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Moretti E, Noto D, Corsaro R, Collodel G. Focus on centrin in normal and altered human spermatozoa. Syst Biol Reprod Med 2023; 69:175-187. [PMID: 36892570 DOI: 10.1080/19396368.2023.2181115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
This review provides details on the role of centrin in human spermatozoa and in various forms of male infertility. Centrin is a calcium (Ca2+)-binding phosphoprotein that is located in the centrioles - which are typical structures of the sperm connecting piece and play a key role in centrosome dynamics during sperm morphogenesis - as well as in zygotes and early embryos during spindle assembly. In humans, three different centrin genes encoding three isoforms have been discovered. Centrin 1, the only one expressed in spermatozoa, seems to be lost inside the oocyte after fertilization. The sperm connecting piece is characterized by the presence of numerous proteins including centrin, that deserves particular attention because, in humans, it is enriched during maturation of the centrioles. In normal sperm, centrin 1 is visible as two distinct spots in the head-tail junction; however, in some defective spermatozoa, centrin 1 distribution is altered. Centrin has been studied in humans and animal models. Its mutations may lead to several structural alterations, such as serious defects in the connective piece and, subsequently, fertilization failure or incomplete embryonic development. However, the effects of these abnormalities on male fertility have not been fully studied. Because the presence and the function of centrin in the sperm connecting piece appears important for reproductive success, additional studies are needed to bring medical benefits in resolving some cases of idiopathic infertility.
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Affiliation(s)
- Elena Moretti
- Department Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Daria Noto
- Department Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Roberta Corsaro
- Department Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Giulia Collodel
- Department Molecular and Developmental Medicine, University of Siena, Siena, Italy
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Conformational Plasticity of Centrin 1 from Toxoplasma gondii in Binding to the Centrosomal Protein SFI1. Biomolecules 2022; 12:biom12081115. [PMID: 36009009 PMCID: PMC9406199 DOI: 10.3390/biom12081115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 12/01/2022] Open
Abstract
Centrins are calcium (Ca2+)-binding proteins that are involved in many cellular functions including centrosome regulation. A known cellular target of centrins is SFI1, a large centrosomal protein containing multiple repeats that represent centrin-binding motifs. Recently, a protein homologous to yeast and mammalian SFI1, denominated TgSFI1, which shares SFI1-repeat organization, was shown to colocalize at centrosomes with centrin 1 from Toxoplasma gondii (TgCEN1). However, the molecular details of the interaction between TgCEN1 and TgSFI1 remain largely unknown. Herein, combining different biophysical methods, including isothermal titration calorimetry, nuclear magnetic resonance, circular dichroism, and fluorescence spectroscopy, we determined the binding properties of TgCEN1 and its individual N- and C-terminal domains to synthetic peptides derived from distinct repeats of TgSFI1. Overall, our data indicate that the repeats in TgSFI1 constitute binding sites for TgCEN1, but the binding modes of TgCEN1 to the repeats differ appreciably in terms of binding affinity, Ca2+ sensitivity, and lobe-specific interaction. These results suggest that TgCEN1 displays remarkable conformational plasticity, allowing for the distinct repeats in TgSFI1 to possess precise modes of TgCEN1 binding and regulation during Ca2+ sensing, which appears to be crucial for the dynamic association of TgCEN1 with TgSFI1 in the centrosome architecture.
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Yang J, Zhao Y, Yang B. Phosphorylation promotes the endonuclease-like activity of human centrin 2. RSC Adv 2022; 12:21892-21903. [PMID: 36043059 PMCID: PMC9361469 DOI: 10.1039/d2ra03402f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/25/2022] [Indexed: 11/29/2022] Open
Abstract
Centrin is a member of the EF-hand superfamily of calcium-binding proteins, which is involved in the nucleotide excision repair (NER). Reversible phosphorylation of centrin is an important regulatory mechanism in vivo and is closely related to many physiological processes. To explore the possible role of centrin in NER, the endonuclease-like activity of human centrin 2 (HsCen2) regulated by phosphorylation in the absence or presence of Tb3+ was investigated by spectroscopy techniques, gel electrophoresis, and molecular docking simulation in 10 mM Hepes, pH 7.4. The results showed that phosphorylation weakened the binding of Tb3+ to HsCen2 and enhanced the binding of DNA to HsCen2. Phosphorylation improves the endonuclease-like activity of HsCen2. In addition, Tb3+ is favorable for DNA binding and endonuclease-like activity of HsCen2 before and after phosphorylation. These results provide clear insights into the effects of phosphorylation on the properties of HsCen2 and offer important clues for further exploration of how phosphorylation affects protein-driven functions. Phosphorylation weakened the binding of Tb3+ to HsCen2, enhanced the binding of DNA to HsCen2; and improves the endonuclease-like activity of HsCen2; Additionally, the endonuclease-like activity of HsCen2 or HsCen2p is regulated up by Tb3+-binding.![]()
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Affiliation(s)
- Jing Yang
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular, Shanxi University Taiyuan 030006 China +86 351 7016358
| | - Yaqin Zhao
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular, Shanxi University Taiyuan 030006 China +86 351 7016358
| | - Binsheng Yang
- Institute of Molecular Science, Key Laboratory of Chemical Biology of Molecular, Shanxi University Taiyuan 030006 China +86 351 7016358
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Novel Gene Signatures as Prognostic Biomarkers for Predicting the Recurrence of Hepatocellular Carcinoma. Cancers (Basel) 2022; 14:cancers14040865. [PMID: 35205612 PMCID: PMC8870597 DOI: 10.3390/cancers14040865] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 12/10/2022] Open
Abstract
Simple Summary A high percentage of patients who undergo surgical resection for hepatocellular carcinoma (HCC) experience recurrence. Therefore, identification of accurate molecular markers for predicting recurrence of HCC is important. We analyzed recurrence and non-recurrence HCC tissues using two public omics datasets comprising microarray and RNA-sequencing and found novel gene signatures associated with recurrent HCC. These molecules might be used to not only predict for recurrence of HCC but also act as potential prognostic indicators for patients with HCC. Abstract Hepatocellular carcinoma (HCC) has a high rate of cancer recurrence (up to 70%) in patients who undergo surgical resection. We investigated prognostic gene signatures for predicting HCC recurrence using in silico gene expression analysis. Recurrence-associated gene candidates were chosen by a comparative analysis of gene expression profiles from two independent whole-transcriptome datasets in patients with HCC who underwent surgical resection. Five promising candidate genes, CETN2, HMGA1, MPZL1, RACGAP1, and SNRPB were identified, and the expression of these genes was evaluated using quantitative reverse transcription PCR in the validation set (n = 57). The genes CETN2, HMGA1, RACGAP1, and SNRPB, but not MPZL1, were upregulated in patients with recurrent HCC. In addition, the combination of HMGA1 and MPZL1 demonstrated the best area under the curve (0.807, 95% confidence interval [CI] = 0.681–0.899) for predicting HCC recurrence. In terms of clinicopathological correlation, CETN2, MPZL1, RACGAP1, and SNRPB were upregulated in patients with microvascular invasion, and the expression of MPZL1 and SNRPB was increased in proportion to the Edmonson tumor differentiation grade. Additionally, overexpression of CETN2, HMGA1, and RACGAP1 correlated with poor overall survival (OS) and disease-free survival (DFS) in the validation set. Finally, Cox regression analysis showed that the expression of serum alpha-fetoprotein and RACGAP1 significantly affected OS, whereas platelet count, microvascular invasion, and HMGA1 expression significantly affected DFS. In conclusion, HMGA1 and RACGAP1 may be potential prognostic biomarkers for predicting the recurrence of HCC after surgical resection.
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Structural Basis for the Functional Diversity of Centrins: A Focus on Calcium Sensing Properties and Target Recognition. Int J Mol Sci 2021; 22:ijms222212173. [PMID: 34830049 PMCID: PMC8622359 DOI: 10.3390/ijms222212173] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 11/23/2022] Open
Abstract
Centrins are a family of small, EF hand-containing proteins that are found in all eukaryotes and are often complexed with centrosome-related structures. Since their discovery, centrins have attracted increasing interest due to their multiple, diverse cellular functions. Centrins are similar to calmodulin (CaM) in size, structure and domain organization, although in contrast to CaM, the majority of centrins possess at least one calcium (Ca2+) binding site that is non-functional, thus displaying large variance in Ca2+ sensing abilities that could support their functional versatility. In this review, we summarize current knowledge on centrins from both biophysical and structural perspectives with an emphasis on centrin-target interactions. In-depth analysis of the Ca2+ sensing properties of centrins and structures of centrins complexed with target proteins can provide useful insight into the mechanisms of the different functions of centrins and how these proteins contribute to the complexity of the Ca2+ signaling cascade. Moreover, it can help to better understand the functional redundancy of centrin isoforms and centrin-binding proteins.
