1
|
Banerjee DS, Freedman SL, Murrell MP, Banerjee S. Growth-induced collective bending and kinetic trapping of cytoskeletal filaments. Cytoskeleton (Hoboken) 2024. [PMID: 38775207 DOI: 10.1002/cm.21877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/30/2024] [Accepted: 05/06/2024] [Indexed: 06/04/2024]
Abstract
Growth and turnover of actin filaments play a crucial role in the construction and maintenance of actin networks within cells. Actin filament growth occurs within limited space and finite subunit resources in the actin cortex. To understand how filament growth shapes the emergent architecture of actin networks, we developed a minimal agent-based model coupling filament mechanics and growth in a limiting subunit pool. We find that rapid filament growth induces kinetic trapping of highly bent actin filaments. Such collective bending patterns are long-lived, organized around nematic defects, and arise from competition between filament polymerization and bending elasticity. The stability of nematic defects and the extent of kinetic trapping are amplified by an increase in the abundance of the actin pool and by crosslinking the network. These findings suggest that kinetic trapping is a robust consequence of growth in crowded environments, providing a route to program shape memory in actin networks.
Collapse
Affiliation(s)
- Deb Sankar Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
- James Franck Institute, University of Chicago, Chicago, Illinois, USA
| | | | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Systems Biology Institute, West Haven, Connecticut, USA
- Department of Physics, Yale University, New Haven, Connecticut, USA
| | - Shiladitya Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
2
|
Sun ZG, Yadav V, Amiri S, Cao W, De La Cruz EM, Murrell M. Cofilin-mediated actin filament network flexibility facilitates 2D to 3D actomyosin shape change. Eur J Cell Biol 2024; 103:151379. [PMID: 38168598 DOI: 10.1016/j.ejcb.2023.151379] [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: 08/11/2023] [Revised: 12/06/2023] [Accepted: 12/16/2023] [Indexed: 01/05/2024] Open
Abstract
The organization of actin filaments (F-actin) into crosslinked networks determines the transmission of mechanical stresses within the cytoskeleton and subsequent changes in cell and tissue shape. Principally mediated by proteins such as α-actinin, F-actin crosslinking increases both network connectivity and rigidity, thereby facilitating stress transmission at low crosslinking yet attenuating transmission at high crosslinker concentration. Here, we engineer a two-dimensional model of the actomyosin cytoskeleton, in which myosin-induced mechanical stresses are controlled by light. We alter the extent of F-actin crosslinking by the introduction of oligomerized cofilin. At pH 6.5, F-actin severing by cofilin is weak, but cofilin bundles and crosslinks filaments. Given its effect of lowering the F-actin bending stiffness, cofilin- crosslinked networks are significantly more flexible and softer in bending than networks crosslinked by α-actinin. Thus, upon local activation of myosin-induced contractile stress, the network bends out-of-plane in contrast to the in-plane compression as observed with networks crosslinked by α-actinin. Here, we demonstrate that local effects on filament mechanics by cofilin introduces novel large-scale network material properties that enable the sculpting of complex shapes in the cell cytoskeleton.
Collapse
Affiliation(s)
- Zachary Gao Sun
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA; Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520, USA
| | - Vikrant Yadav
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA
| | - Sorosh Amiri
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Mechanical Engineering and Material Science, Yale University, New Haven, CT 06511, USA
| | - Wenxiang Cao
- Department of Molecular Biology & Biophysics, Yale University, New Haven, CT 06511, USA
| | - Enrique M De La Cruz
- Department of Molecular Biology & Biophysics, Yale University, New Haven, CT 06511, USA
| | - Michael Murrell
- Systems Biology Institute, Yale University, West Haven, CT 06516, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06511, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA; Integrated Graduate Program in Physical and Engineering Biology, Yale University, New Haven, CT 06520, USA.
| |
Collapse
|
3
|
Truglia B, Carbone N, Ghadre I, Vallero S, Zito M, Zizzi EA, Deriu MA, Tuszynski JA. An In Silico Investigation of the Molecular Interactions between Volatile Anesthetics and Actin. Pharmaceuticals (Basel) 2023; 17:37. [PMID: 38256871 PMCID: PMC10819646 DOI: 10.3390/ph17010037] [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: 11/25/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024] Open
Abstract
Volatile anesthetics (VAs) are medicinal chemistry compounds commonly used to enable surgical procedures for patients who undergo painful treatments and can be partially or fully sedated, remaining in an unconscious state during the operation. The specific molecular mechanism of anesthesia is still an open issue, but scientific evidence supports the hypothesis of the involvement of both putative hydrophobic cavities in membrane receptors as binding pockets and interactions between anesthetics and cytoplasmic proteins. Previous studies demonstrated the binding of VAs to tubulin. Since actin is the other major component of the cytoskeleton, this study involves an investigation of its interactions with four major anesthetics: halothane, isoflurane, sevoflurane, and desflurane. Molecular docking was implemented using the Molecular Operating Environment (MOE) software (version 2022.02) and applied to a G-actin monomer, extrapolating the relative binding affinities and root-mean-square deviation (RMSD) values. A comparison with the F-actin was also made to assess if the generally accepted idea about the enhanced F-to-G-actin transformation during anesthesia is warranted. Overall, our results confirm the solvent-like behavior of anesthetics, as evidenced by Van der Waals interactions as well as the relevant hydrogen bonds formed in the case of isoflurane and sevoflurane. Also, a comparison of the interactions of anesthetics with tubulin was made. Finally, the short- and long-term effects of anesthetics are discussed for their possible impact on the occurrence of mental disorders.
Collapse
Affiliation(s)
| | | | | | - Sara Vallero
- DIMEAS, Politecnico di Torino, 10129 Turin, Italy
| | | | | | | | - J. A. Tuszynski
- DIMEAS, Politecnico di Torino, 10129 Turin, Italy
- Department of Data Science and Engineering, The Silesian University of Technology, 44-100 Gliwice, Poland
- Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada
| |
Collapse
|
4
|
Robaszkiewicz K, Wróbel J, Moraczewska J. Troponin and a Myopathy-Linked Mutation in TPM3 Inhibit Cofilin-2-Induced Thin Filament Depolymerization. Int J Mol Sci 2023; 24:16457. [PMID: 38003645 PMCID: PMC10671271 DOI: 10.3390/ijms242216457] [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: 10/18/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/26/2023] Open
Abstract
Uniform actin filament length is required for synchronized contraction of skeletal muscle. In myopathies linked to mutations in tropomyosin (Tpm) genes, irregular thin filaments are a common feature, which may result from defects in length maintenance mechanisms. The current work investigated the effects of the myopathy-causing p.R91C variant in Tpm3.12, a tropomyosin isoform expressed in slow-twitch muscle fibers, on the regulation of actin severing and depolymerization by cofilin-2. The affinity of cofilin-2 for F-actin was not significantly changed by either Tpm3.12 or Tpm3.12-R91C, though it increased two-fold in the presence of troponin (without Ca2+). Saturation of the filament with cofilin-2 removed both Tpm variants from the filament, although Tpm3.12-R91C was more resistant. In the presence of troponin (±Ca2+), Tpm remained on the filament, even at high cofilin-2 concentrations. Both Tpm3.12 variants inhibited filament severing and depolymerization by cofilin-2. However, the inhibition was more efficient in the presence of Tpm3.12-R91C, indicating that the pathogenic variant impaired cofilin-2-dependent actin filament turnover. Troponin (±Ca2+) further inhibited but did not completely stop cofilin-2-dependent actin severing and depolymerization.
Collapse
Affiliation(s)
| | | | - Joanna Moraczewska
- Department of Biochemistry and Cell Biology, Faculty of Biological Sciences, Kazimierz Wielki University in Bydgoszcz, 85-671 Bydgoszcz, Poland; (K.R.); (J.W.)
| |
Collapse
|
5
|
Dinet C, Michelot A. pH gradients guide ADF/cofilin isoforms in pollen tubes. J Cell Biol 2023; 222:e202310012. [PMID: 37824163 PMCID: PMC10568488 DOI: 10.1083/jcb.202310012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023] Open
Abstract
In a recent study, Wang et al. (https://doi.org/10.1083/jcb.202206074) demonstrate that subtle differences between two ADF/cofilin isoforms allow fine spatial regulation of the actin cytoskeleton in pollen tubes. This article illustrates how two similar proteins have progressively evolved to adapt their localization and activity according to the cellular environment.
Collapse
Affiliation(s)
- Céline Dinet
- Aix Marseille University, CNRS, IBDM (UMR 7288), Turing Centre for Living Systems, Marseille, France
| | - Alphée Michelot
- Aix Marseille University, CNRS, IBDM (UMR 7288), Turing Centre for Living Systems, Marseille, France
| |
Collapse
|
6
|
Wang Q, Xu Y, Zhao S, Jiang Y, Yi R, Guo Y, Huang S. Activation of actin-depolymerizing factor by CDPK16-mediated phosphorylation promotes actin turnover in Arabidopsis pollen tubes. PLoS Biol 2023; 21:e3002073. [PMID: 37011088 PMCID: PMC10101649 DOI: 10.1371/journal.pbio.3002073] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/13/2023] [Accepted: 03/11/2023] [Indexed: 04/05/2023] Open
Abstract
As the stimulus-responsive mediator of actin dynamics, actin-depolymerizing factor (ADF)/cofilin is subject to tight regulation. It is well known that kinase-mediated phosphorylation inactivates ADF/cofilin. Here, however, we found that the activity of Arabidopsis ADF7 is enhanced by CDPK16-mediated phosphorylation. We found that CDPK16 interacts with ADF7 both in vitro and in vivo, and it enhances ADF7-mediated actin depolymerization and severing in vitro in a calcium-dependent manner. Accordingly, the rate of actin turnover is reduced in cdpk16 pollen and the amount of actin filaments increases significantly at the tip of cdpk16 pollen tubes. CDPK16 phosphorylates ADF7 at Serine128 both in vitro and in vivo, and the phospho-mimetic mutant ADF7S128D has enhanced actin-depolymerizing activity compared to ADF7. Strikingly, we found that failure in the phosphorylation of ADF7 at Ser128 impairs its function in promoting actin turnover in vivo, which suggests that this phospho-regulation mechanism is biologically significant. Thus, we reveal that CDPK16-mediated phosphorylation up-regulates ADF7 to promote actin turnover in pollen.
