL1 (E8; nt/aa 72/75% identity). Unique to these CHD2 variants are a conserved extended nine amino acid C-terminal tail containing KTKK ubiquitination motifs. When E20 of SMTN is skipped (SMTN E20-), constitutive terminal E21 codes for helices IV-VI of CHD2. SMTN E21 has high identity with the terminal exon of SMTNL2 (E8; nt/aa 75/81% identity of aligned sequences) except for coding for a unique extended C-terminus (24 nt; 8aa) conserved only in mammals. SMTN isoform expression is tissue-specific: SMTNE20- and SMTNE20+ are highly expressed in SMC and non-muscle cells, respectively, while SMTNL1 + 2 are highly expressed in skeletal muscle cells. Tissue-specific expression of SMTN CHD2s with unique helices IV-VI suggest tissue-specific functions that require further study.
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Affiliation(s)
- Dhruv Garg
- Marriotts Ridge High SchoolBaltimoreMarylandUSA
| | - Steven A. Fisher
- Departments of Medicine (Cardiology) and PhysiologyUniversity of Maryland School of MedicineBaltimoreMarylandUSA
- Baltimore Veterans Affairs Medical CenterBaltimoreMarylandUSA
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2
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Nuñez E, Jones F, Muguruza-Montero A, Urrutia J, Aguado A, Malo C, Bernardo-Seisdedos G, Domene C, Millet O, Gamper N, Villarroel A. Redox regulation of K V7 channels through EF3 hand of calmodulin. eLife 2023; 12:e81961. [PMID: 36803414 PMCID: PMC9988260 DOI: 10.7554/elife.81961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Neuronal KV7 channels, important regulators of cell excitability, are among the most sensitive proteins to reactive oxygen species. The S2S3 linker of the voltage sensor was reported as a site-mediating redox modulation of the channels. Recent structural insights reveal potential interactions between this linker and the Ca2+-binding loop of the third EF-hand of calmodulin (CaM), which embraces an antiparallel fork formed by the C-terminal helices A and B, constituting the calcium responsive domain (CRD). We found that precluding Ca2+ binding to the EF3 hand, but not to EF1, EF2, or EF4 hands, abolishes oxidation-induced enhancement of KV7.4 currents. Monitoring FRET (Fluorescence Resonance Energy Transfer) between helices A and B using purified CRDs tagged with fluorescent proteins, we observed that S2S3 peptides cause a reversal of the signal in the presence of Ca2+ but have no effect in the absence of this cation or if the peptide is oxidized. The capacity of loading EF3 with Ca2+ is essential for this reversal of the FRET signal, whereas the consequences of obliterating Ca2+ binding to EF1, EF2, or EF4 are negligible. Furthermore, we show that EF3 is critical for translating Ca2+ signals to reorient the AB fork. Our data are consistent with the proposal that oxidation of cysteine residues in the S2S3 loop relieves KV7 channels from a constitutive inhibition imposed by interactions between the EF3 hand of CaM which is crucial for this signaling.
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Affiliation(s)
| | - Frederick Jones
- School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLeedsUnited Kingdom
| | | | | | | | | | | | - Carmen Domene
- Department of Chemistry, University of BathBathUnited Kingdom
- Department of Chemistry, University of OxfordOxfordUnited Kingdom
| | - Oscar Millet
- Protein Stability and Inherited Disease Laboratory, CIC bioGUNEDerioSpain
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of LeedsLeedsUnited Kingdom
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3
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Rajan S, Terman JR, Reisler E. MICAL-mediated oxidation of actin and its effects on cytoskeletal and cellular dynamics. Front Cell Dev Biol 2023; 11:1124202. [PMID: 36875759 PMCID: PMC9982024 DOI: 10.3389/fcell.2023.1124202] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 02/02/2023] [Indexed: 02/19/2023] Open
Abstract
Actin and its dynamic structural remodelings are involved in multiple cellular functions, including maintaining cell shape and integrity, cytokinesis, motility, navigation, and muscle contraction. Many actin-binding proteins regulate the cytoskeleton to facilitate these functions. Recently, actin's post-translational modifications (PTMs) and their importance to actin functions have gained increasing recognition. The MICAL family of proteins has emerged as important actin regulatory oxidation-reduction (Redox) enzymes, influencing actin's properties both in vitro and in vivo. MICALs specifically bind to actin filaments and selectively oxidize actin's methionine residues 44 and 47, which perturbs filaments' structure and leads to their disassembly. This review provides an overview of the MICALs and the impact of MICAL-mediated oxidation on actin's properties, including its assembly and disassembly, effects on other actin-binding proteins, and on cells and tissue systems.