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The interplay of self-assembly and target binding in centrin 1 from Toxoplasma gondii. Biochem J 2021; 478:2571-2587. [PMID: 34114596 PMCID: PMC8286830 DOI: 10.1042/bcj20210295] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/17/2022]
Abstract
Centrins are conserved calcium (Ca2+)-binding proteins typically associated with centrosomes that have been implicated in several biological processes. In Toxoplasma gondii, a parasite that causes toxoplasmosis, three centrin isoforms have been recognized. We have recently characterized the metal binding and structural features of isoform 1 (TgCEN1), demonstrating that it possesses properties consistent with a role as a Ca2+ sensor and displays a Ca2+-dependent tendency to self-assemble. Herein, we expanded our studies, focusing on the self-association and target binding properties of TgCEN1 by combining biophysical techniques including dynamic light scattering, isothermal titration calorimetry, nuclear magnetic resonance, circular dichroism, and fluorescence spectroscopy. We found that the self-assembly process of TgCEN1 depends on different physicochemical factors, including Ca2+ concentration, temperature, and protein concentration, and is mediated by both electrostatic and hydrophobic interactions. The process is completely abolished upon removal of the first 21-residues of the protein and is significantly reduced in the presence of a binding target peptide derived from the human XPC protein (P17-XPC). Titration of P17-XPC to the intact protein and isolated domains showed that TgCEN1 possesses two binding sites with distinct affinities and Ca2+ sensitivity; a high-affinity site in the C-lobe which may be constitutively bound to the peptide and a low-affinity site in the N-lobe which is active only upon Ca2+ stimulus. Overall, our results suggest a specific mechanism of TgCEN1 for Ca2+-modulated target binding and support a N-to-C self-assembly mode, in which the first 21-residues of one molecule likely interact with the C-lobe of the other.
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Bombardi L, Pedretti M, Conter C, Dominici P, Astegno A. Distinct Calcium Binding and Structural Properties of Two Centrin Isoforms from Toxoplasma gondii. Biomolecules 2020; 10:E1142. [PMID: 32759683 PMCID: PMC7465447 DOI: 10.3390/biom10081142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/27/2020] [Accepted: 07/31/2020] [Indexed: 11/16/2022] Open
Abstract
Centrins are calcium (Ca2+)-binding proteins that have been implicated in several regulatory functions. In the protozoan parasite Toxoplasma gondii, the causative agent of toxoplasmosis, three isoforms of centrin have been identified. While increasing information is now available that links the function of centrins with defined parasite biological processes, knowledge is still limited on the metal-binding and structural properties of these proteins. Herein, using biophysical and structural approaches, we explored the Ca2+ binding abilities and the subsequent effects of Ca2+ on the structure of a conserved (TgCEN1) and a more divergent (TgCEN2) centrin isoform from T. gondii. Our data showed that TgCEN1 and TgCEN2 possess diverse molecular features, suggesting that they play nonredundant roles in parasite physiology. TgCEN1 binds two Ca2+ ions with high/medium affinity, while TgCEN2 binds one Ca2+ with low affinity. TgCEN1 undergoes significant Ca2+-dependent conformational changes that expose hydrophobic patches, supporting a role as a Ca2+ sensor in toxoplasma. In contrast, Ca2+ binding has a subtle influence on conformational features of TgCEN2 without resulting in hydrophobic exposure, suggesting a different Ca2+ relay mode for this isoform. Furthermore, TgCEN1 displays a Ca2+-dependent ability to self-assemble, while TgCEN2 did not. We discuss our findings in the context of Ca2+ signaling in toxoplasma.
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Affiliation(s)
| | | | | | | | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy; (L.B.); (M.P.); (C.C.); (P.D.)
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8
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SAC3B is a target of CML19, the centrin 2 of Arabidopsis thaliana. Biochem J 2020; 477:173-189. [PMID: 31860002 DOI: 10.1042/bcj20190674] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/15/2023]
Abstract
Arabidopsis centrin 2, also known as calmodulin-like protein 19 (CML19), is a member of the EF-hand superfamily of calcium (Ca2+)-binding proteins. In addition to the notion that CML19 interacts with the nucleotide excision repair protein RAD4, CML19 was suggested to be a component of the transcription export complex 2 (TREX-2) by interacting with SAC3B. However, the molecular determinants of this interaction have remained largely unknown. Herein, we identified a CML19-binding site within the C-terminus of SAC3B and characterized the binding properties of the corresponding 26-residue peptide (SAC3Bp), which exhibits the hydrophobic triad centrin-binding motif in a reversed orientation (I8W4W1). Using a combination of spectroscopic and calorimetric experiments, we shed light on the SAC3Bp-CML19 complex structure in solution. We demonstrated that the peptide interacts not only with Ca2+-saturated CML19, but also with apo-CML19 to form a protein-peptide complex with a 1 : 1 stoichiometry. Both interactions involve hydrophobic and electrostatic contributions and include the burial of Trp residues of SAC3Bp. However, the peptide likely assumes different conformations upon binding to apo-CML19 or Ca2+-CML19. Importantly, the peptide dramatically increases the affinity for Ca2+ of CML19, especially of the C-lobe, suggesting that in vivo the protein would be Ca2+-saturated and bound to SAC3B even at resting Ca2+-levels. Our results, providing direct evidence that Arabidopsis SAC3B is a CML19 target and proposing that CML19 can bind to SAC3B through its C-lobe independent of a Ca2+ stimulus, support a functional role for these proteins in TREX-2 complex and mRNA export.
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9
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Calcium and phosphorylation double-regulating caltractin initiating target protein XPC function. Int J Biol Macromol 2019; 136:503-511. [DOI: 10.1016/j.ijbiomac.2019.06.095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 01/22/2023]
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10
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Shan F, Yang X, Diwu Y, Ma H, Tu X. Trypanosoma brucei centrin5 is enriched in the flagellum and interacts with other centrins in a calcium-dependent manner. FEBS Open Bio 2019; 9:1421-1431. [PMID: 31161731 PMCID: PMC6668372 DOI: 10.1002/2211-5463.12683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/24/2019] [Accepted: 05/31/2019] [Indexed: 11/21/2022] Open
Abstract
Centrin is an evolutionarily conserved EF‐hand‐containing protein, which is present in eukaryotic organisms as diverse as algae, yeast, and humans. Centrins are associated with the microtubule‐organizing center and with centrosome‐related structures, such as basal bodies in flagellar and ciliated cells, and the spindle pole body in yeast. Five centrin genes have been identified in Trypanosoma brucei (T. brucei), a protozoan parasite that causes sleeping sickness in humans and nagana in cattle in sub‐Saharan Africa. In the present study, we identified that centrin5 of T. brucei (TbCentrin5) is localized throughout the cytosol and nucleus and enriched in the flagellum. We further identified that TbCentrin5 binds Ca2+ ions with a high affinity and constructed a model of TbCentrin5 bound by Ca2+ ions. Meanwhile, we observed that TbCentrin5 interacts with TbCentrin1, TbCentrin3, and TbCentrin4 and that the interactions are Ca2+‐dependent, suggesting that TbCentrin5 is able to form different complexes with other TbCentrins to participate in relevant cellular processes. Our study provides a foundation for better understanding of the biological roles of TbCentrin5.
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Affiliation(s)
- Fangzhen Shan
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, China
| | - Xiao Yang
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, China
| | - Yating Diwu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, China
| | - Haoyu Ma
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, China
| | - Xiaoming Tu
- Hefei National Laboratory for Physical Science at Microscale and School of Life Science, University of Science and Technology of China, Hefei, China
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Roques M, Stanway RR, Rea EI, Markus R, Brady D, Holder AA, Guttery DS, Tewari R. Plasmodium centrin PbCEN-4 localizes to the putative MTOC and is dispensable for malaria parasite proliferation. Biol Open 2019; 8:bio.036822. [PMID: 30541825 PMCID: PMC6361220 DOI: 10.1242/bio.036822] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Centrins are calmodulin-like phosphoproteins present in the centrosome and play an active role in the duplication, separation and organization of centrosomal structures such as the microtubule-organizing centre (MTOC) during mitosis. They are also major components of the basal body of flagella and cilia. In Plasmodium spp., the parasite that causes malaria, mitosis is closed during asexual replication and the MTOC is embedded within the intact nuclear membrane. The MTOC has been named the centriolar plaque and is similar to the spindle pole body in yeast. In all phases of asexual replication, repeated rounds of nuclear division precede cell division. However, our knowledge of the location and function of centrins during this process is limited. Previous studies have identified four putative centrins in the human parasite Plasmodiumfalciparum. We report here the cellular localization of an alveolate-specific centrin (PbCEN-4) during the atypical cell division of asexual replicative stages, using live cell imaging with the rodent malaria parasite P. berghei as a model system. We show that this centrin forms a multi-protein complex with other centrins, but is dispensable for parasite proliferation. Summary: This study examines the localization of malaria parasite centrin PbCEN4 at the parasite MTOC during closed endomitosis and shows it to be dispensable for proliferation.