Collapse
Affiliation(s)
- Qiannan Wang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanan Xu
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shuangshuang Zhao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
- Key Laboratory of Plant Stress, Life Science College, Shandong Normal University, Jinan, China
| | - Yuxiang Jiang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ran Yi
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| |
Collapse
|
7
|
Liu Q, Ruan H, Sheng Z, Sun X, Li S, Cui W, Li C. Nanoantidote for repression of acidosis pH promoting COVID‐19 infection. VIEW 2022; 3:20220004. [PMID: 35937939 PMCID: PMC9347551 DOI: 10.1002/viw.20220004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 01/08/2023] Open
Abstract
Acidosis, such as respiratory acidosis and metabolic acidosis, can be induced by coronavirus disease 2019 (COVID‐19) infection and is associated with increased mortality in critically ill COVID‐19 patients. It remains unclear whether acidosis further promotes SARS‐CoV‐2 infection in patients, making virus removal difficult. For antacid therapy, sodium bicarbonate poses great risks caused by sodium overload, bicarbonate side effects, and hypocalcemia. Therefore, new antacid antidote is urgently needed. Our study showed that an acidosis‐related pH of 6.8 increases SARS‐CoV‐2 receptor angiotensin‐converting enzyme 2 (ACE2) expression on the cell membrane by regulating intracellular microfilament polymerization, promoting SARS‐CoV‐2 pseudovirus infection. Based on this, we synthesized polyglutamic acid‐PEG materials, used complexation of calcium ions and carboxyl groups to form the core, and adopted biomineralization methods to form a calcium carbonate nanoparticles (CaCO3‐NPs) nanoantidote to neutralize excess hydrogen ions (H+), and restored the pH from 6.8 to approximately 7.4 (normal blood pH). CaCO3‐NPs effectively prevented the heightened SARS‐CoV‐2 infection efficiency due to pH 6.8. Our study reveals that acidosis‐related pH promotes SARS‐CoV‐2 infection, which suggests the existence of a positive feedback loop in which SARS‐CoV‐2 infection‐induced acidosis enhances SARS‐CoV‐2 infection. Therefore, antacid therapy for acidosis COVID‐19 patients is necessary. CaCO3‐NPs may become an effective antacid nanoantidote superior to sodium bicarbonate.
Collapse
Affiliation(s)
- Qidong Liu
- Department of Anesthesiology and Perioperative Medicine Shanghai Fourth People's Hospital, School of Medicine, Tongji University Shanghai P. R. China
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education Orthopedic Department, Tongji Hospital, School of Medicine, Tongji University Shanghai P. R. China
| | - Huitong Ruan
- Department of Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases Shanghai Institute of Traumatology and Orthopaedics Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai P. R. China
| | - Zhihao Sheng
- Department of Anesthesiology Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University Shanghai P. R. China
| | - Xiaoru Sun
- Department of Anesthesiology and Perioperative Medicine Shanghai Fourth People's Hospital, School of Medicine, Tongji University Shanghai P. R. China
| | - Siguang Li
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education Orthopedic Department, Tongji Hospital, School of Medicine, Tongji University Shanghai P. R. China
| | - Wenguo Cui
- Department of Orthopaedics Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases Shanghai Institute of Traumatology and Orthopaedics Ruijin Hospital Shanghai Jiao Tong University School of Medicine Shanghai P. R. China
| | - Cheng Li
- Department of Anesthesiology and Perioperative Medicine Shanghai Fourth People's Hospital, School of Medicine, Tongji University Shanghai P. R. China
| |
Collapse
|
8
|
Sun J, Zhong X, Fu X, Miller H, Lee P, Yu B, Liu C. The Actin Regulators Involved in the Function and Related Diseases of Lymphocytes. Front Immunol 2022; 13:799309. [PMID: 35371070 PMCID: PMC8965893 DOI: 10.3389/fimmu.2022.799309] [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: 10/21/2021] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Actin is an important cytoskeletal protein involved in signal transduction, cell structure and motility. Actin regulators include actin-monomer-binding proteins, Wiskott-Aldrich syndrome (WAS) family of proteins, nucleation proteins, actin filament polymerases and severing proteins. This group of proteins regulate the dynamic changes in actin assembly/disassembly, thus playing an important role in cell motility, intracellular transport, cell division and other basic cellular activities. Lymphocytes are important components of the human immune system, consisting of T-lymphocytes (T cells), B-lymphocytes (B cells) and natural killer cells (NK cells). Lymphocytes are indispensable for both innate and adaptive immunity and cannot function normally without various actin regulators. In this review, we first briefly introduce the structure and fundamental functions of a variety of well-known and newly discovered actin regulators, then we highlight the role of actin regulators in T cell, B cell and NK cell, and finally provide a landscape of various diseases associated with them. This review provides new directions in exploring actin regulators and promotes more precise and effective treatments for related diseases.
Collapse
Affiliation(s)
- Jianxuan Sun
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department and Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xingyu Zhong
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Fu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heather Miller
- Cytek Biosciences, R&D Clinical Reagents, Fremont, CA, United States
| | - Pamela Lee
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Bing Yu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohong Liu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
9
|
Chen X, Chen Y, Wang C, Jiang Y, Chu X, Wu F, Wu Y, Cai X, Cao Y, Liu Y, Bu W. NIR‐Triggered Intracellular H
+
Transients for Lamellipodia‐Collapsed Antimetastasis and Enhanced Chemodynamic Therapy. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107588] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Xiaoyan Chen
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Shanghai 200062 P. R. China
- Department of Materials Science Fudan University Shanghai 200433 P. R. China
| | - Yang Chen
- Tongji University Cancer Center Shanghai Tenth People's Hospital Tongji University School of Medicine Shanghai 200072 P. R. China
| | - Chaochao Wang
- Tongji University Cancer Center Shanghai Tenth People's Hospital Tongji University School of Medicine Shanghai 200072 P. R. China
| | - Yaqin Jiang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Shanghai 200062 P. R. China
- Department of Materials Science Fudan University Shanghai 200433 P. R. China
| | - Xu Chu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Shanghai 200062 P. R. China
- Department of Materials Science Fudan University Shanghai 200433 P. R. China
| | - Fan Wu
- Tongji University Cancer Center Shanghai Tenth People's Hospital Tongji University School of Medicine Shanghai 200072 P. R. China
| | - Yelin Wu
- Tongji University Cancer Center Shanghai Tenth People's Hospital Tongji University School of Medicine Shanghai 200072 P. R. China
| | - Xuechao Cai
- Tongji University Cancer Center Shanghai Tenth People's Hospital Tongji University School of Medicine Shanghai 200072 P. R. China
| | - Yi Cao
- Department of Plastic and Reconstructive Surgery Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai 200011 P. R. China
| | - Yanyan Liu
- Department of Materials Science Fudan University Shanghai 200433 P. R. China
| | - Wenbo Bu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes School of Chemistry and Molecular Engineering East China Normal University Shanghai 200062 P. R. China
- Department of Materials Science Fudan University Shanghai 200433 P. R. China
| |
Collapse
|
10
|
Chen X, Chen Y, Wang C, Jiang Y, Chu X, Wu F, Wu Y, Cai X, Cao Y, Liu Y, Bu W. NIR-Triggered Intracellular H + Transients for Lamellipodia-Collapsed Antimetastasis and Enhanced Chemodynamic Therapy. Angew Chem Int Ed Engl 2021; 60:21905-21910. [PMID: 34322970 DOI: 10.1002/anie.202107588] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/15/2021] [Indexed: 12/22/2022]
Abstract
In solid tumors, tumor invasion and metastasis account for 90 % of cancer-related deaths. Cell migration is steered by the lamellipodia formed at the leading edge. These lamellipodia can drive the cell body forward by its mechanical deformation regulated by cofilin. Inhibiting cofilin activity can cause significant defects in directional lamellipodia formation and the locomotory capacity of cell invasion, thus contributing to antimetastatic treatment. Herein, a near infrared light (NIR)-controlled nanoscale proton supplier was designed with upconversion nanoparticles (UCNPs) as a core coated in MIL-88B for interior photoacids loading; this photoacids loading can boost H+ transients in cells, which converts the cofilin to an inactive form. Strikingly, inactive cofilin loses the ability to mediate lamellipodia deformation for cell migration. Additionally, the iron, which serves as a catalyticaly active center in MIL-88B, initiates an enhanced Fenton reaction due to the increased H+ in the tumor, ultimately achieving intensive chemodynamic therapy (CDT). This work provides new insight into H+ transients in cells, which not only regulates cofilin protonation for antimetastatic treatment but also improves chemodynamic therapy.