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Affiliation(s)
- Sudeepa Rajan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jonathan R. Terman
- Departments of Neuroscience and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, United States
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
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4
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Rivière T, Bader A, Pogoda K, Walzog B, Maier-Begandt D. Structure and Emerging Functions of LRCH Proteins in Leukocyte Biology. Front Cell Dev Biol 2020; 8:584134. [PMID: 33072765 PMCID: PMC7536344 DOI: 10.3389/fcell.2020.584134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/01/2020] [Indexed: 01/10/2023] Open
Abstract
Actin-dependent leukocyte trafficking and activation are critical for immune surveillance under steady state conditions and during disease states. Proper immune surveillance is of utmost importance in mammalian homeostasis and it ensures the defense against pathogen intruders, but it also guarantees tissue integrity through the continuous removal of dying cells or the elimination of tumor cells. On the cellular level, these processes depend on the precise reorganization of the actin cytoskeleton orchestrating, e.g., cell polarization, migration, and vesicular dynamics in leukocytes. The fine-tuning of the actin cytoskeleton is achieved by a multiplicity of actin-binding proteins inducing, e.g., the organization of the actin cytoskeleton or linking the cytoskeleton to membranes and their receptors. More than a decade ago, the family of leucine-rich repeat (LRR) and calponin homology (CH) domain-containing (LRCH) proteins has been identified as cytoskeletal regulators. The LRR domains are important for protein-protein interactions and the CH domains mediate actin binding. LRR and CH domains are frequently found in many proteins, but strikingly the simultaneous expression of both domains in one protein only occurs in the LRCH protein family. To date, one LRCH protein has been described in drosophila and four LRCH proteins have been identified in the murine and the human system. The function of LRCH proteins is still under investigation. Recently, LRCH proteins have emerged as novel players in leukocyte function. In this review, we summarize our current understanding of LRCH proteins with a special emphasis on their function in leukocyte biology.
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Affiliation(s)
- Thibaud Rivière
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians-Universität München, Munich, Germany.,Walter Brendel Center of Experimental Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Almke Bader
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians-Universität München, Munich, Germany.,Walter Brendel Center of Experimental Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Kristin Pogoda
- Department of Physiology, Medical Faculty, Augsburg University, Augsburg, Germany
| | - Barbara Walzog
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians-Universität München, Munich, Germany.,Walter Brendel Center of Experimental Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Daniela Maier-Begandt
- Institute of Cardiovascular Physiology and Pathophysiology, Biomedical Center, Ludwig-Maximilians-Universität München, Munich, Germany.,Walter Brendel Center of Experimental Medicine, University Hospital, Ludwig-Maximilians-Universität München, Munich, Germany
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5
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Yin LM, Schnoor M, Jun CD. Structural Characteristics, Binding Partners and Related Diseases of the Calponin Homology (CH) Domain. Front Cell Dev Biol 2020; 8:342. [PMID: 32478077 PMCID: PMC7240100 DOI: 10.3389/fcell.2020.00342] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/20/2020] [Indexed: 01/01/2023] Open
Abstract
The calponin homology (CH) domain is one of the most common modules in various actin-binding proteins and is characterized by an α-helical fold. The CH domain plays important regulatory roles in both cytoskeletal dynamics and signaling. The CH domain is required for stability and organization of the actin cytoskeleton, calcium mobilization and activation of downstream pathways. The CH domain has recently garnered increased attention due to its importance in the onset of different diseases, such as cancers and asthma. However, many roles of the CH domain in various protein functions and corresponding diseases are still unclear. Here, we review current knowledge about the structural features, interactome and related diseases of the CH domain.