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Affiliation(s)
- Magali Roques
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Rebecca R Stanway
- Institute of Cell Biology, University of Bern, Bern 3012, Switzerland
| | - Edward I Rea
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Robert Markus
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Declan Brady
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | | | - David S Guttery
- The Leicester Cancer Research Centre, College of Life Sciences, University of Leicester, Leicester LE2 7LX, UK
| | - Rita Tewari
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
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Chlamydomonas Basal Bodies as Flagella Organizing Centers. Cells 2018; 7:cells7070079. [PMID: 30018231 PMCID: PMC6070942 DOI: 10.3390/cells7070079] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 11/17/2022] Open
Abstract
During ciliogenesis, centrioles convert to membrane-docked basal bodies, which initiate the formation of cilia/flagella and template the nine doublet microtubules of the flagellar axoneme. The discovery that many human diseases and developmental disorders result from defects in flagella has fueled a strong interest in the analysis of flagellar assembly. Here, we will review the structure, function, and development of basal bodies in the unicellular green alga Chlamydomonas reinhardtii, a widely used model for the analysis of basal bodies and flagella. Intraflagellar transport (IFT), a flagella-specific protein shuttle critical for ciliogenesis, was first described in C. reinhardtii. A focus of this review will be on the role of the basal bodies in organizing the IFT machinery.
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Villalobo A, Ishida H, Vogel HJ, Berchtold MW. Calmodulin as a protein linker and a regulator of adaptor/scaffold proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1865:507-521. [PMID: 29247668 DOI: 10.1016/j.bbamcr.2017.12.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 01/29/2023]
Abstract
Calmodulin (CaM) is a universal regulator for a huge number of proteins in all eukaryotic cells. Best known is its function as a calcium-dependent modulator of the activity of enzymes, such as protein kinases and phosphatases, as well as other signaling proteins including membrane receptors, channels and structural proteins. However, less well known is the fact that CaM can also function as a Ca2+-dependent adaptor protein, either by bridging between different domains of the same protein or by linking two identical or different target proteins together. These activities are possible due to the fact that CaM contains two independently-folded Ca2+ binding lobes that are able to interact differentially and to some degree separately with targets proteins. In addition, CaM can interact with and regulates several proteins that function exclusively as adaptors. This review provides an overview over our present knowledge concerning the structural and functional aspects of the role of CaM as an adaptor protein and as a regulator of known adaptor/scaffold proteins.
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Affiliation(s)
- Antonio Villalobo
- Department of Cancer Biology, Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, Arturo Duperier 4, E-28029 Madrid, Spain.
| | - Hiroaki Ishida
- Department of Biological Sciences, University of Calgary, 2500 University Dr. N.W., Calgary, Alberta T2N 1N4, Canada
| | - Hans J Vogel
- Department of Biological Sciences, University of Calgary, 2500 University Dr. N.W., Calgary, Alberta T2N 1N4, Canada.
| | - Martin W Berchtold
- Department of Biology, University of Copenhagen, 13 Universitetsparken, DK-2100 Copenhagen Ø, Denmark.
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La Verde V, Trande M, D'Onofrio M, Dominici P, Astegno A. Binding of calcium and target peptide to calmodulin-like protein CML19, the centrin 2 of Arabidopsis thaliana. Int J Biol Macromol 2017; 108:1289-1299. [PMID: 29129631 DOI: 10.1016/j.ijbiomac.2017.11.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 11/07/2017] [Accepted: 11/08/2017] [Indexed: 01/03/2023]
Abstract
Calmodulin-like protein 19 (CML19) is an Arabidopsis centrin that modulates nucleotide excision repair (NER) by binding to RAD4 protein, the Arabidopsis homolog of human Xeroderma pigmentosum complementation group C protein. Although the necessity of CML19 as a part of the RAD4 plant recognition complex for functional NER is known at a cellular level, little is known at a molecular level. Herein, we used a combination of biophysical and biochemical approaches to investigate the structural and ion and target-peptide binding properties of CML19. We found that CML19 possesses four Ca2+-specific binding sites, two of high affinity in the N-terminal domain and two of low affinity in the C-terminal domain. Binding of Ca2+ to CML19 increases its alpha-helix content, stabilizes the tertiary structure, and triggers a conformational change, resulting in the exposure of a hydrophobic patch instrumental for target protein recognition. Using bioinformatics tools we identified a CML19-binding site at the C-terminus of RAD4, and through in vitro binding experiments we analyzed the interaction between a 17-mer peptide representing this site and CML19. We found that the peptide shows a high affinity for CML19 in the presence of Ca2+ (stoichiometry 1:1) and the interaction primarily involves the C-terminal half of CML19.
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Affiliation(s)
- Valentina La Verde
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Matteo Trande
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Mariapina D'Onofrio
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Italy.
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Plattner H, Verkhratsky A. Inseparable tandem: evolution chooses ATP and Ca2+ to control life, death and cellular signalling. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0419. [PMID: 27377729 DOI: 10.1098/rstb.2015.0419] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 01/01/2023] Open
Abstract
From the very dawn of biological evolution, ATP was selected as a multipurpose energy-storing molecule. Metabolism of ATP required intracellular free Ca(2+) to be set at exceedingly low concentrations, which in turn provided the background for the role of Ca(2+) as a universal signalling molecule. The early-eukaryote life forms also evolved functional compartmentalization and vesicle trafficking, which used Ca(2+) as a universal signalling ion; similarly, Ca(2+) is needed for regulation of ciliary and flagellar beat, amoeboid movement, intracellular transport, as well as of numerous metabolic processes. Thus, during evolution, exploitation of atmospheric oxygen and increasingly efficient ATP production via oxidative phosphorylation by bacterial endosymbionts were a first step for the emergence of complex eukaryotic cells. Simultaneously, Ca(2+) started to be exploited for short-range signalling, despite restrictions by the preset phosphate-based energy metabolism, when both phosphates and Ca(2+) interfere with each other because of the low solubility of calcium phosphates. The need to keep cytosolic Ca(2+) low forced cells to restrict Ca(2+) signals in space and time and to develop energetically favourable Ca(2+) signalling and Ca(2+) microdomains. These steps in tandem dominated further evolution. The ATP molecule (often released by Ca(2+)-regulated exocytosis) rapidly grew to be the universal chemical messenger for intercellular communication; ATP effects are mediated by an extended family of purinoceptors often linked to Ca(2+) signalling. Similar to atmospheric oxygen, Ca(2+) must have been reverted from a deleterious agent to a most useful (intra- and extracellular) signalling molecule. Invention of intracellular trafficking further increased the role for Ca(2+) homeostasis that became critical for regulation of cell survival and cell death. Several mutually interdependent effects of Ca(2+) and ATP have been exploited in evolution, thus turning an originally unholy alliance into a fascinating success story.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- Helmut Plattner
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Alexei Verkhratsky
- Faculty of Biological Sciences, University of Manchester, Manchester M13 9PT, UK Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod 603022, Russia
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Abstract
Centrin belongs to the calcium-binding super-family, and is essential for the microtubule-organizing center (MTOC).
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Affiliation(s)
- Yaqin Zhao
- Institute of Molecular Science
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Xiaofang Cui
- Institute of Molecular Science
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
| | - Binsheng Yang
- Institute of Molecular Science
- Key Laboratory of Chemical Biology
- Molecular Engineering of Ministry of Education
- Shanxi University
- Taiyuan 030006
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Shi E, Zhang W, Zhao Y, Yang B. Binding of Euplotes octocarinatus centrin to peptide from xeroderma pigmentosum group C protein (XPC). RSC Adv 2017. [DOI: 10.1039/c7ra03079g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Trp is buried in the hydrophobic cavity, the peptide folds into an α-helix, and the interaction is enthalpically driven from ITC.
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Affiliation(s)
- Enxian Shi
- Institute of Molecular Science
- Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry
- Shanxi University
- Taiyuan 030006
- PR China
| | - Wenlong Zhang
- Institute of Molecular Science
- Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry
- Shanxi University
- Taiyuan 030006
- PR China
| | - Yaqin Zhao
- Institute of Molecular Science
- Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry
- Shanxi University
- Taiyuan 030006
- PR China
| | - Binsheng Yang
- Institute of Molecular Science
- Key Laboratory of Chemical Biology of Molecular Engineering of Education Ministry
- Shanxi University
- Taiyuan 030006
- PR China
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Dutcher SK, O'Toole ET. The basal bodies of Chlamydomonas reinhardtii. Cilia 2016; 5:18. [PMID: 27252853 PMCID: PMC4888484 DOI: 10.1186/s13630-016-0039-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/09/2016] [Indexed: 12/13/2022] Open
Abstract
The unicellular green alga, Chlamydomonas reinhardtii, is a biflagellated cell that can swim or glide. C. reinhardtii cells are amenable to genetic, biochemical, proteomic, and microscopic analysis of its basal bodies. The basal bodies contain triplet microtubules and a well-ordered transition zone. Both the mother and daughter basal bodies assemble flagella. Many of the proteins found in other basal body-containing organisms are present in the Chlamydomonas genome, and mutants in these genes affect the assembly of basal bodies. Electron microscopic analysis shows that basal body duplication is site-specific and this may be important for the proper duplication and spatial organization of these organelles. Chlamydomonas is an excellent model for the study of basal bodies as well as the transition zone.
