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Tang J, Li J, Lian J, Huang Y, Zhang Y, Lu Y, Zhong G, Wang Y, Zhang Z, Bai X, Fang M, Wu L, Shen H, Wu J, Wang Y, Zhang L, Zhang H. CDK2-activated TRIM32 phosphorylation and nuclear translocation promotes radioresistance in triple-negative breast cancer. J Adv Res 2024; 61:239-251. [PMID: 37734566 DOI: 10.1016/j.jare.2023.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/04/2023] [Accepted: 09/14/2023] [Indexed: 09/23/2023] Open
Abstract
INTRODUCTION Despite radiotherapy being one of the major treatments for triple-negative breast cancer (TNBC), new molecular targets for its treatment are still required due to radioresistance. CDK2 plays a critical role in TNBC. However, the mechanism by which CDK2 promotes TNBC radioresistance remains to be clearly elucidated. OBJECTIVES We aimed to elucidate the relationship between CDK2 and TRIM32 and the regulation mechanism in TNBC. METHODS We performed immunohistochemical staining to detect nuclear TRIM32, CDK2 and STAT3 on TNBC tissues. Western blot assays and PCR were used to detect the protein and mRNA level changes. CRISPR/Cas9 used to knock out CDK2. shRNA-knockdown and transfection assays also used to knock out target genes. GST pull-down analysis, immunoprecipitation (IP) assay and in vitro isomerization analysis also used. Tumorigenesis studies also used to verify the results in vitro. RESULTS Herein, tripartite motif-containing protein 32 (TRIM32) is revealed as a substrate of CDK2. Radiotherapy promotes the binding of CDK2 and TRIM32, thus leading to increased CDK2-dependent phosphorylation of TRIM32 at serines 328 and 339. This causes the recruitment of PIN1, involved in cis-trans isomerization of TRIM32, resulting in importin α3 binding to TRIM32 and contributing to its nuclear translocation. Nuclear TRIM32 inhibits TC45-dephosphorylated STAT3, Leading to increased transcription of STAT3 and radioresistance in TNBC. These results were validated by clinical prognosis confirmed by the correlative expressions of the critical components of the CDK2/TRIM32/STAT3 signaling pathway. CONCLUSIONS Our findings demonstrate that regulating the CDK2/TRIM32/STAT3 pathway is a promising strategy for reducing radioresistance in TNBC.
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Affiliation(s)
- Jianming Tang
- Department of Radiation Oncology, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, PR China; The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, PR China.
| | - Jing Li
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Jiayan Lian
- Department of Pathology, The 7th Affiliated Hospital of Sun Yat-Sen University, Shenzhen 510275, Guandong, PR China
| | - Yumei Huang
- Cancer Center, Department of Medical Oncology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Shangtang Road 158, Hangzhou, Zhejiang 310014, PR China
| | - Yaqing Zhang
- Department of Obstetrics and Gynecology, Gansu Provincial Maternity and Child-care Hospital, Lanzhou, Gansu 730050, PR China
| | - Yanwei Lu
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, PR China
| | - Guansheng Zhong
- Department of Breast Surgery, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, PR China
| | - Yaqi Wang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Zhitao Zhang
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Xin Bai
- The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Min Fang
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, PR China
| | - Luming Wu
- Gansu International Scientific and Technological Cooperation Base of Reproductive Medicine Transformation Application, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Haofei Shen
- Gansu International Scientific and Technological Cooperation Base of Reproductive Medicine Transformation Application, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Jingyuan Wu
- Gansu International Scientific and Technological Cooperation Base of Reproductive Medicine Transformation Application, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, PR China
| | - Yiqing Wang
- Gansu International Scientific and Technological Cooperation Base of Reproductive Medicine Transformation Application, The First Hospital of Lanzhou University, Lanzhou University, Lanzhou, Gansu 730000, PR China.
| | - Lei Zhang
- Department of Radiation Oncology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, PR China.
| | - Haibo Zhang
- Cancer Center, Department of Radiation Oncology, Zhejiang Provincial People's Hospital (Affiliated People's Hospital), Hangzhou Medical College, Hangzhou, Zhejiang 310014, PR China.