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Affiliation(s)
- Lei-Miao Yin
- Laboratory of Molecular Biology, Shanghai Research Institute of Acupuncture and Meridian, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Michael Schnoor
- Molecular Biomedicine, Center for Investigation and Advanced Studies of the National Polytechnic Institute (Cinvestav), Mexico City, Mexico
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea
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6
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Murali M, MacDonald JA. Smoothelins and the Control of Muscle Contractility. ADVANCES IN PHARMACOLOGY 2018; 81:39-78. [DOI: 10.1016/bs.apha.2017.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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7
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Chyan CL, Irene D, Lin SM. The Recognition of Calmodulin to the Target Sequence of Calcineurin-A Novel Binding Mode. Molecules 2017; 22:E1584. [PMID: 28934144 PMCID: PMC6151454 DOI: 10.3390/molecules22101584] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 11/22/2022] Open
Abstract
Calcineurin (CaN) is a Ca2+/calmodulin-dependent Ser/Thr protein phosphatase, which plays essential roles in many cellular and developmental processes. CaN comprises two subunits, a catalytic subunit (CaN-A, 60 kDa) and a regulatory subunit (CaN-B, 19 kDa). CaN-A tightly binds to CaN-B in the presence of minimal levels of Ca2+, but the enzyme is inactive until activated by CaM. Upon binding to CaM, CaN then undergoes a conformational rearrangement, the auto inhibitory domain is displaced and thus allows for full activity. In order to elucidate the regulatory role of CaM in the activation processes of CaN, we used NMR spectroscopy to determine the structure of the complex of CaM and the target peptide of CaN (CaNp). The CaM/CaNp complex shows a compact ellipsoidal shape with 8 α-helices of CaM wrapping around the CaNp helix. The RMSD of backbone and heavy atoms of twenty lowest energy structures of CaM/CaNp complex are 0.66 and 1.14 Å, respectively. The structure of CaM/CaNp complex can be classified as a novel binding mode family 1-18 with major anchor residues Ile396 and Leu413 to allocate the largest space between two domains of CaM. The relative orientation of CaNp to CaM is similar to the CaMKK peptide in the 1-16 binding mode with N- and C-terminal hydrophobic anchors of target sequence engulfed in the hydrophobic pockets of the N- and C-domain of CaM, respectively. In the light of the structural model of CaM/CaNp complex reported here, we provide new insight in the activation processes of CaN by CaM. We propose that the hydrophobic interactions between the Ca2+-saturated C-domain and C-terminal half of the target sequence provide driving forces for the initial recognition. Subsequent folding in the target sequence and structural readjustments in CaM enhance the formation of the complex and affinity to calcium. The electrostatic repulsion between CaM/CaNp complex and AID may result in the displacement of AID from active site for full activity.
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Affiliation(s)
- Chia-Lin Chyan
- Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan.
| | - Deli Irene
- Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan.
| | - Sin-Mao Lin
- Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan.
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8
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Ulke-Lemée A, Sun DH, Ishida H, Vogel HJ, MacDonald JA. Binding of smoothelin-like 1 to tropomyosin and calmodulin is mutually exclusive and regulated by phosphorylation. BMC BIOCHEMISTRY 2017; 18:5. [PMID: 28320308 PMCID: PMC5359911 DOI: 10.1186/s12858-017-0080-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 03/15/2017] [Indexed: 12/11/2022]
Abstract
Background The smoothelin-like 1 protein (SMTNL1) can associate with tropomyosin (Tpm) and calmodulin (CaM), two proteins essential to the smooth muscle contractile process. SMTNL1 is phosphorylated at Ser301 by protein kinase A during calcium desensitization in smooth muscle, yet the effect of SMTNL1 phosphorylation on Tpm- and CaM-binding has yet to be investigated. Results Using pull down studies with Tpm-Sepharose and CaM-Sepharose, we examined the interplay between Tpm binding, CaM binding, phosphorylation of SMTNL1 and calcium concentration. Phosphorylation greatly enhanced the ability of SMTNL1 to associate with Tpm in vitro; surface plasmon resonance yielded a 10-fold enhancement in KD value with phosphorylation. The effect on CaM binding is more complex and varies with the availability of calcium. Conclusions Combining both CaM and Tpm with SMTNL1 shows that the binding to both is mutually exclusive. Electronic supplementary material The online version of this article (doi:10.1186/s12858-017-0080-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Annegret Ulke-Lemée
- Department of Biochemistry & Molecular Biology, University of Calgary, Cumming School of Medicine, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - David Hao Sun
- Department of Biochemistry & Molecular Biology, University of Calgary, Cumming School of Medicine, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Hiroaki Ishida
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1 N4, Canada
| | - Hans J Vogel
- Biochemistry Research Group, Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1 N4, Canada
| | - Justin A MacDonald
- Department of Biochemistry & Molecular Biology, University of Calgary, Cumming School of Medicine, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
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9
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The Calcium-Dependent Switch Helix of L-Plastin Regulates Actin Bundling. Sci Rep 2017; 7:40662. [PMID: 28145401 PMCID: PMC5286426 DOI: 10.1038/srep40662] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/09/2016] [Indexed: 01/14/2023] Open
Abstract
L-plastin is a calcium-regulated actin-bundling protein that is expressed in cells of hematopoietic origin and in most metastatic cancer cells. These cell types are mobile and require the constant remodeling of their actin cytoskeleton, where L-plastin bundles filamentous actin. The calcium-dependent regulation of the actin-bundling activity of L-plastin is not well understood. We have used NMR spectroscopy to determine the solution structure of the EF-hand calcium-sensor headpiece domain. Unexpectedly, this domain does not bind directly to the four CH-domains of L-plastin. A novel switch helix is present immediately after the calcium-binding region and it binds tightly to the EF-hand motifs in the presence of calcium. We demonstrate that this switch helix plays a major role during actin-bundling. Moreover a peptide that competitively inhibits the association between the EF-hand motifs and the switch helix was shown to deregulate the actin-bundling activity of L-plastin. Overall, these findings may help to develop new drugs that target the L-plastin headpiece and interfere in the metastatic activity of cancer cells.