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Sawant DB, Majumder S, Perkins JL, Yang CH, Eyers PA, Fisk HA. Centrin 3 is an inhibitor of centrosomal Mps1 and antagonizes centrin 2 function. Mol Biol Cell 2015; 26:3741-53. [PMID: 26354417 PMCID: PMC4626060 DOI: 10.1091/mbc.e14-07-1248] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/04/2015] [Indexed: 11/11/2022] Open
Abstract
Centrins are a family of small, calcium-binding proteins with diverse cellular functions that play an important role in centrosome biology. We previously identified centrin 2 and centrin 3 (Cetn2 and Cetn3) as substrates of the protein kinase Mps1. However, although Mps1 phosphorylation sites control the function of Cetn2 in centriole assembly and promote centriole overproduction, Cetn2 and Cetn3 are not functionally interchangeable, and we show here that Cetn3 is both a biochemical inhibitor of Mps1 catalytic activity and a biological inhibitor of centrosome duplication. In vitro, Cetn3 inhibits Mps1 autophosphorylation at Thr-676, a known site of T-loop autoactivation, and interferes with Mps1-dependent phosphorylation of Cetn2. The cellular overexpression of Cetn3 attenuates the incorporation of Cetn2 into centrioles and centrosome reduplication, whereas depletion of Cetn3 generates extra centrioles. Finally, overexpression of Cetn3 reduces Mps1 Thr-676 phosphorylation at centrosomes, and mimicking Mps1-dependent phosphorylation of Cetn2 bypasses the inhibitory effect of Cetn3, suggesting that the biological effects of Cetn3 are due to the inhibition of Mps1 function at centrosomes.
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Affiliation(s)
- Dwitiya B Sawant
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Shubhra Majumder
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Jennifer L Perkins
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Ching-Hui Yang
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Harold A Fisk
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210
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Grecu D, Assairi L. CK2 phosphorylation of human centrins 1 and 2 regulates their binding to the DNA repair protein XPC, the centrosomal protein Sfi1 and the phototransduction protein transducin β. FEBS Open Bio 2014; 4:407-19. [PMID: 24918055 PMCID: PMC4050191 DOI: 10.1016/j.fob.2014.04.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/10/2014] [Accepted: 04/10/2014] [Indexed: 11/24/2022] Open
Abstract
Centrins are calcium-binding proteins that can interact with several cellular targets (Sfi1, XPC, Sac3 and transducin β) through the same hydrophobic triad. However, two different orientations of the centrin-binding motif have been observed: W(1)xxL(4)xxxL(8) for XPC (xeroderma pigmentosum group C protein) and the opposite orientation L(8)xxxL(4)xxW(1) for Sfi1 (suppressor of fermentation-induced loss of stress resistance protein 1), Sac3 and transducin β. Centrins are also phosphorylated by several protein kinases, among which is CK2. The purpose of this study was to determine the binding mechanism of human centrins to three targets (transducin β, Sfi1 and XPC), and the effects of in vitro phosphorylation by CK2 of centrins 1 and 2 with regard to this binding mechanism. We identified the centrin-binding motif at the COOH extremity of transducin β. Human centrin 1 binds to transducin β only in the presence of calcium with a binding constant lower than the binding constant observed for Sfi1 and for XPC. The affinity constants of centrin 1 were 0.10 10(6) M(-1), 249 10(6) M(-1) and 52.5 10(6) M(-1) for Trd, R17-Sfi1 and P17-XPC respectively. CK2 phosphorylates human centrin 1 at residue T138 and human centrin 2 at residues T138 and S158. Consequently CK2 phosphorylation abolished the binding of centrin 1 to transducin β and reduced the binding to Sfi1 and XPC. CK2 phosphorylation of centrin 2 at T138 and S158 abolished the binding to Sfi1 as assessed using a C-HsCen2 T138D-S158D phosphomimetic form of centrin 2.
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Affiliation(s)
- Dora Grecu
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France
| | - Liliane Assairi
- Institut Curie-Centre de Recherche, F-91405 Orsay Cédex, France
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Merten P, Lechtreck KF, Melkonian M. Nucleus Basal Body Connector ofDunaliella: Threshold Concentration of Calcium Necessary forin vitroContraction*. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1995.tb00824.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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23
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Grecu D, Blouquit Y, Assairi L. The E144 residue of Scherffelia dubia centrin discriminates between the DNA repair protein XPC and the centrosomal protein Sfi1. FEBS Open Bio 2013; 4:33-42. [PMID: 24371720 PMCID: PMC3871271 DOI: 10.1016/j.fob.2013.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 11/22/2013] [Indexed: 11/27/2022] Open
Abstract
Centrins are members of the EF-hand family of calcium-binding proteins, which are highly conserved among eukaryotes. Centrins bind to several cellular targets, through a hydrophobic triad. However, the W(1)xxL(4)xxxL(8) triad in XPC (Xeroderma Pigmentosum Group C protein) is found in the reverse orientation, as in the L(8)xxxL(4)xxW(1) triad in Sfi1 (Suppressor of Fermentation-Induced loss of stress resistance protein 1). As shown by previous NMR studies of human centrin 2 in complex with XPC or Sfi1, the E148 residue of human centrin 2 is in contact with XPC but is pushed away from the triad of Sfi1. We corroborated these findings using site-directed mutagenesis to generate mutations in Scherffelia dubia centrin (SdCen) and by using isothermal titration calorimetry to analyze the binding affinity of these mutants to XPC and Sfi1. We mutated the F109 residue, which is the main residue involved in target binding regardless of triad orientation, and the E144 residue, which was thought to be involved only in XPC binding. The F109L mutation reduced the binding of SdCen to XPC and Sfi1 and the negative effect was greater upon temperature increase. By contrast, the E144A mutation reduced the binding to XPC but had no effect on Sfi1 binding. The F109L-E144A mutation enhanced the negative effect of the two single mutations on XPC binding. Sfi1 proteins from Ostreococcus lucimarinus and Ostreococcus tauri, which belong to the same clade as S. dubia, were also investigated. A comparative analysis shows that the triad residues are more conserved than those in human Sfi1.
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Affiliation(s)
- Dora Grecu
- Institut Curie, Centre de Recherche, Orsay Cédex F-91405, France
| | - Yves Blouquit
- Institut Curie, Centre de Recherche, Orsay Cédex F-91405, France
| | - Liliane Assairi
- Institut Curie, Centre de Recherche, Orsay Cédex F-91405, France
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24
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Dantas TJ, Daly OM, Conroy PC, Tomas M, Wang Y, Lalor P, Dockery P, Ferrando-May E, Morrison CG. Calcium-binding capacity of centrin2 is required for linear POC5 assembly but not for nucleotide excision repair. PLoS One 2013; 8:e68487. [PMID: 23844208 PMCID: PMC3699651 DOI: 10.1371/journal.pone.0068487] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 05/29/2013] [Indexed: 12/25/2022] Open
Abstract
Centrosomes, the principal microtubule-organising centres in animal cells, contain centrins, small, conserved calcium-binding proteins unique to eukaryotes. Centrin2 binds to xeroderma pigmentosum group C protein (XPC), stabilising it, and its presence slightly increases nucleotide excision repair (NER) activity in vitro. In previous work, we deleted all three centrin isoforms present in chicken DT40 cells and observed delayed repair of UV-induced DNA lesions, but no centrosome abnormalities. Here, we explore how centrin2 controls NER. In the centrin null cells, we expressed centrin2 mutants that cannot bind calcium or that lack sites for phosphorylation by regulatory kinases. Expression of any of these mutants restored the UV sensitivity of centrin null cells to normal as effectively as expression of wild-type centrin. However, calcium-binding-deficient and T118A mutants showed greatly compromised localisation to centrosomes. XPC recruitment to laser-induced UV-like lesions was only slightly slower in centrin-deficient cells than in controls, and levels of XPC and its partner HRAD23B were unaffected by centrin deficiency. Interestingly, we found that overexpression of the centrin interactor POC5 leads to the assembly of linear, centrin-dependent structures that recruit other centrosomal proteins such as PCM-1 and NEDD1. Together, these observations suggest that assembly of centrins into complex structures requires calcium binding capacity, but that such assembly is not required for centrin activity in NER.