Collapse
Affiliation(s)
- Xiaoyan Chen
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China.,Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Yang Chen
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Chaochao Wang
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Yaqin Jiang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China.,Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Xu Chu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China.,Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Fan Wu
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Yelin Wu
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Xuechao Cai
- Tongji University Cancer Center, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Yi Cao
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, P. R. China
| | - Yanyan Liu
- Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Wenbo Bu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, P. R. China.,Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| |
Collapse
|
11
|
Hayashi M, Palmgren M. The quest for the central players governing pollen tube growth and guidance. PLANT PHYSIOLOGY 2021; 185:682-693. [PMID: 33793904 PMCID: PMC8133568 DOI: 10.1093/plphys/kiaa092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 12/06/2020] [Indexed: 05/02/2023]
Abstract
Recent insights into the mechanism of pollen tube growth and guidance point to the importance of H+ dynamics, which are regulated by the plasma membrane H+-ATPase.
Collapse
Affiliation(s)
- Maki Hayashi
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, Copenhagen, Denmark
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000,China
- Author for communication:
| |
Collapse
|
12
|
Lou SS, Kennard AS, Koslover EF, Gutierrez E, Groisman A, Theriot JA. Elastic wrinkling of keratocyte lamellipodia driven by myosin-induced contractile stress. Biophys J 2021; 120:1578-1591. [PMID: 33631203 DOI: 10.1016/j.bpj.2021.02.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 11/16/2022] Open
Abstract
During actin-based cell migration, the actin cytoskeleton in the lamellipodium both generates and responds to force, which has functional consequences for the ability of the cell to extend protrusions. However, the material properties of the lamellipodial actin network and its response to stress on the timescale of motility are incompletely understood. Here, we describe a dynamic wrinkling phenotype in the lamellipodium of fish keratocytes, in which the actin sheet buckles upward away from the ventral membrane of the cell, forming a periodic pattern of wrinkles perpendicular to the cell's leading edge. Cells maintain an approximately constant wrinkle wavelength over time despite new wrinkle formation and the lateral movement of wrinkles in the cell frame of reference, suggesting that cells have a preferred or characteristic wrinkle wavelength. Generation of wrinkles is dependent upon myosin contractility, and their wavelength scales directly with the density of the actin network and inversely with cell adhesion. These results are consistent with a simple physical model for wrinkling in an elastic sheet under compression and suggest that the lamellipodial cytoskeleton behaves as an elastic material on the timescale of cell migration despite rapid actin turnover.
Collapse
Affiliation(s)
- Sunny S Lou
- Department of Chemical and Systems Biology, Stanford University, Stanford, California
| | - Andrew S Kennard
- Program in Biophysics, Stanford University, Stanford, California; Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, Washington
| | - Elena F Koslover
- Department of Physics, University of California, San Diego, San Diego, California
| | - Edgar Gutierrez
- Department of Physics, University of California, San Diego, San Diego, California
| | - Alexander Groisman
- Department of Physics, University of California, San Diego, San Diego, California
| | - Julie A Theriot
- Department of Biology and Howard Hughes Medical Institute, University of Washington, Seattle, Washington.
| |
Collapse
|
13
|
Tang VW, Nadkarni AV, Brieher WM. Catastrophic actin filament bursting by cofilin, Aip1, and coronin. J Biol Chem 2020; 295:13299-13313. [PMID: 32723865 DOI: 10.1074/jbc.ra120.015018] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/24/2020] [Indexed: 11/06/2022] Open
Abstract
Cofilin is an actin filament severing protein necessary for fast actin turnover dynamics. Coronin and Aip1 promote cofilin-mediated actin filament disassembly, but the mechanism is somewhat controversial. An early model proposed that the combination of cofilin, coronin, and Aip1 disassembled filaments in bursts. A subsequent study only reported severing. Here, we used EM to show that actin filaments convert directly into globular material. A monomer trap assay also shows that the combination of all three factors produces actin monomers faster than any two factors alone. We show that coronin accelerates the release of Pi from actin filaments and promotes highly cooperative cofilin binding to actin to create long stretches of polymer with a hypertwisted morphology. Aip1 attacks these hypertwisted regions along their sides, disintegrating them into monomers or short oligomers. The results are consistent with a catastrophic mode of disassembly, not enhanced severing alone.
Collapse
Affiliation(s)
- Vivian W Tang
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
| | - Ambika V Nadkarni
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA
| | - William M Brieher
- Department of Cell and Developmental Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois, USA.
| |
Collapse
|
14
|
Hoffmann RD, Portes MT, Olsen LI, Damineli DSC, Hayashi M, Nunes CO, Pedersen JT, Lima PT, Campos C, Feijó JA, Palmgren M. Plasma membrane H +-ATPases sustain pollen tube growth and fertilization. Nat Commun 2020; 11:2395. [PMID: 32409656 PMCID: PMC7224221 DOI: 10.1038/s41467-020-16253-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 04/23/2020] [Indexed: 01/18/2023] Open
Abstract
Pollen tubes are highly polarized tip-growing cells that depend on cytosolic pH gradients for signaling and growth. Autoinhibited plasma membrane proton (H+) ATPases (AHAs) have been proposed to energize pollen tube growth and underlie cell polarity, however, mechanistic evidence for this is lacking. Here we report that the combined loss of AHA6, AHA8, and AHA9 in Arabidopsis thaliana delays pollen germination and causes pollen tube growth defects, leading to drastically reduced fertility. Pollen tubes of aha mutants had reduced extracellular proton (H+) and anion fluxes, reduced cytosolic pH, reduced tip-to-shank proton gradients, and defects in actin organization. Furthermore, mutant pollen tubes had less negative membrane potentials, substantiating a mechanistic role for AHAs in pollen tube growth through plasma membrane hyperpolarization. Our findings define AHAs as energy transducers that sustain the ionic circuit defining the spatial and temporal profiles of cytosolic pH, thereby controlling downstream pH-dependent mechanisms essential for pollen tube elongation, and thus plant fertility.
Collapse
Affiliation(s)
- Robert D Hoffmann
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Maria Teresa Portes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Lene Irene Olsen
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Daniel Santa Cruz Damineli
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo, São Paulo, SP, 01246-903, Brazil
| | - Maki Hayashi
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Custódio O Nunes
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Jesper T Pedersen
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark
| | - Pedro T Lima
- Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal
| | - Cláudia Campos
- Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
- Instituto Gulbenkian de Ciência, Oeiras, 2780-156, Portugal.
| | - Michael Palmgren
- Department for Plant and Environmental Sciences, University of Copenhagen, 1871, Frederiksberg C, Denmark.
| |
Collapse
|
15
|
Long-Range and Directional Allostery of Actin Filaments Plays Important Roles in Various Cellular Activities. Int J Mol Sci 2020; 21:ijms21093209. [PMID: 32370032 PMCID: PMC7246755 DOI: 10.3390/ijms21093209] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 12/18/2022] Open
Abstract
A wide variety of uniquely localized actin-binding proteins (ABPs) are involved in various cellular activities, such as cytokinesis, migration, adhesion, morphogenesis, and intracellular transport. In a micrometer-scale space such as the inside of cells, protein molecules diffuse throughout the cell interior within seconds. In this condition, how can ABPs selectively bind to particular actin filaments when there is an abundance of actin filaments in the cytoplasm? In recent years, several ABPs have been reported to induce cooperative conformational changes to actin filaments allowing structural changes to propagate along the filament cables uni- or bidirectionally, thereby regulating the subsequent binding of ABPs. Such propagation of ABP-induced cooperative conformational changes in actin filaments may be advantageous for the elaborate regulation of cellular activities driven by actin-based machineries in the intracellular space, which is dominated by diffusion. In this review, we focus on long-range allosteric regulation driven by cooperative conformational changes of actin filaments that are evoked by binding of ABPs, and discuss roles of allostery of actin filaments in narrow intracellular spaces.
Collapse
|
16
|
Sin WC, Tam N, Moniz D, Lee C, Church J. Na/H exchanger NHE1 acts upstream of rho GTPases to promote neurite outgrowth. J Cell Commun Signal 2020; 14:325-333. [PMID: 32144636 DOI: 10.1007/s12079-020-00556-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/28/2020] [Indexed: 02/05/2023] Open
Abstract
Na+/H+ exchanger NHE1, a major determinant of intracellular pH (pHi) in mammalian central neurons, promotes neurite outgrowth under both basal and netrin-1-stimulated conditions. The small GTP binding proteins and their effectors have a dominant role in netrin-1-stimulated neurite outgrowth. Since NHE1 has been shown previously to work downstream of the Rho GTPases-mediated polarized membrane protrusion in non-neuronal cells, we examined whether NHE1 has a similar relationship with Cdc42, Rac1 and RhoA in neuronal morphogenesis. Interestingly, our results suggest the possibility that NHE1 acting upstream of Rho GTPases to promote neurite outgrowth induced by netrin-1. First, we found that netrin-1-induced increases in the activities of Rho GTPases using FRET (Forster Resonance Energy Transfer) analyses in individual growth cones; furthermore, their increased activities were abolished by cariporide, a specific NHE1 inhibitor. Second, NHE1 inhibition had no effect on neurite retraction induced by L-α-Lysophosphatidic acid (LPA), a potent RhoA activator. The regulation of Rho GTPases by NHE1 was further evidenced by reduced Rac1, Cdc42 and RhoA activities in NHE1-null neurons. Taken together, our findings suggest that NHE1-dependent neuronal morphogenesis involves the activation of Rho-family of small GTPases.