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10
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Ulke‐Lemée A, Turner SR, MacDonald JA. In situ Analysis of Smoothelin‐like 1 and Calmodulin Interactions in Smooth Muscle Cells by Proximity Ligation. J Cell Biochem 2015; 116:2667-75. [DOI: 10.1002/jcb.25215] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 04/22/2015] [Indexed: 01/20/2023]
Affiliation(s)
- Annegret Ulke‐Lemée
- Department of Biochemistry and Molecular BiologyCumming School of MedicineUniversity of CalgaryCalgaryAlbertaT2N 4Z6Canada
| | - Sara R. Turner
- Department of Biochemistry and Molecular BiologyCumming School of MedicineUniversity of CalgaryCalgaryAlbertaT2N 4Z6Canada
| | - Justin A. MacDonald
- Department of Biochemistry and Molecular BiologyCumming School of MedicineUniversity of CalgaryCalgaryAlbertaT2N 4Z6Canada
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11
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Two domains of the smoothelin-like 1 protein bind apo- and calcium–calmodulin independently. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1580-90. [DOI: 10.1016/j.bbapap.2014.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 05/14/2014] [Accepted: 05/24/2014] [Indexed: 12/24/2022]
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12
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Turner SR, MacDonald JA. Novel Contributions of the Smoothelin-like 1 Protein in Vascular Smooth Muscle Contraction and its Potential Involvement in Myogenic Tone. Microcirculation 2014; 21:249-58. [DOI: 10.1111/micc.12108] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 11/04/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Sara R. Turner
- The Smooth Muscle Research Group at the Libin Cardiovascular Institute of Alberta; Department of Biochemistry & Molecular Biology; University of Calgary; Calgary Alberta Canada
| | - Justin A. MacDonald
- The Smooth Muscle Research Group at the Libin Cardiovascular Institute of Alberta; Department of Biochemistry & Molecular Biology; University of Calgary; Calgary Alberta Canada
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Andrews WJ, Bradley CA, Hamilton E, Daly C, Mallon T, Timson DJ. A calcium-dependent interaction between calmodulin and the calponin homology domain of human IQGAP1. Mol Cell Biochem 2012; 371:217-23. [PMID: 22944912 DOI: 10.1007/s11010-012-1438-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/25/2012] [Indexed: 01/01/2023]
Abstract
IQGAPs are cytoskeletal scaffolding proteins which collect information from a variety of signalling pathways and pass it on to the microfilaments and microtubules. There is a well-characterised interaction between IQGAP and calmodulin through a series of IQ-motifs towards the middle of the primary sequence. However, it has been shown previously that the calponin homology domain (CHD), located at the N-terminus of the protein, can also interact weakly with calmodulin. Using a recombinant fragment of human IQGAP1 which encompasses the CHD, we have demonstrated that the CHD undergoes a calcium ion-dependent interaction with calmodulin. The CHD can also displace the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulphonate from calcium-calmodulin, suggesting that the interaction involves non-polar residues on the surface of calmodulin. Molecular modelling identified a possible site on the CHD for calmodulin interaction. The physiological significance of this interaction remains to be discovered.