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Affiliation(s)
- Tiago J. Dantas
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Owen M. Daly
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Pauline C. Conroy
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Martin Tomas
- Bioimaging Center, University of Konstanz, Konstanz, Germany
- Department of Physics, Center for Applied Photonics, University of Konstanz, Konstanz, Germany
| | - Yifan Wang
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Pierce Lalor
- Anatomy, School of Medicine, National University of Ireland Galway, Galway, Ireland
| | - Peter Dockery
- Anatomy, School of Medicine, National University of Ireland Galway, Galway, Ireland
| | | | - Ciaran G. Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
- * E-mail:
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25
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Nishi R, Sakai W, Tone D, Hanaoka F, Sugasawa K. Structure-function analysis of the EF-hand protein centrin-2 for its intracellular localization and nucleotide excision repair. Nucleic Acids Res 2013; 41:6917-29. [PMID: 23716636 PMCID: PMC3737541 DOI: 10.1093/nar/gkt434] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Centrin-2 is an evolutionarily conserved, calmodulin-related protein, which is involved in multiple cellular functions including centrosome regulation and nucleotide excision repair (NER) of DNA. Particularly to exert the latter function, complex formation with the XPC protein, the pivotal NER damage recognition factor, is crucial. Here, we show that the C-terminal half of centrin-2, containing two calcium-binding EF-hand motifs, is necessary and sufficient for both its localization to the centrosome and interaction with XPC. In XPC-deficient cells, nuclear localization of overexpressed centrin-2 largely depends on co-overexpression of XPC, and mutational analyses of the C-terminal domain suggest that XPC and the major binding partner in the centrosome share a common binding surface on the centrin-2 molecule. On the other hand, the N-terminal domain of centrin-2 also contains two EF-hand motifs but shows only low-binding affinity for calcium ions. Although the N-terminal domain is dispensable for enhancement of the DNA damage recognition activity of XPC, it contributes to augmenting rather weak physical interaction between XPC and XPA, another key factor involved in NER. These results suggest that centrin-2 may have evolved to bridge two protein factors, one with high affinity and the other with low affinity, thereby allowing delicate regulation of various biological processes.
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Affiliation(s)
- Ryotaro Nishi
- Biosignal Research Center, Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo 657-8501, Japan
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26
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Vonderfecht T, Cookson MW, Giddings TH, Clarissa C, Winey M. The two human centrin homologues have similar but distinct functions at Tetrahymena basal bodies. Mol Biol Cell 2012; 23:4766-77. [PMID: 23087207 PMCID: PMC3521684 DOI: 10.1091/mbc.e12-06-0454] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Centrins are a ubiquitous family of small Ca(2+)-binding proteins found at basal bodies that are placed into two groups based on sequence similarity to the human centrins 2 and 3. Analyses of basal body composition in different species suggest that they contain a centrin isoform from each group. We used the ciliate protist Tetrahymena thermophila to gain a better understanding of the functions of the two centrin groups and to determine their potential redundancy. We have previously shown that the Tetrahymena centrin 1 (Cen1), a human centrin 2 homologue, is required for proper basal body function. In this paper, we show that the Tetrahymena centrin 2 (Cen2), a human centrin 3 homologue, has functions similar to Cen1 in basal body orientation, maintenance, and separation. The two are, however, not redundant. A further examination of human centrin 3 homologues shows that they function in a manner distinct from human centrin 2 homologues. Our data suggest that basal bodies require a centrin from both groups in order to function correctly.
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Affiliation(s)
- Tyson Vonderfecht
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA
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Dantas TJ, Daly OM, Morrison CG. Such small hands: the roles of centrins/caltractins in the centriole and in genome maintenance. Cell Mol Life Sci 2012; 69:2979-97. [PMID: 22460578 PMCID: PMC11114748 DOI: 10.1007/s00018-012-0961-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 02/20/2012] [Accepted: 03/12/2012] [Indexed: 01/11/2023]
Abstract
Centrins are small, highly conserved members of the EF-hand superfamily of calcium-binding proteins that are found throughout eukaryotes. They play a major role in ensuring the duplication and appropriate functioning of the ciliary basal bodies in ciliated cells. They have also been localised to the centrosome, which is the major microtubule organising centre in animal somatic cells. We describe the identification, cloning and characterisation of centrins in multiple eukaryotic species. Although centrins have been implicated in centriole biogenesis, recent results have indicated that centrosome duplication can, in fact, occur in the absence of centrins. We discuss these data and the non-centrosomal functions that are emerging for the centrins. In particular, we discuss the involvement of centrins in nucleotide excision repair, a process that repairs the DNA lesions that are induced primarily by ultraviolet irradiation. We discuss how centrin may be involved in these diverse processes and contribute to nuclear and cytoplasmic events.
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Affiliation(s)
- Tiago J. Dantas
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland
| | - Owen M. Daly
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland
| | - Ciaran G. Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland
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Zhang Y, He CY. Centrins in unicellular organisms: functional diversity and specialization. PROTOPLASMA 2012; 249:459-467. [PMID: 21786168 DOI: 10.1007/s00709-011-0305-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/10/2011] [Indexed: 05/31/2023]
Abstract
Centrins (also known as caltractins) are conserved, EF hand-containing proteins ubiquitously found in eukaryotes. Similar to calmodulins, the calcium-binding EF hands in centrins fold into two structurally similar domains separated by an alpha-helical linker region, shaping like a dumbbell. The small size (15-22 kDa) and domain organization of centrins and their functional diversity/specialization make them an ideal system to study protein structure-function relationship. Here, we review the work on centrins with a focus on their structures and functions characterized in unicellular organisms.
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Affiliation(s)
- Yu Zhang
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
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Zhao Y, Yan J, Song L, Feng Y, Liang A, Yang B. The interaction between lanthanide (III) and N-terminal domain of Euplotes octocarinatus centrin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 87:163-170. [PMID: 22154266 DOI: 10.1016/j.saa.2011.11.032] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/13/2011] [Indexed: 05/31/2023]
Abstract
Centrin, a member of calcium-binding proteins, is an essential component for microtubule-organizing center (MTOC). Lanthanide (Ln) ions can increase amounts, enhance stability and orderliness of microtubules which is an important component of cytoskeleton. To investigate the structural basis of the effect of Ln ions on orderliness of microtubules, we focused on the interactions between the isolated N-terminal domain of Euplotes centrin (N-EoCen) and Ln by some combined biophysical and biochemical methods. Our results suggest that Ln ions may bind to the canonical calcium binding sites on N-EoCen. Taking advantage of ligand competition, we first determined the metal-binding affinities of Nd(3+), Eu(3+), Gd(3+) and Tm(3+) with N-EoCen. Major changes of N-EoCen in secondary and tertiary structure are noted while Ln ions bind with N-EoCen through CD spectra and 2-p-toluidinylnaphthalene-6-sulfonate (TNS) fluorescence. N-EoCen exists in the form of monomer and dimer in the presence of Ln ions. These results can provide some insights into the structural basis of how Ln ions achieve biological effect in cell through the centrin protein.
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Affiliation(s)
- Yaqin Zhao
- Institute of Molecular Science, Shanxi University, Taiyuan 030006, China
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Zhao Y, Yan J, Feng Y, Liang A, Yang B. Analysis of the role of Mg²⁺ on conformational change and target recognition by ciliate Euplotes octocarinatus centrin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2011; 105:60-68. [PMID: 21788140 DOI: 10.1016/j.jphotobiol.2011.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 05/31/2023]
Abstract
The binding of Mg(2+) with the Euplotes octocarinatus centrin (EoCen) and the effect of Mg(2+) on the binding of EoCen with the peptide melittin were examined by spectroscopic methods. In this study, it was found that Mg(2+) may bind with Ca(2+)-binding sites, at least partly, on EoCen, which displays ∼10-fold weaker affinity than Ca(2+). In the presence of Mg(2+), Ca(2+)-saturated EoCen undergoes significant conformational changes resulting in decreased exposure of hydrophobic surfaces on the protein. Additionally, excess Mg(2+) did not change the stoichiometry, but rather reduced the affinity of EoCen to melittin. The Mg(2+)-dependent decrease in the affinities of EoCen to melittin is an intrinsic property of Mg(2+), rather than a nonspecific ionic effect. The inhibitory effect of Mg(2+) on the formation of complexes between EoCen and melittin may contribute to the specificity of EoCen in target activation in response to cellular Ca(2+) concentration fluctuations.
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Affiliation(s)
- Yaqin Zhao
- Institute of Biotechnology, Shanxi University, Taiyuan 030006, China
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31
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Dantas TJ, Wang Y, Lalor P, Dockery P, Morrison CG. Defective nucleotide excision repair with normal centrosome structures and functions in the absence of all vertebrate centrins. ACTA ACUST UNITED AC 2011; 193:307-18. [PMID: 21482720 PMCID: PMC3080269 DOI: 10.1083/jcb.201012093] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Centrin-null cells undergo normal division but are highly sensitive to UV irradiation as a result of impaired DNA repair. The principal microtubule-organizing center in animal cells, the centrosome, contains centrin, a small, conserved calcium-binding protein unique to eukaryotes. Several centrin isoforms exist and have been implicated in various cellular processes including nuclear export and deoxyribonucleic acid (DNA) repair. Although centrins are required for centriole/basal body duplication in lower eukaryotes, centrin functions in vertebrate centrosome duplication are less clear. To define these roles, we used gene targeting in the hyperrecombinogenic chicken DT40 cell line to delete all three centrin genes in individual clones. Unexpectedly, centrin-deficient cells underwent normal cellular division with no detectable cell cycle defects. Light and electron microscopy analyses revealed no significant difference in centrosome composition or ultrastructure. However, centrin deficiency made DT40 cells highly sensitive to ultraviolet (UV) irradiation, with Cetn3 deficiency exacerbating the sensitivity of Cetn4/Cetn2 double mutants. DNA damage checkpoints were intact, but repair of UV-induced DNA damage was delayed in centrin nulls. These data demonstrate a role for vertebrate centrin in nucleotide excision repair.