Collapse
Affiliation(s)
- Wun Chey Sin
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada.
| | - Nicola Tam
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - David Moniz
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Connie Lee
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - John Church
- Department of Cellular and Physiological Sciences, Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
17
|
Merino F, Pospich S, Raunser S. Towards a structural understanding of the remodeling of the actin cytoskeleton. Semin Cell Dev Biol 2019; 102:51-64. [PMID: 31836290 PMCID: PMC7221352 DOI: 10.1016/j.semcdb.2019.11.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/27/2019] [Accepted: 11/28/2019] [Indexed: 12/03/2022]
Abstract
Actin filaments (F-actin) are a key component of eukaryotic cells. Whether serving as a scaffold for myosin or using their polymerization to push onto cellular components, their function is always related to force generation. To control and fine-tune force production, cells have a large array of actin-binding proteins (ABPs) dedicated to control every aspect of actin polymerization, filament localization, and their overall mechanical properties. Although great advances have been made in our biochemical understanding of the remodeling of the actin cytoskeleton, the structural basis of this process is still being deciphered. In this review, we summarize our current understanding of this process. We outline how ABPs control the nucleation and disassembly, and how these processes are affected by the nucleotide state of the filaments. In addition, we highlight recent advances in the understanding of actomyosin force generation, and describe recent advances brought forward by the developments of electron cryomicroscopy.
Collapse
Affiliation(s)
- Felipe Merino
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Sabrina Pospich
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Stefan Raunser
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
| |
Collapse
|
18
|
Shekhar S, Chung J, Kondev J, Gelles J, Goode BL. Synergy between Cyclase-associated protein and Cofilin accelerates actin filament depolymerization by two orders of magnitude. Nat Commun 2019; 10:5319. [PMID: 31757952 PMCID: PMC6876572 DOI: 10.1038/s41467-019-13268-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/29/2019] [Indexed: 11/29/2022] Open
Abstract
Cellular actin networks can be rapidly disassembled and remodeled in a few seconds, yet in vitro actin filaments depolymerize slowly over minutes. The cellular mechanisms enabling actin to depolymerize this fast have so far remained obscure. Using microfluidics-assisted TIRF, we show that Cyclase-associated protein (CAP) and Cofilin synergize to processively depolymerize actin filament pointed ends at a rate 330-fold faster than spontaneous depolymerization. Single molecule imaging further reveals that hexameric CAP molecules interact with the pointed ends of Cofilin-decorated filaments for several seconds at a time, removing approximately 100 actin subunits per binding event. These findings establish a paradigm, in which a filament end-binding protein and a side-binding protein work in concert to control actin dynamics, and help explain how rapid actin network depolymerization is achieved in cells.
Collapse
Affiliation(s)
- Shashank Shekhar
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA
| | - Johnson Chung
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA, 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, Waltham, MA, 02454, USA.
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA, 02454, USA.
| |
Collapse
|
19
|
Wioland H, Jegou A, Romet-Lemonne G. Quantitative Variations with pH of Actin Depolymerizing Factor/Cofilin's Multiple Actions on Actin Filaments. Biochemistry 2018; 58:40-47. [PMID: 30499293 PMCID: PMC6358128 DOI: 10.1021/acs.biochem.8b01001] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
![]()
Actin
depolymerizing factor (ADF)/cofilin is the main protein family
promoting the disassembly of actin filaments, which is essential for
numerous cellular functions. ADF/cofilin proteins disassemble actin
filaments through different reactions, as they bind to their sides,
sever them, and promote the depolymerization of the resulting ADF/cofilin-saturated
filaments. Moreover, the efficiency of ADF/cofilin is known to be
very sensitive to pH. ADF/cofilin thus illustrates two challenges
in actin biochemistry: separating the different regulatory actions
of a single protein and characterizing them as a function of specific
biochemical conditions. Here, we investigate the different reactions
of ADF/cofilin on actin filaments, at four different pH values ranging
from 6.6 to 7.8, using single-filament microfluidics techniques. We
show that decreasing the pH decreases the effective filament severing
rate by increasing the rate at which filaments become saturated by
ADF/cofilin, thereby reducing the number of ADF/cofilin domain boundaries,
where severing can occur. The severing rate per domain boundary, however,
remains unchanged at different pH values. The ADF/cofilin-decorated
filaments (“cofilactin” filaments) depolymerize from
both ends. We show here that, at physiological pH (7.0–7.4),
the pointed end depolymerization of cofilactin filaments is barely
faster than that of bare filaments. In contrast, cofilactin barbed
ends undergo an “unstoppable” depolymerization (depolymerizing
for minutes despite the presence of free actin monomers and capping
protein in solution), throughout our pH range. We thus show that,
at physiological pH, the main contribution of ADF/cofilin to filament
depolymerization is at the barbed end.
Collapse
Affiliation(s)
- Hugo Wioland
- Institut Jacques Monod, CNRS, Université Paris-Diderot , 75013 Paris , France
| | - Antoine Jegou
- Institut Jacques Monod, CNRS, Université Paris-Diderot , 75013 Paris , France
| | | |
Collapse
|
20
|
Baroni L, Pereira LM, Maciver SK, Yatsuda AP. Functional characterisation of the actin-depolymerising factor from the apicomplexan Neospora caninum (NcADF). Mol Biochem Parasitol 2018; 224:26-36. [PMID: 30040977 DOI: 10.1016/j.molbiopara.2018.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/15/2018] [Accepted: 07/15/2018] [Indexed: 01/20/2023]
Abstract
Neospora caninum is an apicomplexan parasite that causes infectious abortion in cows. As an obligate intracellular parasite, N. caninum requires a host cell environment to survive and replicate. The locomotion and invasion mechanisms of apicomplexan parasites are centred on the actin-myosin system to propel the parasite forwards and into the host cell. The functions of actin, an intrinsically dynamic protein, are modulated by actin-binding proteins (ABPs). Actin-depolymerising factor (ADF) is a ubiquitous ABP responsible for accelerating actin turnover in eukaryotic cells and is one of the few known conserved ABPs from apicomplexan parasites. Apicomplexan ADFs have nonconventional properties compared with ADF/cofilins from higher eukaryotes. In the present paper, we characterised the ADF from N. caninum (NcADF) using computational and in vitro biochemical approaches to investigate its function in rabbit muscle actin dynamics. Our predicted computational tertiary structure of NcADF demonstrated a conserved structure and phylogeny with respect to other ADF/cofilins, although certain differences in filamentous actin (F-actin) binding sites were present. The activity of recombinant NcADF on heterologous actin was regulated in part by pH and the presence of inorganic phosphate. In addition, our data suggest a comparatively weak disassembly of F-actin by NcADF. Taken together, the data presented herein represent a contribution to the field towards the understanding of the role of ADF in N. caninum and a comparative analysis of ABPs in the phylum Apicomplexa.
Collapse
Affiliation(s)
- Luciana Baroni
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil
| | - Luiz M Pereira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil
| | - Sutherland K Maciver
- Centre for Discovery Brain Sciences, Biomedical Sciences, Edinburgh Medical School, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, Scotland, United Kingdom
| | - Ana P Yatsuda
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-930, Ribeirão Preto, SP, Brazil.
| |
Collapse
|
21
|
Hilton DM, Aguilar RM, Johnston AB, Goode BL. Species-Specific Functions of Twinfilin in Actin Filament Depolymerization. J Mol Biol 2018; 430:3323-3336. [PMID: 29928893 DOI: 10.1016/j.jmb.2018.06.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022]
Abstract
Twinfilin is a highly conserved member of the actin depolymerization factor homology (ADF-H) protein superfamily, which also includes ADF/Cofilin, Abp1/Drebrin, GMF, and Coactosin. Twinfilin has a unique molecular architecture consisting of two ADF-H domains joined by a linker and followed by a C-terminal tail. Yeast Twinfilin, in conjunction with yeast cyclase-associated protein (Srv2/CAP), increases the rate of depolymerization at both the barbed and pointed ends of actin filaments. However, it has remained unclear whether these activities extend to Twinfilin homologs in other species. To address this, we purified the three mouse Twinfilin isoforms (mTwf1, mTwf2a, mTwf2b) and mouse CAP1, and used total internal reflection fluorescence microscopy assays to study their effects on filament disassembly. Our results show that all three mouse Twinfilin isoforms accelerate barbed end depolymerization similar to yeast Twinfilin, suggesting that this activity is evolutionarily conserved. In striking contrast, mouse Twinfilin isoforms and CAP1 failed to induce rapid pointed end depolymerization. Using chimeras, we show that the yeast-specific pointed end depolymerization activity is specified by the C-terminal ADF-H domain of yeast Twinfilin. In addition, Tropomyosin decoration of filaments failed to impede depolymerization by yeast and mouse Twinfilin and Srv2/CAP, but inhibited Cofilin severing. Together, our results indicate that Twinfilin has conserved functions in regulating barbed end dynamics, although its ability to drive rapid pointed end depolymerization appears to be species-specific. We discuss the implications of this work, including that pointed end depolymerization may be catalyzed by different ADF-H family members in different species.