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Affiliation(s)
- William J Andrews
- School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
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14
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Weininger U, Liu Z, McIntyre DD, Vogel HJ, Akke M. Specific 12CβD(2)12CγD(2)S13CεHD(2) isotopomer labeling of methionine to characterize protein dynamics by 1H and 13C NMR relaxation dispersion. J Am Chem Soc 2012; 134:18562-5. [PMID: 23106551 PMCID: PMC3497853 DOI: 10.1021/ja309294u] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
Protein dynamics on the micro- to millisecond time scale
is increasingly
found to be critical for biological function, as demonstrated by numerous
NMR relaxation dispersion studies. Methyl groups are excellent probes
of protein interactions and dynamics because of their favorable NMR
relaxation properties, which lead to sharp signals in the 1H and 13C NMR spectra. Out of the six different methyl-bearing
amino acid residue types in proteins, methionine plays a special role
because of its extensive side-chain flexibility and the high polarizability
of the sulfur atom. Methionine is over-represented in many protein–protein
recognition sites, making the methyl group of this residue type an
important probe of the relationships among dynamics, interactions,
and biological function. Here we present a straightforward method
to label methionine residues with specific 13CHD2 methyl isotopomers against a deuterated background. The resulting
protein samples yield NMR spectra with improved sensitivity due to
the essentially 100% population of the desired 13CHD2 methyl isotopomer, which is ideal for 1H and 13C spin relaxation experiments to investigate protein dynamics
in general and conformational exchange in particular. We demonstrate
the approach by measuring 1H and 13C CPMG relaxation
dispersion for the nine methionines in calcium-free calmodulin (apo-CaM).
The results show that the C-terminal domain, but not the N-terminal
domain, of apo-CaM undergoes fast exchange between the ground state
and a high-energy state. Since target proteins are known to bind specifically
to the C-terminal domain of apo-CaM, we speculate that the high-energy
state might be involved in target binding through conformational selection.
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Affiliation(s)
- Ulrich Weininger
- Department of Biophysical Chemistry, Center for Molecular Protein Science, Lund University, Sweden
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15
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Irene D, Huang JW, Chung TY, Li FY, Tzen JTC, Lin TH, Chyan CL. Binding orientation and specificity of calmodulin to rat olfactory cyclic nucleotide-gated ion channel. J Biomol Struct Dyn 2012; 31:414-25. [PMID: 22877078 DOI: 10.1080/07391102.2012.703069] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Calmodulin (CaM), the primary intracellular Ca(2+) receptor, regulates a large number of key enzymes and controls a wide spectrum of important biological responses. Recognition between CaM and its target sequence in rat olfactory cyclic nucleotide-gated ion channel (OLFp) was investigated by circular dichroism (CD), fluorescence, and NMR spectroscopy. Fluorescence data showed the OLFp tightly bound to CaM with a dissociation constant of 12 nM in a 1:1 stoichiometry. Far-UV CD data showed that approximately 60% of OLFp residues formed α-helical structures when associated with CaM. NMR data showed that most of the (15)N-(1)H HSQC cross-peaks of the (15)N-labeled CaM not only shifted but also split into two sets of peaks upon association with the OLFp. Our data indicated that the two distinct CaM/OLFp complexes existed simultaneously with stable structures that were not interexchangeable within the NMR time scale. In light of the palindromic sequence of OLFp (FQRIVRLVGVIRDW) for CaM targeting, we proposed that the helical OLFp with C2 symmetry may bind to CaM in two orientations. This hypothesis is supported by the observation that only one set of (15)N-(1)H HSQC cross-peaks of the (15)N-labeled CaM was detected upon association with OLFp-M13 chimeric peptide (OLFMp), a mutated OLFp lacking the palindromic feature. The binding specificity of OLFMp to CaM was restored when the palindromic feature was destroyed. Binding modes of CaM/OLFp and CaM/OLFMp simulated by molecular docking were in accord with their distinct patterns observed in HSQC spectra. Our studies suggest that the palindromic residues in OLFp are crucial for the orientation-specific recognition by CaM.
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Affiliation(s)
- Deli Irene
- Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan, ROC
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16
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MacDonald JA, Ishida H, Butler EI, Ulke-Lemée A, Chappellaz M, Tulk SE, Chik JK, Vogel HJ. Intrinsically disordered N-terminus of calponin homology-associated smooth muscle protein (CHASM) interacts with the calponin homology domain to enable tropomyosin binding. Biochemistry 2012; 51:2694-705. [PMID: 22424482 DOI: 10.1021/bi2019018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The calponin homology-associated smooth muscle (CHASM) protein plays an important adaptive role in smooth and skeletal muscle contraction. CHASM is associated with increased muscle contractility and can be localized to the contractile thin filament via its binding interaction with tropomyosin. We sought to define the structural basis for the interaction of CHASM with smooth muscle tropomyosin as a first step to understanding the contribution of CHASM to the contractile capacity of smooth muscle. Herein, we provide a structure-based model for the tropomyosin-binding domain of CHASM using a combination of hydrogen/deuterium exchange mass spectrometry (HDX-MS) and NMR analyses. Our studies provide evidence that a portion of the N-terminal intrinsically disordered region forms intramolecular contacts with the globular C-terminal calponin homology (CH) domain. Ultimately, cooperativeness between these structurally dissimilar regions is required for CHASM binding to smooth muscle tropomyosin. Furthermore, it appears that the type-2 CH domain of CHASM is required for tropomyosin binding and presents a novel function for this protein domain.