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Araujo-Abad S, Rizzuti B, Vidal M, Abian O, Fárez-Vidal ME, Velazquez-Campoy A, de Juan Romero C, Neira JL. Unveiling the Binding between the Armadillo-Repeat Domain of Plakophilin 1 and the Intrinsically Disordered Transcriptional Repressor RYBP. Biomolecules 2024; 14:561. [PMID: 38785968 PMCID: PMC11117474 DOI: 10.3390/biom14050561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/29/2024] [Accepted: 05/04/2024] [Indexed: 05/25/2024] Open
Abstract
Plakophilin 1 (PKP1), a member of the p120ctn subfamily of the armadillo (ARM)-repeat-containing proteins, is an important structural component of cell-cell adhesion scaffolds although it can also be ubiquitously found in the cytoplasm and the nucleus. RYBP (RING 1A and YY1 binding protein) is a multifunctional intrinsically disordered protein (IDP) best described as a transcriptional regulator. Both proteins are involved in the development and metastasis of several types of tumors. We studied the binding of the armadillo domain of PKP1 (ARM-PKP1) with RYBP by using in cellulo methods, namely immunofluorescence (IF) and proximity ligation assay (PLA), and in vitro biophysical techniques, namely fluorescence, far-ultraviolet (far-UV) circular dichroism (CD), and isothermal titration calorimetry (ITC). We also characterized the binding of the two proteins by using in silico experiments. Our results showed that there was binding in tumor and non-tumoral cell lines. Binding in vitro between the two proteins was also monitored and found to occur with a dissociation constant in the low micromolar range (~10 μM). Finally, in silico experiments provided additional information on the possible structure of the binding complex, especially on the binding ARM-PKP1 hot-spot. Our findings suggest that RYBP might be a rescuer of the high expression of PKP1 in tumors, where it could decrease the epithelial-mesenchymal transition in some cancer cells.
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Affiliation(s)
- Salome Araujo-Abad
- Cancer Research Group, Faculty of Engineering and Applied Sciences, Universidad de Las Américas, 170124 Quito, Ecuador;
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Spain
| | - Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy;
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; (O.A.); (A.V.-C.)
| | - Miguel Vidal
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Calle Ramiro de Maeztu, 9, 28040 Madrid, Spain;
| | - Olga Abian
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - María Esther Fárez-Vidal
- Departamento de Bioquímica y Biología Molecular III e Inmunología, Facultad de Medicina, Universidad de Granada, 18016 Granada, Spain;
- Instituto de Investigación Biomédica IBS, Granada, Complejo Hospitalario Universitario de Granada, Universidad de Granada, 18071 Granada, Spain
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; (O.A.); (A.V.-C.)
- Instituto de Investigación Sanitaria Aragón (IIS Aragón), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Camino de Juan Romero
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Spain
- Unidad de Investigación, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Hospital General Universitario de Elche, Camí de l’Almazara 11, 03203 Elche, Spain
| | - José L. Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Spain
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain; (O.A.); (A.V.-C.)