Collapse
Affiliation(s)
- Denise M Hilton
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Rey M Aguilar
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Adam B Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA.
| |
Collapse
|
22
|
Helical rotation of the diaphanous-related formin mDia1 generates actin filaments resistant to cofilin. Proc Natl Acad Sci U S A 2018; 115:E5000-E5007. [PMID: 29760064 PMCID: PMC5984536 DOI: 10.1073/pnas.1803415115] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The complex interplay between actin regulatory proteins facilitates the formation of diverse cellular actin structures. Formin homology proteins (formins) play an essential role in the formation of actin stress fibers and yeast actin cables, to which the major actin depolymerizing factor cofilin barely associates. In vitro, F-actin decorated with cofilin exhibits a marked increase in the filament twist. On the other hand, a mammalian formin mDia1 rotates along the long-pitch actin helix during processive actin elongation (helical rotation). Helical rotation may impose torsional force on F-actin in the opposite direction of the cofilin-induced twisting. Here, we show that helical rotation of mDia1 converts F-actin resistant to cofilin both in vivo and in vitro. F-actin assembled by mDia1 without rotational freedom became more resistant to the severing and binding activities of cofilin than freely rotatable F-actin. Electron micrographic analysis revealed untwisting of the long-pitch helix of F-actin elongating from mDia1 on tethering of both mDia1 and the pointed end side of the filament. In cells, single molecules of mDia1ΔC63, an activated mutant containing N-terminal regulatory domains, showed tethering to cell structures more frequently than autoinhibited wild-type mDia1 and mDia1 devoid of N-terminal domains. Overexpression of mDia1ΔC63 induced the formation of F-actin, which has prolonged lifetime and accelerates dissociation of cofilin. Helical rotation of formins may thus serve as an F-actin stabilizing mechanism by which a barbed end-bound molecule can enhance the stability of a filament over a long range.
Collapse
|
23
|
Structure, dynamics, and biochemical characterization of ADF/cofilin Twinstar from Drosophilamelanogaster. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:885-898. [PMID: 29709602 DOI: 10.1016/j.bbapap.2018.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Twinstar is an ADF/cofilin family protein, which is expressed by the tsr gene in Drosophila melanogaster. Twinstar is one of the main regulators of actin cytoskeleton remodelling and is essential for vital cellular processes like cytokinesis and endocytosis. METHODS We have characterized the structure and dynamics of Twinstar by solution NMR spectroscopy, the interaction of Twinstar with rabbit muscle actin by ITC, and biochemical activities of Twinstar through different biochemical assays using fluorescence spectroscopy and ultra-centrifugation. RESULTS The solution structure of Twinstar shows characteristic ADF-H fold with well-formed G/F-site and F-site for interaction with actin. The structure possesses an extended F-loop, which is rigid at the base, but flexible towards its apical region. Twinstar shares similar dynamics for the G/F-site with C. elegans homologs, UNC-60A and UNC-60B. However, the dynamics of its F-loop are different from its C. elegans homologs. Twinstar shows strong affinity for ADP-G-Actin and ATP-G-Actin with Kds of ~7.6 nM and ~0.4 μM, respectively. It shows mild F-actin depolymerizing activity and stable interaction with F-actin with a Kd of ~5.0 μM. It inhibits the rate of the nucleotide exchange in a dose dependent manner. CONCLUSION On the basis of structure, dynamics, and biochemical activity, Twinstar can be taken to execute its biochemical role by facilitating directional growth and maintenance of length of actin filaments. GENERAL SIGNIFICANCE This study characterizes the structure, backbone dynamics, and biochemical activities of Twinstar of Drosophila, which provides an insight into the regulation of actin dynamics in the member of phylum insecta.
Collapse
|
24
|
Maffioli E, Schulte C, Nonnis S, Grassi Scalvini F, Piazzoni C, Lenardi C, Negri A, Milani P, Tedeschi G. Proteomic Dissection of Nanotopography-Sensitive Mechanotransductive Signaling Hubs that Foster Neuronal Differentiation in PC12 Cells. Front Cell Neurosci 2018; 11:417. [PMID: 29354032 PMCID: PMC5758595 DOI: 10.3389/fncel.2017.00417] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/12/2017] [Indexed: 12/11/2022] Open
Abstract
Neuronal cells are competent in precisely sensing nanotopographical features of their microenvironment. The perceived microenvironmental information will be “interpreted” by mechanotransductive processes and impacts on neuronal functioning and differentiation. Attempts to influence neuronal differentiation by engineering substrates that mimic appropriate extracellular matrix (ECM) topographies are hampered by the fact that profound details of mechanosensing/-transduction complexity remain elusive. Introducing omics methods into these biomaterial approaches has the potential to provide a deeper insight into the molecular processes and signaling cascades underlying mechanosensing/-transduction but their exigence in cellular material is often opposed by technical limitations of major substrate top-down fabrication methods. Supersonic cluster beam deposition (SCBD) allows instead the bottom-up fabrication of nanostructured substrates over large areas characterized by a quantitatively controllable ECM-like nanoroughness that has been recently shown to foster neuron differentiation and maturation. Exploiting this capacity of SCBD, we challenged mechanosensing/-transduction and differentiative behavior of neuron-like PC12 cells with diverse nanotopographies and/or changes of their biomechanical status, and analyzed their phosphoproteomic profiles in these settings. Versatile proteins that can be associated to significant processes along the mechanotransductive signal sequence, i.e., cell/cell interaction, glycocalyx and ECM, membrane/f-actin linkage and integrin activation, cell/substrate interaction, integrin adhesion complex, actomyosin organization/cellular mechanics, nuclear organization, and transcriptional regulation, were affected. The phosphoproteomic data suggested furthermore an involvement of ILK, mTOR, Wnt, and calcium signaling in these nanotopography- and/or cell mechanics-related processes. Altogether, potential nanotopography-sensitive mechanotransductive signaling hubs participating in neuronal differentiation were dissected.
Collapse
Affiliation(s)
- Elisa Maffioli
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy
| | - Carsten Schulte
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Simona Nonnis
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Francesca Grassi Scalvini
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Claudio Piazzoni
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Cristina Lenardi
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Armando Negri
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| | - Paolo Milani
- Centre for Nanostructured Materials and Interfaces, Università degli Studi di Milano, Milan, Italy
| | - Gabriella Tedeschi
- Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy.,Fondazione Filarete, Milan, Italy
| |
Collapse
|
25
|
Identification of biomarkers for childhood obesity based on expressional correlation and functional similarity. Mol Med Rep 2017; 17:109-116. [PMID: 29115457 PMCID: PMC5780071 DOI: 10.3892/mmr.2017.7913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 02/11/2016] [Indexed: 12/13/2022] Open
Abstract
The aim of the current study was to identify potential biomarkers of childhood obesity, and investigate molecular mechanisms and candidate agents in order to improve therapeutic strategies for childhood obesity. The GSE9624 gene expression profile was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) in omental adipose tissues were analyzed with limma package by comparing samples from obese and normal control children. Two-way hierarchical clustering was applied using the pheatmap package. The co-expression (CE) analysis was performed using online CoExpress software. Subsequent to functional classification via the GOSim package, the gene network enriched by DEGs was visualized using the Cytoscape package. The codon usage bias of the DEGs was then examined using the CAI program from the European Molecular Biology Open Software Suite. In total, 583 DEGs (273 upregulated genes and 310 downregulated genes) were observed in the omental adipose tissues between samples from obese and normal control children. Hierarchical clustering identified a significant difference between samples from obese and normal control children. Subsequent to CE analysis, 130 DEGs, which were classified into 4 clusters, were selected. The following 3 upregulated and 2 downregulated genes were identified to be significant: Upregulated genes, microtubule-associated protein tau (MAPT), destrin (actin depolymerizing factor) (DSTN) and spectrin, β, non-erythrocytic 1 (SPTBN1); downregulated genes, Rho/Rac guanine nucleotide exchange factor 2 (ARHGEF2) and spindle and kinetochore associated complex subunit 1 (SKA1). The top 3 amino acids were identified to be glycine, leucine and serine with a high bias. The DEGs MAPT, DSTN, SPTBN1, ARHGEF2 and SKA1 are suggested to be candidate biomarkers for childhood obesity.
Collapse
|
26
|
Functions of actin-interacting protein 1 (AIP1)/WD repeat protein 1 (WDR1) in actin filament dynamics and cytoskeletal regulation. Biochem Biophys Res Commun 2017; 506:315-322. [PMID: 29056508 DOI: 10.1016/j.bbrc.2017.10.096] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 10/18/2017] [Indexed: 02/04/2023]
Abstract
Actin-depolymerizing factor (ADF)/cofilin and actin-interacting protein 1 (AIP1), also known as WD-repeat protein 1 (WDR1), are conserved among eukaryotes and play critical roles in dynamic reorganization of the actin cytoskeleton. AIP1 preferentially promotes disassembly of ADF/cofilin-decorated actin filaments but exhibits minimal effects on bare actin filaments. Therefore, AIP1 has been often considered to be an ancillary co-factor of ADF/cofilin that merely boosts ADF/cofilin activity level. However, genetic and cell biological studies show that AIP1 deficiency often causes lethality or severe abnormalities in multiple tissues and organs including muscle, epithelia, and blood, suggesting that AIP1 is a major regulator of many biological processes that depend on actin dynamics. This review summarizes recent progress in studies on the biochemical mechanism of actin filament severing by AIP1 and in vivo functions of AIP1 in model organisms and human diseases.