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Affiliation(s)
- Justin A MacDonald
- Department of Biochemistry & Molecular Biology, University of Calgary, Calgary, Alberta, Canada T2N 4Z6.
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17
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Bodoor K, Lontay B, Safi R, Weitzel DH, Loiselle D, Wei Z, Lengyel S, McDonnell DP, Haystead TA. Smoothelin-like 1 protein is a bifunctional regulator of the progesterone receptor during pregnancy. J Biol Chem 2011; 286:31839-51. [PMID: 21771785 DOI: 10.1074/jbc.m111.270397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
During pregnancy, uterine smooth muscle (USM) coordinately adapts its contractile phenotype in order to accommodate the developing fetus and then prepare for delivery. Herein we show that SMTNL1 plays a major role in pregnancy to promote adaptive responses in USM and that this process is specifically mediated through interactions of SMTNL1 with the steroid hormone receptor PR-B. In vitro and in vivo SMTNL1 selectively binds PR and not other steroid hormone receptors. The physiological relationship between the two proteins was also established in global gene expression and transcriptional reporter studies in pregnant smtnl1(-/-) mice and by RNA interference in progesterone-sensitive cell lines. We show that the contraction-associated and progestin-sensitive genes (oxytocin receptor, connexin 43, and cyclooxygenase-2) and prolactins are down-regulated in pregnant smtnl1(-/-) mice. We suggest that SMTNL1 is a bifunctional co-regulator of PR-B signaling and thus provides a molecular mechanism whereby PR-B is targeted to alter gene expression patterns within USM cells to coordinately promote alterations in USM function during pregnancy.
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Affiliation(s)
- Khaldon Bodoor
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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18
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Ulke-Lemée A, Turner SR, Mughal SH, Borman MA, Winkfein RJ, MacDonald JA. Mapping and functional characterization of the murine smoothelin-like 1 promoter. BMC Mol Biol 2011; 12:10. [PMID: 21352594 PMCID: PMC3050715 DOI: 10.1186/1471-2199-12-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 02/27/2011] [Indexed: 11/23/2022] Open
Abstract
Background Smoothelin-like 1 (SMTNL1, also known as CHASM) plays a role in promoting relaxation as well as adaptive responses to exercise, pregnancy and sexual development in smooth and skeletal muscle. Investigations of Smtnl1 transcriptional regulation are still lacking. Thus, in this study, we identify and characterize key regulatory elements of the mouse Smtnl1 gene. Results We mapped the key regulatory elements of the Smtnl1 promoter region: the transcriptional start site (TSS) lays -44 bp from the translational start codon and a TATA-box motif at -75 bp was conserved amongst all mammalian Smtnl1 promoters investigated. The Smtnl1 proximal promoter enhances expression up to 8-fold in smooth muscle cells and a second activating region lays 500 bp further upstream. Two repressing motifs were present (-118 to -218 bp and -1637 to -1869 bp). The proximal promoter is highly conserved in mammals and contains a mirror repeat sequence. In silico analysis suggests many transcription factors (notably MyoD) could potentially bind within the Smtnl1 proximal promoter sequence. Conclusion Smtnl1 transcript was identified in all smooth muscle tissues examined to date, albeit at much lower levels than found in skeletal muscle. It is unlikely that multiple SMTNL1 isoforms exist since a single Smtnl1 transcription start site was identified in both skeletal and intestinal smooth muscle. Promoter studies suggest restrictive control of Smtnl1 expression in non-muscle cells.