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Affiliation(s)
- Tiago J Dantas
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway 091 524 411, Ireland
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Abstract
Centrioles are conserved microtubule-based organelles that lie at the core of the animal centrosome and play a crucial role in nucleating the formation of cilia and flagella in most eukaryotes. Centrioles have a complex ultrastructure with ninefold symmetry and a well-defined length. This structure is assembled from a host of proteins, including a variety of disease gene products. Over a century after the discovery of centrioles, the mechanisms underlying the assembly of these fascinating organelles, in particular the establishment of ninefold symmetry and the control of centriole length, are now starting to be uncovered.
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Affiliation(s)
- Juliette Azimzadeh
- Department of Biochemistry and Biophysics, University of California, San Francisco, 94143, USA
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Radu L, Durussel I, Assairi L, Blouquit Y, Miron S, Cox JA, Craescu CT. Scherffelia dubia Centrin Exhibits a Specific Mechanism for Ca2+-Controlled Target Binding. Biochemistry 2010; 49:4383-94. [DOI: 10.1021/bi901764m] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Laura Radu
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Isabelle Durussel
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Liliane Assairi
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Yves Blouquit
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Simona Miron
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
| | - Jos A. Cox
- Department of Biochemistry, University of Geneva, Geneva 4, Switzerland
| | - Constantin T. Craescu
- Institut Curie Centre de Recherche, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
- INSERM U759, Centre Universitaire Paris-Sud, 91405 Orsay Cedex, France
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Martinez-Sanz J, Kateb F, Assairi L, Blouquit Y, Bodenhausen G, Abergel D, Mouawad L, Craescu CT. Structure, Dynamics and Thermodynamics of the Human Centrin 2/hSfi1 Complex. J Mol Biol 2010; 395:191-204. [DOI: 10.1016/j.jmb.2009.10.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 10/16/2009] [Accepted: 10/17/2009] [Indexed: 10/20/2022]
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Lechtreck KF, Luro S, Awata J, Witman GB. HA-tagging of putative flagellar proteins in Chlamydomonas reinhardtii identifies a novel protein of intraflagellar transport complex B. ACTA ACUST UNITED AC 2009; 66:469-82. [PMID: 19382199 DOI: 10.1002/cm.20369] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Proteomic analysis of flagella from the green alga Chlamydomonas reinhardtii has identified over 600 putative flagellar proteins. The genes encoding nine of these not previously characterized plus the previously described PACRG protein were cloned, inserted into a vector adding a triple-HA tag to the C-terminus of the gene product, and transformed into C. reinhardtii. Expression was confirmed by western blotting. Indirect immunofluorescence located all 10 fusion proteins in the flagellum; PACRG was localized to a subset of outer doublet microtubules. For some proteins, additional signal was observed in the cell body. Among the latter was FAP232-HA, which showed a spotted distribution along the flagella and an accumulation at the basal bodies. This pattern is characteristic for intraflagellar transport (IFT) proteins. FAP232-HA co-localized with the IFT protein IFT46 and co-sedimented with IFT particles in sucrose gradients. Furthermore, it co-immunoprecipitated with IFT complex B protein IFT46, but not with IFT complex A protein IFT139. We conclude that FAP232 is a novel component of IFT complex B and rename it IFT25. Homologues of IFT25 are encoded in the genomes of a subset of organisms that assemble cilia or flagella; C. reinhardtii IFT25 is 37% identical to the corresponding human protein. Genes encoding IFT25 homologues are absent from the genomes of organisms that lack cilia and flagella and, interestingly, also from those of Drosophila melanogaster and Caenorhabditis elegans, suggesting that IFT25 has a specialized role in IFT that is not required for the assembly of cilia or flagella in the worm and fly. Cell Motil. Cytoskeleton 2009. (c) 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Karl-Ferdinand Lechtreck
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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Trojan P, Krauss N, Choe HW, Giessl A, Pulvermüller A, Wolfrum U. Centrins in retinal photoreceptor cells: regulators in the connecting cilium. Prog Retin Eye Res 2008; 27:237-59. [PMID: 18329314 DOI: 10.1016/j.preteyeres.2008.01.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Changes in the intracellular Ca2+ concentration regulate the visual signal transduction cascade directly or more often indirectly through Ca2+-binding proteins. Here we focus on centrins, which are members of a highly conserved subgroup of the EF-hand superfamily of Ca2+-binding proteins in photoreceptor cells of the vertebrate retina. Centrins are commonly associated with centrosome-related structures. In mammalian retinal photoreceptor cells, four centrin isoforms are expressed as prominent components in the connecting cilium linking the light-sensitive outer segment compartment with the metabolically active inner segment compartment. Our data indicate that Ca2+-activated centrin isoforms assemble into protein complexes with the visual heterotrimeric G-protein transducin. This interaction of centrins with transducin is mediated by binding to the betagamma-dimer of the heterotrimeric G-protein. More recent findings show that these interactions of centrins with transducin are reciprocally regulated via site-specific phosphorylations mediated by the protein kinase CK2. The assembly of centrin/G-protein complexes is a novel aspect of translocation regulation of signalling proteins in sensory cells, and represents a potential link between molecular trafficking and signal transduction in general.
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Affiliation(s)
- Philipp Trojan
- Institut für Zoologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
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Selvapandiyan A, Kumar P, Morris JC, Salisbury JL, Wang CC, Nakhasi HL. Centrin1 is required for organelle segregation and cytokinesis in Trypanosoma brucei. Mol Biol Cell 2007; 18:3290-301. [PMID: 17567955 PMCID: PMC1951761 DOI: 10.1091/mbc.e07-01-0022] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Centrin is a calcium-binding centrosome/basal body-associated protein involved in duplication and segregation of these organelles in eukaryotes. We had shown that disruption of one of the centrin genes (centrin1) in Leishmania amastigotes resulted in failure of both basal body duplication and cytokinesis. Here, we undertook to define the role of centrin1 (TbCen1) in the duplication and segregation of basal body and its associated organelles kinetoplast and Golgi, as well as its role in cytokinesis of the procyclic form of Trypanosoma brucei by depleting its protein using RNA inhibition methodology. TbCen1-depleted cells showed significant reduction in growth compared with control cells. Morphological analysis of these cells showed they were large and pleomorphic with multiple detached flagella. Both immunofluorescence assays using organelle-specific antibodies and electron microscopic analysis showed that TbCen1-deficient cells contained multiple basal bodies, kinetoplasts, Golgi, and nuclei. These multiple organelles were, however, closely clustered together, indicating duplication without segregation in the absence of centrin. This failure in organelle segregation may be the likely cause of inhibition of cytokinesis, suggesting for the first time a new and unique role for centrin in the segregation of organelles without affecting their multiplication in the procyclic form of T. brucei.
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Affiliation(s)
- Angamuthu Selvapandiyan
- *Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892
| | - Praveen Kumar
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143
| | - James C. Morris
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634; and
| | | | - Ching C. Wang
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143
| | - Hira L. Nakhasi
- *Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892
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VACCHIANO EMANUEL, DREISBACH AMY, LOCASCIO DAVE, CASTANEDA LISA, VIVIAN TOM, BUHSE HOWARDE. Morphogenetic Transitions and Cytoskeletal Elements of the Stalked Zooid and the Telotroch Stages in the Peritrich CiliateVorticella convallaria. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1550-7408.1992.tb01288.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Park JH, Pulvermüller A, Scheerer P, Rausch S, Giessl A, Höhne W, Wolfrum U, Hofmann KP, Ernst OP, Choe HW, Krauss N. Insights into functional aspects of centrins from the structure of N-terminally extended mouse centrin 1. Vision Res 2006; 46:4568-74. [PMID: 17027898 DOI: 10.1016/j.visres.2006.07.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Revised: 07/28/2006] [Accepted: 07/28/2006] [Indexed: 11/30/2022]
Abstract
Centrins are members of the family of Ca(2+)-binding EF-hand proteins. In photoreceptor cells, centrin isoform 1 is specifically localized in the non-motile cilium. This connecting cilium links the light-sensitive outer segment with the biosynthetic active inner segment of the photoreceptor cell. All intracellular exchanges between these compartments have to occur through this cilium. Three-dimensional structures of centrins from diverse organisms are known, showing that the EF-hand motifs of the N-terminal domains adopt closed conformations, while the C-terminal EF-hand motifs have open conformations. The crystal structure of an N-terminally extended mouse centrin 1 (MmCen1-L) resembles the overall structure of troponin C in its two Ca(2+) bound form. Within the N-terminal extension in MmCen1-L, residues W24 and R25 bind to the C-terminal domain of centrin 1 in a target-protein-like geometry. Here, we discuss this binding mode in connection with putative interaction sites of the target-protein transducin and the self-assembly of centrins.