Collapse
|
27
|
Biochemistry of Drebrin and Its Binding to Actin Filaments. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:37-47. [DOI: 10.1007/978-4-431-56550-5_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
|
28
|
Iwase S, Ono S. Conserved hydrophobic residues in the CARP/β-sheet domain of cyclase-associated protein are involved in actin monomer regulation. Cytoskeleton (Hoboken) 2017; 74:343-355. [PMID: 28696540 DOI: 10.1002/cm.21385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/05/2017] [Accepted: 07/07/2017] [Indexed: 01/12/2023]
Abstract
Cyclase-associated protein (CAP) is a multidomain protein that promotes actin filament dynamics. The C-terminal region of CAP contains a CAP and X-linked retinitis pigmentosa 2 protein (CARP) domain (or a β-sheet domain), which binds to actin monomer and is essential for enhancing exchange of actin-bound nucleotides. However, how the CARP domain binds to actin is not clearly understood. Here, we report that conserved hydrophobic residues in the CARP domain play important roles in the function of CAP to regulate actin dynamics. Single mutations of three conserved surface-exposed hydrophobic residues in the CARP domain of CAS-2, a Caenorhabditis elegans CAP, significantly reduce its binding to actin monomers and suppress its nucleotide exchange activity on actin. As a result, these mutants are weaker than wild-type to compete with ADF/cofilin to promote recycling of actin monomers for polymerization. A double mutation (V367A/I373A) eliminates these actin-regulatory functions of CAS-2. These hydrophobic residues and previously identified functional residues are scattered on a concave β-sheet of the CARP domain, suggesting that a wide area of the β-sheet is involved in binding to actin. These observations suggest that the CARP domain of CAP binds to actin in a distinct manner from other known actin-binding proteins.
Collapse
Affiliation(s)
- Shohei Iwase
- Department of Pathology, Winship Cancer Institute, Emory University, Atlanta, Georgia.,Department of Cell Biology, Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Shoichiro Ono
- Department of Pathology, Winship Cancer Institute, Emory University, Atlanta, Georgia.,Department of Cell Biology, Winship Cancer Institute, Emory University, Atlanta, Georgia
| |
Collapse
|
29
|
Carlier MF, Shekhar S. Global treadmilling coordinates actin turnover and controls the size of actin networks. Nat Rev Mol Cell Biol 2017; 18:389-401. [DOI: 10.1038/nrm.2016.172] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
30
|
Mumtaz R, Trepiccione F, Hennings JC, Huebner AK, Serbin B, Picard N, Ullah AKMS, Păunescu TG, Capen DE, Lashhab RM, Mouro-Chanteloup I, Alper SL, Wagner CA, Cordat E, Brown D, Eladari D, Hübner CA. Intercalated Cell Depletion and Vacuolar H +-ATPase Mistargeting in an Ae1 R607H Knockin Model. J Am Soc Nephrol 2016; 28:1507-1520. [PMID: 27932475 DOI: 10.1681/asn.2016020169] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 11/08/2016] [Indexed: 12/27/2022] Open
Abstract
Distal nephron acid secretion is mediated by highly specialized type A intercalated cells (A-ICs), which contain vacuolar H+-ATPase (V-type ATPase)-rich vesicles that fuse with the apical plasma membrane on demand. Intracellular bicarbonate generated by luminal H+ secretion is removed by the basolateral anion-exchanger AE1. Chronically reduced renal acid excretion in distal renal tubular acidosis (dRTA) may lead to nephrocalcinosis and renal failure. Studies in MDCK monolayers led to the proposal of a dominant-negative trafficking mechanism to explain AE1-associated dominant dRTA. To test this hypothesis in vivo, we generated an Ae1 R607H knockin mouse, which corresponds to the most common dominant dRTA mutation in human AE1, R589H. Compared with wild-type mice, heterozygous and homozygous R607H knockin mice displayed incomplete dRTA characterized by compensatory upregulation of the Na+/HCO3- cotransporter NBCn1. Red blood cell Ae1-mediated anion-exchange activity and surface polypeptide expression did not change. Mutant mice expressed far less Ae1 in A-ICs, but basolateral targeting of the mutant protein was preserved. Notably, mutant mice also exhibited reduced expression of V-type ATPase and compromised targeting of this proton pump to the plasma membrane upon acid challenge. Accumulation of p62- and ubiquitin-positive material in A-ICs of knockin mice suggested a defect in the degradative pathway, which may explain the observed loss of A-ICs. R607H knockin did not affect type B intercalated cells. We propose that reduced basolateral anion-exchange activity in A-ICs inhibits trafficking and regulation of V-type ATPase, compromising luminal H+ secretion and possibly lysosomal acidification.
Collapse
Affiliation(s)
- Rizwan Mumtaz
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Francesco Trepiccione
- Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Paris Descartes University, Department of Physiology, Hôpital Européen Georges Pompidou, Paris, France.,Department of Cardio-Thoracic and Respiratory Science, Second University of Naples, Naples, Italy
| | - J Christopher Hennings
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Antje K Huebner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Bettina Serbin
- Institut National de la Santé et de la Recherche Médicale U970, Paris Cardiovascular Research Center, Paris Descartes University, Department of Physiology, Hôpital Européen Georges Pompidou, Paris, France
| | - Nicolas Picard
- Centre National de la Recherche Scientifique, Équipe de Recherche Labellisée 8228, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche en Santé 1138, Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris, France
| | - A K M Shahid Ullah
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Teodor G Păunescu
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and
| | - Diane E Capen
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and
| | - Rawad M Lashhab
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Isabelle Mouro-Chanteloup
- Institut National de la Transfusion Sanguine, Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche en Santé 1134, Laboratory of Excellence Globule Rouge-Excellence, Paris Diderot University, Paris, France
| | - Seth L Alper
- Nephrology Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and
| | - Emmanuelle Cordat
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Dennis Brown
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and
| | - Dominique Eladari
- Service de Physiologie Explorations Fonctionnelles Rénales, Centre Hospitalier Universitaire de la Réunion, Hôpital Felix Guyon; and .,Institut National de la Santé et de la Recherche Médicale U1188 Diabète athérothrombose Thérapies Réunion Océan Indien (DéTROI), Saint Denis, La Réunion, France
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany;
| |
Collapse
|
31
|
Allosteric regulation by cooperative conformational changes of actin filaments drives mutually exclusive binding with cofilin and myosin. Sci Rep 2016; 6:35449. [PMID: 27762277 PMCID: PMC5071871 DOI: 10.1038/srep35449] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/29/2016] [Indexed: 01/25/2023] Open
Abstract
Heavy meromyosin (HMM) of myosin II and cofilin each binds to actin filaments cooperatively and forms clusters along the filaments, but it is unknown whether the two cooperative bindings are correlated and what physiological roles they have. Fluorescence microscopy demonstrated that HMM-GFP and cofilin-mCherry each bound cooperatively to different parts of actin filaments when they were added simultaneously in 0.2 μM ATP, indicating that the two cooperative bindings are mutually exclusive. In 0.1 mM ATP, the motor domain of myosin (S1) strongly inhibited the formation of cofilin clusters along actin filaments. Under this condition, most actin protomers were unoccupied by S1 at any given moment, suggesting that transiently bound S1 alters the structure of actin filaments cooperatively and/or persistently to inhibit cofilin binding. Consistently, cosedimentation experiments using copolymers of actin and actin-S1 fusion protein demonstrated that the fusion protein affects the neighboring actin protomers, reducing their affinity for cofilin. In reciprocal experiments, cofilin-actin fusion protein reduced the affinity of neighboring actin protomers for S1. Thus, allosteric regulation by cooperative conformational changes of actin filaments contributes to mutually exclusive cooperative binding of myosin II and cofilin to actin filaments, and presumably to the differential localization of both proteins in cells.
Collapse
|
32
|
Kobeissy FH, Hansen K, Neumann M, Fu S, Jin K, Liu J. Deciphering the Role of Emx1 in Neurogenesis: A Neuroproteomics Approach. Front Mol Neurosci 2016; 9:98. [PMID: 27799894 PMCID: PMC5065984 DOI: 10.3389/fnmol.2016.00098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/26/2016] [Indexed: 12/18/2022] Open
Abstract
Emx1 has long been implicated in embryonic brain development. Previously we found that mice null of Emx1 gene had smaller dentate gyri and reduced neurogenesis, although the molecular mechanisms underlying this defect was not well understood. To decipher the role of Emx1 gene in neural regeneration and the timing of its involvement, we determine the frequency of neural stem cells (NSCs) in embryonic and adult forebrains of Emx1 wild type (WT) and knock out (KO) mice in the neurosphere assay. Emx1 gene deletion reduced the frequency and self-renewal capacity of NSCs of the embryonic brain but did not affect neuronal or glial differentiation. Emx1 KO NSCs also exhibited a reduced migratory capacity in response to serum or vascular endothelial growth factor (VEGF) in the Boyden chamber migration assay compared to their WT counterparts. A thorough comparison between NSC lysates from Emx1 WT and KO mice utilizing 2D-PAGE coupled with tandem mass spectrometry revealed 38 proteins differentially expressed between genotypes, including the F-actin depolymerization factor Cofilin. A global systems biology and cluster analysis identified several potential mechanisms and cellular pathways implicated in altered neurogenesis, all involving Cofilin1. Protein interaction network maps with functional enrichment analysis further indicated that the differentially expressed proteins participated in neural-specific functions including brain development, axonal guidance, synaptic transmission, neurogenesis, and hippocampal morphology, with VEGF as the upstream regulator intertwined with Cofilin1 and Emx1. Functional validation analysis indicated that apart from the overall reduced level of phosphorylated Cofilin1 (p-Cofilin1) in the Emx1 KO NSCs compared to WT NSCs as demonstrated in the western blot analysis, VEGF was able to induce more Cofilin1 phosphorylation and FLK expression only in the latter. Our results suggest that a defect in Cofilin1 phosphorylation induced by VEGF or other growth factors might contribute to the reduced neurogenesis in the Emx1 null mice during brain development.