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Affiliation(s)
- Annegret Ulke-Lemée
- Smooth Muscle Research Group, Department of Biochemistry & Molecular Biology, University of Calgary, Alberta, Canada
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19
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Isozumi N, Iida Y, Nakatomi A, Nemoto N, Yazawa M, Ohki S. Conformation of the calmodulin-binding domain of metabotropic glutamate receptor subtype 7 and its interaction with calmodulin. J Biochem 2011; 149:463-74. [PMID: 21258069 DOI: 10.1093/jb/mvr006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Calmodulin (CaM), a Ca(2+)-binding protein, is a well-known regulator of various cellular functions. One of the targets of CaM is metabotropic glutamate receptor 7 (mGluR7), which serves as a low-pass filter for glutamate in the pre-synaptic terminal to regulate neurotransmission. Surface plasmon resonance (SPR), circular dichroism (CD) spectroscopy and nuclear magnetic spectroscopy (NMR) were performed to study the structure of the peptides corresponding to the CaM-binding domain of mGluR7 and their interaction with CaM. Unlike well-known CaM-binding peptides, mGluR7 has a random coil structure even in the presence of trifluoroethanol. Moreover, NMR data suggested that the complex between Ca(2+)/CaM and the mGluR7 peptide has multiple conformations. The mGluR7 peptide has been found to interact with CaM even in the absence of Ca(2+), and the binding is directed toward the C-domain of apo-CaM rather than the N-domain. We propose a possible mechanism for the activation of mGluR7 by CaM. A pre-binding occurs between apo-CaM and mGluR7 in the resting state of cells. Then, the Ca(2+)/CaM-mGluR7 complex is formed once Ca(2+) influx occurs. The weak interaction at lower Ca(2+) concentrations is likely to bind CaM to mGluR7 for the fast complex formation in response to the elevation of Ca(2+) concentration.
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Affiliation(s)
- Noriyoshi Isozumi
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
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20
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Ulke-Lemée A, Ishida H, Borman MA, Valderrama A, Vogel HJ, MacDonald JA. Tropomyosin-binding properties of the CHASM protein are dependent upon its calponin homology domain. FEBS Lett 2010; 584:3311-6. [PMID: 20627103 DOI: 10.1016/j.febslet.2010.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 07/06/2010] [Accepted: 07/06/2010] [Indexed: 10/19/2022]
Abstract
The calponin homology-associated smooth muscle protein (CHASM) can modulate muscle contractility, and its biological action may involve an interaction with the contractile filament. In this study, we demonstrate an interaction between CHASM and tropomyosin. Deletion constructs of CHASM were generated, and pull-down assays revealed a minimal deletion construct that could bind tropomyosin. Removal of the calponin homology (CH) domain or expression of the CH domain alone did not enable binding. The interaction was characterized by microcalorimetry with a dissociation constant of 2.0x10(-6) M. Confocal fluorescence microscopy also showed green fluorescent protein (GFP)-CHASM localization to filamentous structures within smooth muscle cells, and this targeting was dependent upon the CH domain.
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Affiliation(s)
- Annegret Ulke-Lemée
- Department of Biochemistry and Molecular Biology, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta, Canada T2N 4Z6
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21
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Lontay B, Bodoor K, Weitzel DH, Loiselle D, Fortner C, Lengyel S, Zheng D, Devente J, Hickner R, Haystead TAJ. Smoothelin-like 1 protein regulates myosin phosphatase-targeting subunit 1 expression during sexual development and pregnancy. J Biol Chem 2010; 285:29357-66. [PMID: 20634291 DOI: 10.1074/jbc.m110.143966] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pregnancy coordinately alters the contractile properties of both vascular and uterine smooth muscles reducing systemic blood pressure and maintaining uterine relaxation. The precise molecular mechanisms underlying these pregnancy-induced adaptations have yet to be fully defined but are likely to involve changes in the expression of proteins regulating myosin phosphorylation. Here we show that smoothelin like protein 1 (SMTNL1) is a key factor governing sexual development and pregnancy induced adaptations in smooth and striated muscle. A primary target gene of SMTNL1 in these muscles is myosin phosphatase-targeting subunit 1 (MYPT1). Deletion of SMTNL1 increases expression of MYPT1 30-40-fold in neonates and during development expression of both SMTNL1 and MYPT1 increases over 20-fold. Pregnancy also regulates SMTNL1 and MYPT1 expression, and deletion SMTNL1 greatly exaggerates expression of MYPT1 in vascular smooth muscle, producing a profound reduction in force development in response to phenylephrine as well as sensitizing the muscle to acetylcholine. We also show that MYPT1 is expressed in Type2a muscle fibers in mice and humans and its expression is regulated during pregnancy, suggesting unrecognized roles in mediating skeletal muscle plasticity in both species. Our findings define a new conserved pathway in which sexual development and pregnancy mediate smooth and striated muscle adaptations through SMTNL1 and MYPT1.