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Affiliation(s)
- Jung Hee Park
- Institut für Medizinische Physik und Biophysik, Charité-Universitätsmedizin Berlin, Ziegelstr. 5-9, D-10098 Berlin, Germany
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Martinez-Sanz J, Yang A, Blouquit Y, Duchambon P, Assairi L, Craescu CT. Binding of human centrin 2 to the centrosomal protein hSfi1. FEBS J 2006; 273:4504-15. [PMID: 16956364 DOI: 10.1111/j.1742-4658.2006.05456.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
hSfi1, a human centrosomal protein with homologs in other eukaryotic organisms, includes 23 repeats, each of 23 amino acids, separated by 10 residue linkers. The main molecular partner in the centrosome is a small, calcium-binding EF-hand protein, the human centrin 2. Using isothermal titration calorimetry experiments, we characterized the centrin-binding capacity of three isolated hSfi1 repeats, two exhibiting the general consensus motif and the third being the unique Pro-containing human repeat. The two standard peptides bind human centrin 2 and its isolated C-terminal domain with high affinity (approximately 10(7) M(-1)) by an enthalpy-driven mechanism, with a moderate Ca2+ dependence. The Pro-containing repeat shows a binding affinity that is two orders of magnitude lower. The target binding site is localized within the C-terminal domain of human centrin 2. Fluorescence titration and NMR spectroscopy show that the well-conserved Trp residue situated in the C-terminus of each repeat is deeply embedded in a protein hydrophobic cavity, indicating that the peptide direction is reversed relative to previously studied centrin targets. The present results suggest that almost all of the repeats of the Sfi1 protein may independently bind centrin molecules. On the basis of this hypothesis and previous studies on centrin self-assembly, we propose a working model for the role of centrin-Sfi1 interactions in the dynamic structure of centrosome-associated contractile fibers.
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Affiliation(s)
- Juan Martinez-Sanz
- The Integrative Imaging Unit, INSERM U759/Institut Curie-Recherche, Centre Universitaire Paris-Sud, Orsay Cedex, France
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Craig TA, Benson LM, Bergen HR, Venyaminov SY, Salisbury JL, Ryan ZC, Thompson JR, Sperry J, Gross ML, Kumar R. Metal-binding properties of human centrin-2 determined by micro-electrospray ionization mass spectrometry and UV spectroscopy. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2006; 17:1158-71. [PMID: 16750384 DOI: 10.1016/j.jasms.2006.04.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 04/03/2006] [Accepted: 04/13/2006] [Indexed: 05/10/2023]
Abstract
We analyzed the metal-binding properties of human centrin-2 (HsCen-2) and followed the changes in HsCen-2 structure upon metal-binding using micro-electrospray ionization mass spectrometry (muESI-MS). Apo-HsCen-2 is mostly monomeric. The ESI spectra of HsCen-2 show two charge-state distributions, representing two conformations of the protein. HsCen-2 binds four moles calcium/mol protein: one mol of calcium with high affinity, one additional mol of calcium with lower affinity, and two moles of calcium at low affinity sites. HsCen-2 binds four moles of magnesium/mol protein. The conformation giving the lower charge-state HsCen-2 by ESI, binds calcium and magnesium more readily than does the higher charge-state HsCen-2. Both conformations of HsCen-2 bind calcium more readily than magnesium. Calcium was more effective in displacing magnesium bound to HsCen-2 than vice versa. Binding of a peptide from a known binding partner, the xeroderma pigmentosum complementation group protein C (XPC), to apo-HsCen-2, occurs in the presence or the absence of calcium. Near and far-UV CD spectra of HsCen-2 show little difference with addition of calcium or magnesium. Minor changes in secondary structure are noted. Melting curves derived from temperature dependence of molar ellipticity at 222 nm for HsCen-2 show that calcium increases protein stability whereas magnesium does not. Delta 25 HsCen-2 behaves similarly to HsCen-2. We conclude that HsCen-2 binds calcium and magnesium and that calcium modulates HsCen-2 structure and function by increasing its stability without undergoing significant changes in secondary or tertiary structure.
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Affiliation(s)
- Theodore A Craig
- Department of Medicine, Mayo Clinic College of Medicine and Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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Katsaros C, Karyophyllis D, Galatis B. Cytoskeleton and morphogenesis in brown algae. ANNALS OF BOTANY 2006; 97:679-93. [PMID: 16467352 PMCID: PMC2803427 DOI: 10.1093/aob/mcl023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2005] [Revised: 11/05/2005] [Accepted: 11/28/2005] [Indexed: 05/06/2023]
Abstract
BACKGROUND Morphogenesis on a cellular level includes processes in which cytoskeleton and cell wall expansion are strongly involved. In brown algal zygotes, microtubules (MTs) and actin filaments (AFs) participate in polarity axis fixation, cell division and tip growth. Brown algal vegetative cells lack a cortical MT cytoskeleton, and are characterized by centriole-bearing centrosomes, which function as microtubule organizing centres. SCOPE Extensive electron microscope and immunofluorescence studies of MT organization in different types of brown algal cells have shown that MTs constitute a major cytoskeletal component, indispensable for cell morphogenesis. Apart from participating in mitosis and cytokinesis, they are also involved in the expression and maintenance of polarity of particular cell types. Disruption of MTs after Nocodazole treatment inhibits cell growth, causing bulging and/or bending of apical cells, thickening of the tip cell wall, and affecting the nuclear positioning. Staining of F-actin using Rhodamine-Phalloidin, revealed a rich network consisting of perinuclear, endoplasmic and cortical AFs. AFs participate in mitosis by the organization of an F-actin spindle and in cytokinesis by an F-actin disc. They are also involved in the maintenance of polarity of apical cells, as well as in lateral branch initiation. The cortical system of AFs was found related to the orientation of cellulose microfibrils (MFs), and therefore to cell wall morphogenesis. This is expressed by the coincidence in the orientation between cortical AFs and the depositing MFs. Treatment with cytochalasin B inhibits mitosis and cytokinesis, as well as tip growth of apical cells, and causes abnormal deposition of MFs. CONCLUSIONS Both the cytoskeletal elements studied so far, i.e. MTs and AFs are implicated in brown algal cell morphogenesis, expressed in their relationship with cell wall morphogenesis, polarization, spindle organization and cytokinetic mechanism. The novelty is the role of AFs and their possible co-operation with MTs.
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Affiliation(s)
- Christos Katsaros
- University of Athens, Faculty of Biology, Department of Botany, Athens 157 84, Greece.
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Abstract
Centrosomes are dynamic organelles involved in many aspects of cell function and growth. Centrosomes act as microtubule organizing centers, and provide a site for concerted regulation of cell cycle progression. While there is diversity in microtubule organizing center structure among eukaryotes, many centrosome components, such as centrin, are conserved. Experimental analysis has provided an outline to describe centrosome duplication, and numerous centrosome components have been identified. Even so, more work is needed to provide a detailed understanding of the interactions between centrosome components and their roles in centrosome function and duplication. Precise duplication of centrosomes once during each cell cycle ensures proper mitotic spindle formation and chromosome segregation. Defects in centrosome duplication or function are linked to human diseases including cancer. Here we provide a multifaceted look at centrosomes with a detailed summary of the centrosome cycle.
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Ruiz F, Garreau de Loubresse N, Klotz C, Beisson J, Koll F. Centrin Deficiency in Paramecium Affects the Geometry of Basal-Body Duplication. Curr Biol 2005; 15:2097-106. [PMID: 16332534 DOI: 10.1016/j.cub.2005.11.038] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 10/12/2005] [Accepted: 11/08/2005] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ciliary or flagellar basal bodies and centrioles share the same architecture and remarkable property of duplicating once per cell cycle. Duplication is known to proceed by budding of the daugther organelle close to and at right angles to the mother structure, but the molecular basis of this geometry remains unknown. Among the handful of proteins implicated in basal-body/centriole duplication, centrins seem required in all eukaryotes tested, but their mode of action is not clear. We have investigated centrin function in Paramecium, whose cortical organization allows detection of any spatial or temporal alteration in the pattern of basal-body duplication. RESULTS We have characterized two pairs of genes, PtCEN2a and PtCEN2b as well as PtCEN3a and PtCEN3b, orthologs of HsCEN2 and HsCEN3, respectively. GFP tags revealed different localization for the two pairs of gene products, at basal bodies or on basal-body-associated filamentous arrays, respectively. Centrin depletion induced by RNAi caused mislocalization of the neoformed basal bodies: abnormal site of budding (PtCen2ap) or absence of separation between mother and daughter organelles (PtCen3ap). Over successive divisions, new basal bodies continued to be assembled, but internalization of the mispositionned basal bodies led to a progressive decrease in the number of cortical basal bodies. CONCLUSIONS Our observations show that centrins (1) are required to define the site and polarities of duplication and to sever the mother-daughter links and (2) play no triggering or instrumental role in assembly. Our data underscore the biological importance of the geometry of the duplication process.