Collapse
Affiliation(s)
- Firas H Kobeissy
- Department of Psychiatry, Center for Neuroproteomics and Biomarkers Research, University of Florida Gainesville, FL, USA
| | - Katharina Hansen
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
| | - Melanie Neumann
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
| | - Shuping Fu
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA; Key Laboratory of Acupuncture and Medicine Research of Minister of Education, Nanjing University of Chinese MedicineNanjing, China
| | - Kulin Jin
- Pharmacology & Neuroscience, University of North Texas Health Science Center Fort Worth, TX, USA
| | - Jialing Liu
- Department of Neurological Surgery, University of California, San FranciscoSan Francisco, CA, USA; San Francisco VA Medical CenterSan Francisco, CA, USA
| |
Collapse
|
33
|
Chin SM, Jansen S, Goode BL. TIRF microscopy analysis of human Cof1, Cof2, and ADF effects on actin filament severing and turnover. J Mol Biol 2016; 428:1604-16. [PMID: 26996939 DOI: 10.1016/j.jmb.2016.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 02/29/2016] [Accepted: 03/09/2016] [Indexed: 10/24/2022]
Abstract
Dynamic remodeling and turnover of cellular actin networks requires actin filament severing by actin-depolymerizing factor (ADF)/Cofilin proteins. Mammals express three different ADF/Cofilins (Cof1, Cof2, and ADF), and genetic studies suggest that in vivo they perform both overlapping and unique functions. To gain mechanistic insights into their different roles, we directly compared their G-actin and F-actin binding affinities, and quantified the actin filament severing activities of human Cof1, Cof2, and ADF using in vitro total internal reflection fluorescence microscopy. All three ADF/Cofilins had similar affinities for G-actin and F-actin. However, Cof2 and ADF severed filaments much more efficiently than Cof1 at both lower and higher concentrations and using either muscle or platelet actin. Furthermore, Cof2 and ADF were more effective than Cof1 in promoting "enhanced disassembly" when combined with actin disassembly co-factors Coronin-1B and actin-interacting protein 1 (AIP1), and these differences were observed on both preformed and actively growing filaments. To probe the mechanism underlying these differences, we used multi-wavelength total internal reflection fluorescence microscopy to directly observe Cy3-Cof1 and Cy3-Cof2 interacting with actin filaments in real time during severing. Cof1 and Cof2 each bound to filaments with similar kinetics, yet Cof2 induced severing much more rapidly than Cof1, decreasing the time interval between initial binding on a filament and severing at the same location. These differences in ADF/Cofilin activities and mechanisms may be used in cells to tune filament turnover rates, which can vary widely for different actin structures.
Collapse
Affiliation(s)
- Samantha M Chin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA.
| |
Collapse
|
34
|
Nomura K, Hayakawa K, Tatsumi H, Ono S. Actin-interacting Protein 1 Promotes Disassembly of Actin-depolymerizing Factor/Cofilin-bound Actin Filaments in a pH-dependent Manner. J Biol Chem 2016; 291:5146-56. [PMID: 26747606 DOI: 10.1074/jbc.m115.713495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Indexed: 02/02/2023] Open
Abstract
Actin-interacting protein 1 (AIP1) is a conserved WD repeat protein that promotes disassembly of actin filaments when actin-depolymerizing factor (ADF)/cofilin is present. Although AIP1 is known to be essential for a number of cellular events involving dynamic rearrangement of the actin cytoskeleton, the regulatory mechanism of the function of AIP1 is unknown. In this study, we report that two AIP1 isoforms from the nematode Caenorhabditis elegans, known as UNC-78 and AIPL-1, are pH-sensitive in enhancement of actin filament disassembly. Both AIP1 isoforms only weakly enhance disassembly of ADF/cofilin-bound actin filaments at an acidic pH but show stronger disassembly activity at neutral and basic pH values. However, a severing-defective mutant of UNC-78 shows pH-insensitive binding to ADF/cofilin-decorated actin filaments, suggesting that the process of filament severing or disassembly, but not filament binding, is pH-dependent. His-60 of AIP1 is located near the predicted binding surface for the ADF/cofilin-actin complex, and an H60K mutation of AIP1 partially impairs its pH sensitivity, suggesting that His-60 is involved in the pH sensor for AIP1. These biochemical results suggest that pH-dependent changes in AIP1 activity might be a novel regulatory mechanism of actin filament dynamics.
Collapse
Affiliation(s)
- Kazumi Nomura
- From the Departments of Pathology and Cell Biology, Emory University, Atlanta, Georgia 30322
| | | | - Hitoshi Tatsumi
- Department of Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan, and the Department of Applied Biosciences, Kanazawa Institute of Technology, Kanazawa 924-0838, Japan
| | - Shoichiro Ono
- From the Departments of Pathology and Cell Biology, Emory University, Atlanta, Georgia 30322,
| |
Collapse
|
35
|
Mi N, Chen Y, Wang S, Chen M, Zhao M, Yang G, Ma M, Su Q, Luo S, Shi J, Xu J, Guo Q, Gao N, Sun Y, Chen Z, Yu L. CapZ regulates autophagosomal membrane shaping by promoting actin assembly inside the isolation membrane. Nat Cell Biol 2015; 17:1112-23. [DOI: 10.1038/ncb3215] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 07/01/2015] [Indexed: 12/16/2022]
|
36
|
Chen L, Shi K, Frary CE, Ditzel N, Hu H, Qiu W, Kassem M. Inhibiting actin depolymerization enhances osteoblast differentiation and bone formation in human stromal stem cells. Stem Cell Res 2015. [PMID: 26209815 DOI: 10.1016/j.scr.2015.06.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Remodeling of the actin cytoskeleton through actin dynamics is involved in a number of biological processes, but its role in human stromal (skeletal) stem cells (hMSCs) differentiation is poorly understood. In the present study, we demonstrated that stabilizing actin filaments by inhibiting gene expression of the two main actin depolymerizing factors (ADFs): Cofilin 1 (CFL1) and Destrin (DSTN) in hMSCs, enhanced cell viability and differentiation into osteoblastic cells (OB) in vitro, as well as heterotopic bone formation in vivo. Similarly, treating hMSC with Phalloidin, which is known to stabilize polymerized actin filaments, increased hMSCs viability and OB differentiation. Conversely, Cytocholasin D, an inhibitor of actin polymerization, reduced cell viability and inhibited OB differentiation of hMSC. At a molecular level, preventing Cofilin phosphorylation through inhibition of LIM domain kinase 1 (LIMK1) decreased cell viability and impaired OB differentiation of hMSCs. Moreover, depolymerizing actin reduced FAK, p38 and JNK activation during OB differentiation of hMSCs, while polymerizing actin enhanced these signaling pathways. Our results demonstrate that the actin dynamic reassembly and Cofilin phosphorylation loop is involved in the control of hMSC proliferation and osteoblasts differentiation.
Collapse
Affiliation(s)
- Li Chen
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark.
| | - Kaikai Shi
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark
| | - Charles Edward Frary
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark
| | - Nicholas Ditzel
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark
| | - Huimin Hu
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark; Department of Spine Surgery, Honghui Hospital, Xi'an JiaoTong University College of Medicine, 710054 Xi'an, China
| | - Weimin Qiu
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark
| | - Moustapha Kassem
- Molecular Endocrinology Laboratory (KMEB), Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark; Danish Stem Cell Center (DanStem), Panum Institute, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
37
|
Okochi Y, Aratani Y, Adissu HA, Miyawaki N, Sasaki M, Suzuki K, Okamura Y. The voltage-gated proton channel Hv1/VSOP inhibits neutrophil granule release. J Leukoc Biol 2015; 99:7-19. [PMID: 25990245 DOI: 10.1189/jlb.3hi0814-393r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/19/2015] [Indexed: 01/09/2023] Open
Abstract
Neutrophil granule exocytosis is crucial for host defense and inflammation. Neutrophils contain 4 types of granules, the exocytotic release of which is differentially regulated. This exocytosis is known to be driven by diverse mediators, including calcium and nucleotides, but the precise molecular mechanism remains largely unknown. We show in the present study that voltage-gated proton (Hv) channels are necessary for the proper release of azurophilic granules in neutrophils. On activation of NADPH oxidase by PMA and IgG, neutrophils derived from Hvcn1 gene knockout mouse exhibited greater secretion of MPO and elastase than WT cells. In contrast, release of LTF enriched in specific granules was not enhanced in these cells. The excess release of azurophilic granules in Hv1/VSOP-deficient neutrophils was suppressed by inhibiting NADPH oxidase activity and, in part, by valinomycin, a potassium ionophore. In addition, Hv1/VSOP-deficient mice exhibited more severe lung inflammation after intranasal Candida albicans infection than WT mice. These findings suggest that the Hv channel acts to specifically dampen the release of azurophilic granules through, in part, the suppression of increased positive charges at the plasma membrane accompanied by the activation of NADPH oxidase in neutrophils.