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Araujo-Abad S, Fuentes-Baile M, Rizzuti B, Bazán JF, Villamarin-Ortiz A, Saceda M, Fernández E, Vidal M, Abian O, Velazquez-Campoy A, de Juan Romero C, Neira JL. The intrinsically disordered, epigenetic factor RYBP binds to the citrullinating enzyme PADI4 in cancer cells. Int J Biol Macromol 2023; 246:125632. [PMID: 37399862 DOI: 10.1016/j.ijbiomac.2023.125632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 06/16/2023] [Accepted: 06/28/2023] [Indexed: 07/05/2023]
Abstract
RYBP (Ring1 and YY 1 binding protein) is a multifunctional, intrinsically disordered protein (IDP), best described as a transcriptional regulator. It exhibits a ubiquitin-binding functionality, binds to other transcription factors, and has a key role during embryonic development. RYBP, which folds upon binding to DNA, has a Zn-finger domain at its N-terminal region. By contrast, PADI4 is a well-folded protein and it is one the human isoforms of a family of enzymes implicated in the conversion of arginine to citrulline. As both proteins intervene in signaling pathways related to cancer development and are found in the same localizations within the cell, we hypothesized they may interact. We observed their association in the nucleus and cytosol in several cancer cell lines, by using immunofluorescence (IF) and proximity ligation assays (PLAs). Binding also occurred in vitro, as measured by isothermal titration calorimetry (ITC) and fluorescence, with a low micromolar affinity (~1 μM). AlphaFold2-multimer (AF2) results indicate that PADI4's catalytic domain interacts with the Arg53 of RYBP docking into its active site. As RYBP sensitizes cells to PARP (Poly (ADP-ribose) polymerase) inhibitors, we applied them in combination with an enzymatic inhibitor of PADI4 observing a change in cell proliferation, and the hampering of the interaction of both proteins. This study unveils for the first time the possible citrullination of an IDP, and suggests that this new interaction, whether it involves or not citrullination of RYBP, might have implications in cancer development and progression.
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Affiliation(s)
- Salomé Araujo-Abad
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Centro de Biotecnología, Universidad Nacional de Loja, Avda. Pío Jaramillo Alvarado s/n, 110111 Loja, Ecuador
| | - María Fuentes-Baile
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Unidad de Investigación, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Hospital General Universitario de Elche, Camí de l'Almazara 11, 03203 Elche, Alicante, Spain
| | - Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) - Unidad mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
| | - J Fernando Bazán
- ħ Bioconsulting, LLC, Stillwater, MN, USA; Unit for Structural Biology, Vlaams Instituut voor Biotechnologie-UGent Center for Inflammation Research, Technologiepark 71, 9052 Ghent, Belgium
| | | | - Miguel Saceda
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Unidad de Investigación, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Hospital General Universitario de Elche, Camí de l'Almazara 11, 03203 Elche, Alicante, Spain
| | - Eduardo Fernández
- Instituto de Bioingeniería, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Centro de Investigación Biomédica en Red CIBER-BBN, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Miguel Vidal
- Centro de Investigaciones Biológicas Margarita Salas (CSIC), Calle Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Olga Abian
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) - Unidad mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Adrián Velazquez-Campoy
- Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) - Unidad mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain; Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Camino de Juan Romero
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Unidad de Investigación, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunidad Valenciana (FISABIO), Hospital General Universitario de Elche, Camí de l'Almazara 11, 03203 Elche, Alicante, Spain.
| | - José L Neira
- IDIBE, Universidad Miguel Hernández, 03202 Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI) - Unidad mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain.
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Neira JL, Palomino-Schätzlein M. Folding of the nascent polypeptide chain of a histidine phosphocarrier protein in vitro. Arch Biochem Biophys 2023; 736:109538. [PMID: 36738980 DOI: 10.1016/j.abb.2023.109538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/28/2023] [Accepted: 02/01/2023] [Indexed: 02/05/2023]
Abstract
The phosphotransferase system (PTS), a metabolic pathway formed by five proteins, modulates the use of sugars in bacteria. The second protein in the chain is the histidine phosphocarrier, HPr, with the binding site at His15. The HPr kinase/phosphorylase (HPrK/P), involved in the bacterial use of carbon sources, phosphorylates HPr at Ser46, and it binds at its binding site. The regulator of sigma D protein (Rsd) also binds to HPr at His15. We have designed fragments of HPr, growing from its N-terminus and containing the His15. In this work, we obtained three fragments, HPr38, HPr58 and HPr70, comprising the first thirty-eight, fifty-eight and seventy residues of HPr, respectively. All fragments were mainly disordered, with evidence of a weak native-like, helical population around the binding site, as shown by fluorescence, far-ultraviolet circular dichroism, size exclusion chromatography and nuclear magnetic resonance. Although HPr38, HPr58 and HPr70 were disordered, they could bind to: (i) the N-terminal domain of first protein of the PTS, EIN; (ii) Rsd; and, (iii) HPrK/P, as shown by fluorescence and biolayer interferometry (BLI). The association constants for each protein to any of the fragments were in the low micromolar range, within the same range than those measured in the binding of HPr to each protein. Then, although acquisition of stable, native-like secondary and tertiary structures occurred at the last residues of the polypeptide, the ability to bind protein partners happened much earlier in the growing chain. Binding was related to the presence of the native-like structure around His15.