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Affiliation(s)
- Beata Lontay
- Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710, USA
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22
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Survey of the year 2008: applications of isothermal titration calorimetry. J Mol Recognit 2010; 23:395-413. [DOI: 10.1002/jmr.1025] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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23
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Borman MA, Freed TA, Haystead TAJ, MacDonald JA. The role of the calponin homology domain of smoothelin-like 1 (SMTNL1) in myosin phosphatase inhibition and smooth muscle contraction. Mol Cell Biochem 2009; 327:93-100. [PMID: 19219534 PMCID: PMC2846773 DOI: 10.1007/s11010-009-0047-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2008] [Accepted: 01/28/2009] [Indexed: 11/29/2022]
Abstract
In this study, we provide further insight into the contribution of the smoothelin-like 1 (SMTNL1) calponin homology (CH)-domain on myosin light chain phosphatase (SMPP-1M) activity and smooth muscle contraction. SMTNL1 protein was shown to have inhibitory effects on SMPP-1M activity but not on myosin light chain kinase (MLCK) activity. Treatment of beta-escin permeabilized rabbit, ileal smooth muscle with SMTNL1 had no effect on the time required to reach half-maximal force (t(1/2)) during stimulation with pCa6.3 solution. The addition of recombinant SMTNL1 protein to permeabilized, smooth muscle strips caused a significant decrease in contractile force. While the calponin homology (CH)-domain was essential for maximal SMTNL1-associated relaxation, it alone did not cause significant changes in force. SMTNL1 was poorly dephosphorylated by PP-1C in the presence of the myosin targeting subunit (MYPT1), suggesting that phosphorylated SMTNL1 does not possess "substrate trapping" properties. Moreover, while full-length SMTNL1 could suppress SMPP-1M activity toward LC(20) in vitro, truncated SMTNL1 lacking the CH-domain was ineffective. In summary, our findings suggest an important role for the CH-domain in mediating the effects of SMTNL1 on smooth muscle contraction.
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Affiliation(s)
- Meredith A. Borman
- Faculty of Medicine, Department of Biochemistry & Molecular Biology, University of Calgary, 3330 Hospital Drive N.W., Calgary, AB T2N 4N1, Canada
| | - Tiffany A. Freed
- Department of Pharmacology and Cancer Biology, Duke, University Medical Center, Durham, NC 27710, USA
| | - Timothy A. J. Haystead
- Department of Pharmacology and Cancer Biology, Duke, University Medical Center, Durham, NC 27710, USA
| | - Justin A. MacDonald
- Faculty of Medicine, Department of Biochemistry & Molecular Biology, University of Calgary, 3330 Hospital Drive N.W., Calgary, AB T2N 4N1, Canada
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Yamniuk AP, Ishida H, Lippert D, Vogel HJ. Thermodynamic effects of noncoded and coded methionine substitutions in calmodulin. Biophys J 2009; 96:1495-507. [PMID: 19217866 PMCID: PMC2717255 DOI: 10.1016/j.bpj.2008.10.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Accepted: 10/28/2008] [Indexed: 11/16/2022] Open
Abstract
The methionine residues in the calcium (Ca2+) regulatory protein calmodulin (CaM) are structurally and functionally important. They are buried within the N- and C-domains of apo-CaM but become solvent-exposed in Ca2+-CaM, where they interact with numerous target proteins. Previous structural studies have shown that methionine substitutions to the noncoded amino acids selenomethionine, ethionine, or norleucine, or mutation to leucine do not impact the main chain structure of CaM. Here we used differential scanning calorimetry to show that these substitutions enhance the stability of both domains, with the largest increase in melting temperature (19-26 degrees C) achieved with leucine or norleucine in the apo-C-domain. Nuclear magnetic resonance spectroscopy experiments also revealed the loss of a slow conformational exchange process in the Leu-substituted apo-C-domain. In addition, isothermal titration calorimetry experiments revealed considerable changes in the enthalpy and entropy of target binding to apo-CaM and Ca2+-CaM, but the free energy of binding was largely unaffected due to enthalpy-entropy compensation. Collectively, these results demonstrate that noncoded and coded methionine substitutions can be accommodated in CaM because of the structural plasticity of the protein. However, adjustments in side-chain packing and dynamics lead to significant differences in protein stability and the thermodynamics of target binding.
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Affiliation(s)
- Aaron P. Yamniuk
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Hiroaki Ishida
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Dustin Lippert
- Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Hans J. Vogel
- Structural Biology Research Group, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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25
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Chen HH, Murchland I, Booker GW. Assignment of the 1H, 13C and 15N resonances of the calponin homology-2 domain of alpha-actinin-4. BIOMOLECULAR NMR ASSIGNMENTS 2008; 2:195-7. [PMID: 19636903 DOI: 10.1007/s12104-008-9119-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/08/2008] [Indexed: 05/28/2023]
Abstract
We report the assignment of the 110 amino acid second calponin homology domain of human alpha-actinin-4. The two calponin homology domains of alpha-actinin combine to regulate F-actin binding.
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Affiliation(s)
- Huang-Hui Chen
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, SA, 5005, Australia
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