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Affiliation(s)
- Françoise Ruiz
- Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, 91190 Gif-sur-Yvette, France.
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Geimer S, Melkonian M. Centrin scaffold in Chlamydomonas reinhardtii revealed by immunoelectron microscopy. EUKARYOTIC CELL 2005; 4:1253-63. [PMID: 16002651 PMCID: PMC1168961 DOI: 10.1128/ec.4.7.1253-1263.2005] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the flagellate green alga Chlamydomonas reinhardtii the Ca(2+)-binding EF-hand protein centrin is encoded by a single-copy gene. Previous studies have localized the protein to four distinct structures in the flagellar apparatus: the nucleus-basal body connector, the distal connecting fiber, the flagellar transitional region, and the axoneme. To explain the disjunctive distribution of centrin, the interaction of centrin with as yet unknown specific centrin-binding proteins has been implied. Here, we demonstrate using serial section postembedding immunoelectron microscopy of isolated cytoskeletons that centrin is located in additional structures (transitional fibers and basal body lumen) and that the centrin-containing structures of the basal apparatus are likely part of a continuous filamentous scaffold that extends from the nucleus to the flagellar bases. In addition, we show that centrin is located in the distal lumen of the basal body in a rotationally asymmetric structure, the V-shaped filament system. This novel centrin-containing structure has also been detected near the distal end of the probasal bodies. Taken together, these results suggest a role for a rotationally asymmetric centrin "seed" in the growth and development of the centrin scaffold following replication of the basal apparatus.
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Affiliation(s)
- Stefan Geimer
- Universität Bayreuth, Biologie/Elektronenmikroskopie NW I / B 1, Universitätsstr. 30, D-95447 Bayreuth, Germany.
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Maloney MS, McDaniel WS, Locknar SA, Torlina HM. Identification and localization of a protein immunologically related to Caltractin (Centrin) in the Myonemes and Membranelles of the Heterotrich ciliate Stentor coeruleus. J Eukaryot Microbiol 2005; 52:328-38. [PMID: 16014010 DOI: 10.1111/j.1550-7408.2005.00048x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The contractile properties of the myonemes of Stentor are very similar to caltractin (centrin)-containing fibers of other organisms. We investigated whether the calcium-binding protein caltractin was present in Stentor by using three different antibodies to caltractin or caltractin-related proteins, in conjunction with immunofluorescence microscopy and protein blotting. Immunofluorescence demonstrated that a protein immunologically similar to caltractin is present in the myonemes and in the bases of the membranelles of Stentor. The localization to the myonemes is observed in intact cells, osmotically lysed cells, and isolated cortices. Double-label immunofluorescence with anti-alpha-tubulin and anti-caltractin antibodies showed that the fluorescence in the myonemes was not in the overlying Km fibers. The myonemes in the posterior one-third of the cell appear as thick fibers with no cross-bridging. They become thinner as they approach the anterior end of the cell and show extensive cross-bridging here. Staining in the bases of the membranelles shows a distinct comma-like immunofluorescence pattern similar to that seen with protargol-stained cells and SEM views of the membranellar band reported by others. Western blots demonstrated that the caltractin-like protein in Stentor has an apparent molecular weight of 23 kDa compared with the 20-kDa protein from Chlamydomonas and is a calcium-binding protein.
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Affiliation(s)
- Michael S Maloney
- Department of Biological Sciences, Butler University, Indianapolis, IN 46208, USA.
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Ueyama S, Katsumaru H, Suzaki T, Nakaoka Y. Halteria grandinella: a rapid swimming ciliate with a high frequency of ciliary beating. ACTA ACUST UNITED AC 2005; 60:214-21. [PMID: 15754357 DOI: 10.1002/cm.20056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A ciliated protozoan, Halteria grandinella, swam backward rapidly with a migration distance per second attaining 100 times the cell size. This high swimming velocity was accompanied by a high frequency of ciliary beating. Recordings with a high-speed digital video (10(3) frames/s) revealed that the frequency during forward and backward swimming was, respectively, 105 +/- 10 Hz and 260 +/- 30 Hz. These frequencies are the highest among cilia and flagella reported to date. Electron microscopic observation of the ciliary structure confirmed normal 9 + 2 arrangements of the axoneme except that cilia for migration are bundled into membranelles. Ciliary beating of saponin-treated cells was reactivated by the addition of Mg2+ -ATP, although the beating amplitude was smaller than that of intact cells. Kinetic analysis of the ATP-dependent increase of beating frequency revealed that the maximal frequency in the presence of free Ca2+ and 0.9 microM Ca2+ was approximately 60 and 110 Hz, respectively. A possible mechanism to increase beating frequency with Ca2+ is discussed.
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Affiliation(s)
- Sumiko Ueyama
- Biophysical Dynamics Laboratories, Graduate School of Frontier Bioscience, Osaka University, Toyonaka, Osaka, Japan
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Nishi R, Okuda Y, Watanabe E, Mori T, Iwai S, Masutani C, Sugasawa K, Hanaoka F. Centrin 2 stimulates nucleotide excision repair by interacting with xeroderma pigmentosum group C protein. Mol Cell Biol 2005; 25:5664-74. [PMID: 15964821 PMCID: PMC1156980 DOI: 10.1128/mcb.25.13.5664-5674.2005] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Xeroderma pigmentosum group C (XPC) protein plays a key role in DNA damage recognition in global genome nucleotide excision repair (NER). The protein forms in vivo a heterotrimeric complex involving one of the two human homologs of Saccharomyces cerevisiae Rad23p and centrin 2, a centrosomal protein. Because centrin 2 is dispensable for the cell-free NER reaction, its role in NER has been unclear. Binding experiments with a series of truncated XPC proteins allowed the centrin 2 binding domain to be mapped to a presumed alpha-helical region near the C terminus, and three amino acid substitutions in this domain abrogated interaction with centrin 2. Human cell lines stably expressing the mutant XPC protein exhibited a significant reduction in global genome NER activity. Furthermore, centrin 2 enhanced the cell-free NER dual incision and damaged DNA binding activities of XPC, which likely require physical interaction between XPC and centrin 2. These results reveal a novel vital function for centrin 2 in NER, the potentiation of damage recognition by XPC.
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Affiliation(s)
- Ryotaro Nishi
- Cellular Physiology Laboratory, RIKEN Discovery Research Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Molinier J, Ramos C, Fritsch O, Hohn B. CENTRIN2 modulates homologous recombination and nucleotide excision repair in Arabidopsis. THE PLANT CELL 2004; 16:1633-43. [PMID: 15155891 PMCID: PMC490051 DOI: 10.1105/tpc.021378] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2004] [Accepted: 03/17/2004] [Indexed: 05/17/2023]
Abstract
A genetic screen of a population of Arabidopsis thaliana lines exhibiting enhanced somatic homologous recombination yielded a mutant affected in expression of a gene encoding a caltractin-like protein (centrin). The hyperrecombinogenic phenotype could be reproduced using RNA interference (RNAi) technology. Both the original mutant and the RNAi plants exhibited a moderate UV-C sensitivity as well as a reduced efficiency of in vitro repair of UV-damaged DNA. Transcription profiling of the mutant showed that expression of components of the nucleotide excision repair (NER) pathway and of factors involved in other DNA repair processes were significantly changed. Our data suggest an indirect involvement of centrin in recombinational DNA repair via the modulation of the NER pathway. These findings thus point to a novel interconnection between an early step of NER and homologous recombination, which may play a critical role in plant DNA repair.
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Affiliation(s)
- Jean Molinier
- Friedrich Miescher-Institute for Biomedical Research, CH-4058 Basel, Switzerland.
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Sakato M, King SM. Design and regulation of the AAA+ microtubule motor dynein. J Struct Biol 2004; 146:58-71. [PMID: 15037237 DOI: 10.1016/j.jsb.2003.09.026] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2003] [Revised: 09/22/2003] [Indexed: 11/19/2022]
Abstract
Dyneins are highly complex molecular motors that transport their attached cargo towards the minus end of microtubules. These enzymes are required for many essential motile activities within the cytoplasm and also power eukaryotic cilia and flagella. Each dynein contains one or more heavy chain motor units that consist of an N-terminal stem domain that is involved in cargo attachment, and six AAA+ domains (AAA1-6) plus a C-terminal globular segment that are arranged in a heptameric ring. At least one AAA+ domain (AAA1) is capable of ATP binding and hydrolysis, and the available data suggest that one or more additional domains also may bind nucleotide. The ATP-sensitive microtubule binding site is located at the tip of a 10nm coiled coil stalk that emanates from between AAA4 and AAA5. The function of this motor both in the cytoplasm and the flagellum must be tightly regulated in order to result in useful work. Consequently, dyneins also contain a series of additional components that serve to define the cargo-binding properties of the enzyme and which act as sensors to transmit regulatory inputs to the motor units. Here we describe the two basic dynein designs and detail the various regulatory systems that impinge on this motor within the eukaryotic flagellum.
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Affiliation(s)
- Miho Sakato
- Department of Biochemistry, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA
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