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Affiliation(s)
- José L Neira
- IDIBE, Universidad Miguel Hernández, 03202, Elche, Alicante, Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Joint Units IQFR-CSIC-BIFI and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018, Zaragoza, Spain.
| | - Martina Palomino-Schätzlein
- ProtoQSAR SL, CEEI-Valencia, Parque Tecnológico de Valencia, Av. Benjamin Franklin 12 (Dep. 8), 46980, Paterna, Valencia, Spain
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Rizzuti B, Iovanna JL, Neira JL. Deciphering the Binding of the Nuclear Localization Sequence of Myc Protein to the Nuclear Carrier Importin α3. Int J Mol Sci 2022; 23:ijms232315333. [PMID: 36499669 PMCID: PMC9739371 DOI: 10.3390/ijms232315333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
The oncoprotein Myc is a transcription factor regulating global gene expression and modulating cell proliferation, apoptosis, and metabolism. Myc has a nuclear localization sequence (NLS) comprising residues Pro320 to Asp328, to allow for nuclear translocation. We designed a peptide comprising such region and the flanking residues (Ala310-Asn339), NLS-Myc, to study, in vitro and in silico, the ability to bind importin α3 (Impα3) and its truncated species (ΔImpα3) depleted of the importin binding domain (IBB), by using fluorescence, circular dichroism (CD), biolayer interferometry (BLI), nuclear magnetic resonance (NMR), and molecular simulations. NLS-Myc interacted with both importin species, with affinity constants of ~0.5 µM (for Impα3) and ~60 nM (for ΔImpα3), as measured by BLI. The molecular simulations predicted that the anchoring of NLS-Myc took place in the major binding site of Impα3 for the NLS of cargo proteins. Besides clarifying the conformational behavior of the isolated NLS of Myc in solution, our results identified some unique properties in the binding of this localization sequence to the nuclear carrier Impα3, such as a difference in the kinetics of its release mechanism depending on the presence or absence of the IBB domain.
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Affiliation(s)
- Bruno Rizzuti
- CNR-NANOTEC, SS Rende (CS), Department of Physics, University of Calabria, 87036 Rende, Italy
- Instituto de Biocomputación y Física de Sistemas Complejos–Unidad Mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Correspondence: (B.R.); (J.L.N.)
| | - Juan L. Iovanna
- Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM U1068, CNRS UMR 7258, Institut Paoli-Calmettes, Aix-Marseille Université, 13288 Marseille, France
| | - José L. Neira
- Instituto de Biocomputación y Física de Sistemas Complejos–Unidad Mixta GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDIBE), Universidad Miguel Hernández, 03202 Elche, Spain
- Correspondence: (B.R.); (J.L.N.)
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Human Enzyme PADI4 Binds to the Nuclear Carrier Importin α3. Cells 2022; 11:cells11142166. [PMID: 35883608 PMCID: PMC9319256 DOI: 10.3390/cells11142166] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 06/13/2022] [Accepted: 07/08/2022] [Indexed: 12/18/2022] Open
Abstract
PADI4 is a peptidyl-arginine deiminase (PADI) involved in the conversion of arginine to citrulline. PADI4 is present in macrophages, monocytes, granulocytes, and several cancer cells. It is the only PADI family member observed within both the nucleus and the cytoplasm. PADI4 has a predicted nuclear localization sequence (NLS) comprising residues Pro56 to Ser83, to allow for nuclear translocation. Recent predictors also suggest that the region Arg495 to Ile526 is a possible NLS. To understand how PADI4 is involved in cancer, we studied the ability of intact PADI4 to bind importin α3 (Impα3), a nuclear transport factor that plays tumor-promoting roles in several cancers, and its truncated species (ΔImpα3) without the importin-binding domain (IBB), by using fluorescence, circular dichroism (CD), and isothermal titration calorimetry (ITC). Furthermore, the binding of two peptides, encompassing the first and the second NLS regions, was also studied using the same methods and molecular docking simulations. PADI4 interacted with both importin species, with affinity constants of ~1–5 µM. The isolated peptides also interacted with both importins. The molecular simulations predict that the anchoring of both peptides takes place in the major binding site of Impα3 for the NLS of cargo proteins. These findings suggest that both NLS regions were essentially responsible for the binding of PADI4 to the two importin species. Our data are discussed within the framework of a cell mechanism of nuclear transport that is crucial in cancer.
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Neira JL, Palomino-Schätzlein M, Hurtado-Gómez E, Ortore MG, Falcó A. An N-terminal half fragment of the histidine phosphocarrier protein, HPr, is disordered but binds to HPr partners and shows antibacterial properties. Biochim Biophys Acta Gen Subj 2021; 1865:130015. [PMID: 34537288 DOI: 10.1016/j.bbagen.2021.130015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/26/2021] [Accepted: 09/15/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND The phosphotransferase system (PTS) modulates the preferential use of sugars in bacteria. It is formed by a protein cascade in which the first two proteins are general (namely enzyme I, EI, and the histidine phosphocarrier protein, HPr) and the others are sugar-specific permeases; the active site of HPr is His15. The HPr kinase/phosphorylase (HPrK/P), involved in the use of carbon sources in Gram-positive, phopshorylates HPr at a serine. The regulator of sigma D protein (Rsd) also binds to HPr. We are designing specific fragments of HPr, which can be used to interfere with those protein-protein interactions (PPIs), where the intact HPr intervenes. METHODS We obtained a fragment (HPr48) comprising the first forty-eight residues of HPr. HPr48 was disordered as shown by fluorescence, far-ultraviolet (UV) circular dichroism (CD), small angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR). RESULTS Secondary structure propensities, from the assigned backbone nuclei, further support the unfolded nature of the fragment. However, HPr48 was capable of binding to: (i) the N-terminal region of EI, EIN; (ii) the intact Rsd; and, (iii) HPrK/P, as shown by fluorescence, far-UV CD, NMR and biolayer interferometry (BLI). The association constants for each protein, as measured by fluorescence and BLI, were in the order of the low micromolar range, similar to those measured between the intact HPr and each of the other macromolecules. CONCLUSIONS Although HPr48 is forty-eight-residue long, it assisted antibiotics to exert antimicrobial activity. GENERAL SIGNIFICANCE HPr48 could be used as a lead compound in the development of new antibiotics, or, alternatively, to improve the efficiency of existing ones.
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Affiliation(s)
- José L Neira
- IDIBE, Universidad Miguel Hernández, 03202, Elche (Alicante), Spain; Instituto de Biocomputación y Física de Sistemas Complejos (BIFI), Joint Units IQFR-CSIC-BIFI, and GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain.
| | | | | | - María G Ortore
- Dipartimento DiSVA, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Alberto Falcó
- IDIBE, Universidad Miguel Hernández, 03202, Elche (Alicante), Spain.
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