Collapse
Affiliation(s)
- Yoshifumi Okochi
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yasuaki Aratani
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Hibret A Adissu
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Nana Miyawaki
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Mari Sasaki
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Kazuo Suzuki
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yasushi Okamura
- *Integrative Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan; Department of Life and Environmental System Science, Graduate School of Nanobioscience, Yokohama City University, Kanagawa, Japan; Physiology & Experimental Medicine, Hospital for Sick Children, Ontario, Canada; Department of Bioactive Molecules and Bacteriology, National Institute of Infectious Diseases, Tokyo, Japan; and Inflammation Program, Department of Immunology, Graduate School of Medicine, Chiba University, Chiba, Japan; and Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| |
Collapse
|
38
|
Solution structures and dynamics of ADF/cofilins UNC-60A and UNC-60B from Caenorhabditis elegans. Biochem J 2015; 465:63-78. [PMID: 25279657 DOI: 10.1042/bj20140923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The nematode Caenorhabditis elegans has two ADF (actin-depolymerizing factor)/cofilin isoforms, UNC-60A and UNC-60B, which are expressed by the unc60 gene by alternative splicing. UNC-60A has higher activity to cause net depolymerization, and to inhibit polymerization, than UNC-60B. UNC-60B, on the other hand, shows much stronger severing activity than UNC-60A. To understand the structural basis of their functional differences, we have determined the solution structures of UNC-60A and UNC-60B proteins and characterized their backbone dynamics. Both UNC-60A and UNC-60B show a conserved ADF/cofilin fold. The G-actin (globular actin)-binding regions of the two proteins are structurally and dynamically conserved. Accordingly, UNC-60A and UNC-60B individually bind to rabbit muscle ADP-G-actin with high affinities, with Kd values of 32.25 nM and 8.62 nM respectively. The primary differences between these strong and weak severing proteins were observed in the orientation and dynamics of the F-actin (filamentous actin)-binding loop (F-loop). In the strong severing activity isoform UNC-60B, the orientation of the F-loop was towards the recently identified F-loop-binding region on F-actin, and the F-loop was relatively more flexible with 14 residues showing motions on a nanosecond-picosecond timescale. In contrast, in the weak severing protein isoform UNC-60A, the orientation of the F-loop was away from the F-loop-binding region and inclined towards its own C-terminal and strand β6. It was also relatively less flexible with only five residues showing motions on a nanosecond-picosecond timescale. These differences in structure and dynamics seem to directly correlate with the differential F-actin site-binding and severing properties of UNC-60A and UNC-60B, and other related ADF/cofilin proteins.
Collapse
|
39
|
Chemokine-Dependent pH Elevation at the Cell Front Sustains Polarity in Directionally Migrating Zebrafish Germ Cells. Curr Biol 2015; 25:1096-103. [PMID: 25843033 DOI: 10.1016/j.cub.2015.02.071] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 01/06/2015] [Accepted: 02/25/2015] [Indexed: 11/21/2022]
Abstract
Directional cell migration requires cell polarization with respect to the distribution of the guidance cue. Cell polarization often includes asymmetric distribution of response components as well as elements of the motility machinery. Importantly, the function and regulation of most of these molecules are known to be pH dependent. Intracellular pH gradients were shown to occur in certain cells migrating in vitro, but the functional relevance of such gradients for cell migration and for the response to directional cues, particularly in the intact organism, is currently unknown. In this study, we find that primordial germ cells migrating in the context of the developing embryo respond to the graded distribution of the chemokine Cxcl12 by establishing elevated intracellular pH at the cell front. We provide insight into the mechanisms by which a polar pH distribution contributes to efficient cell migration. Specifically, we show that Carbonic Anhydrase 15b, an enzyme controlling the pH in many cell types, including metastatic cancer cells, is expressed in migrating germ cells and is crucial for establishing and maintaining an asymmetric pH distribution within them. Reducing the level of the protein and thereby erasing the pH elevation at the cell front resulted in abnormal cell migration and impaired arrival at the target. The basis for the disrupted migration is found in the stringent requirement for pH conditions in the cell for regulating contractility, for the polarization of Rac1 activity, and hence for the formation of actin-rich structures at the leading edge of the migrating cells.
Collapse
|
40
|
Wilkins KA, Bosch M, Haque T, Teng N, Poulter NS, Franklin-Tong VE. Self-incompatibility-induced programmed cell death in field poppy pollen involves dramatic acidification of the incompatible pollen tube cytosol. PLANT PHYSIOLOGY 2015; 167:766-79. [PMID: 25630437 PMCID: PMC4347735 DOI: 10.1104/pp.114.252742] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/27/2015] [Indexed: 05/20/2023]
Abstract
Self-incompatibility (SI) is an important genetically controlled mechanism to prevent inbreeding in higher plants. SI involves highly specific interactions during pollination, resulting in the rejection of incompatible (self) pollen. Programmed cell death (PCD) is an important mechanism for destroying cells in a precisely regulated manner. SI in field poppy (Papaver rhoeas) triggers PCD in incompatible pollen. During SI-induced PCD, we previously observed a major acidification of the pollen cytosol. Here, we present measurements of temporal alterations in cytosolic pH ([pH]cyt); they were surprisingly rapid, reaching pH 6.4 within 10 min of SI induction and stabilizing by 60 min at pH 5.5. By manipulating the [pH]cyt of the pollen tubes in vivo, we show that [pH]cyt acidification is an integral and essential event for SI-induced PCD. Here, we provide evidence showing the physiological relevance of the cytosolic acidification and identify key targets of this major physiological alteration. A small drop in [pH]cyt inhibits the activity of a soluble inorganic pyrophosphatase required for pollen tube growth. We also show that [pH]cyt acidification is necessary and sufficient for triggering several key hallmark features of the SI PCD signaling pathway, notably activation of a DEVDase/caspase-3-like activity and formation of SI-induced punctate actin foci. Importantly, the actin binding proteins Cyclase-Associated Protein and Actin-Depolymerizing Factor are identified as key downstream targets. Thus, we have shown the biological relevance of an extreme but physiologically relevant alteration in [pH]cyt and its effect on several components in the context of SI-induced events and PCD.
Collapse
Affiliation(s)
- Katie A Wilkins
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Maurice Bosch
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Tamanna Haque
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Nianjun Teng
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Natalie S Poulter
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | | |
Collapse
|
41
|
Ngo KX, Kodera N, Katayama E, Ando T, Uyeda TQP. Cofilin-induced unidirectional cooperative conformational changes in actin filaments revealed by high-speed atomic force microscopy. eLife 2015; 4. [PMID: 25642645 PMCID: PMC4337605 DOI: 10.7554/elife.04806] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/02/2015] [Indexed: 01/12/2023] Open
Abstract
High-speed atomic force microscopy was employed to observe structural changes in actin filaments induced by cofilin binding. Consistent with previous electron and fluorescence microscopic studies, cofilin formed clusters along actin filaments, where the filaments were 2-nm thicker and the helical pitch was ∼25% shorter, compared to control filaments. Interestingly, the shortened helical pitch was propagated to the neighboring bare zone on the pointed-end side of the cluster, while the pitch on the barbed-end side was similar to the control. Thus, cofilin clusters induce distinctively asymmetric conformational changes in filaments. Consistent with the idea that cofilin favors actin structures with a shorter helical pitch, cofilin clusters grew unidirectionally toward the pointed-end of the filament. Severing was often observed near the boundaries between bare zones and clusters, but not necessarily at the boundaries. DOI:http://dx.doi.org/10.7554/eLife.04806.001 Actin is one of the most abundant proteins found inside all eukaryotic cells including plant, animal, and fungal cells. This protein is involved in a wide range of biological processes that are essential for an organism's survival. Actin proteins form long filaments that help cells to maintain their shape and also provide the force required for cells to divide and/or move. Actin filaments are helical in shape and are made up of many actin subunits joined together. Actin filaments are changeable structures that continuously grow and shrink as new actin subunits are added to or removed from the ends of the filaments. One end of an actin filament grows faster than the other; the fast-growing end is known as the barbed-end, while the slow-growing end is referred to as the pointed-end. Over 100 other proteins are known to bind to and work with actin to regulate its roles in cells and how it forms into filaments. Cofilin is one such protein that binds to and forms clusters on actin filaments and it can also sever actin filaments. Severing an actin filament can encourage the filament to disassemble, or it can help produce new barbed ends that can then grow into new filaments. Previous work had suggested that cofilin severs actin filaments at the junction between regions on the filament that are coated with cofilin and those that are not. It was also known that cofilin binding to a filament causes the filament to change shape, and that the shape change is propagated to neighboring sections of the filaments not coated with cofilin. However, the details of where cofilin binds and how changes in shape are propagated along an actin filament were not known. Furthermore, the findings of these previous studies were largely based on examining still images of actin filaments, which are unlike the constantly changing filaments of living cells. Ngo, Kodera et al. have now analyzed what happens when cofilin binds to and forms clusters along actin filaments using a recently developed imaging technique called high-speed atomic force microscopy. This technique can be used to directly visualize individual proteins in action. Consistent with previous findings, Ngo, Kodera et al. observed that filaments coated with cofilin are thicker than those filaments without cofilin; and that cofilin binding also substantially reduces the helical twist of the filament. Ngo, Kodera et al. also found that these changes in shape are propagated along the filament but in only one direction—towards the pointed-end. Moreover, cofilin clusters also only grew towards the pointed-end of the actin filament—and the filaments were often severed near, but not exactly at, the junctions between cofilin-coated and uncoated regions. Such one-directional changes in shape of the actin filaments presumably help to regulate how other actin binding proteins can interact with the filament and consequently regulate the roles of the filaments themselves. DOI:http://dx.doi.org/10.7554/eLife.04806.002
Collapse
Affiliation(s)
- Kien Xuan Ngo
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Noriyuki Kodera
- Department of Physics and Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, Japan
| | - Eisaku Katayama
- Department of Biology, Graduate School of Science, Osaka City University, Osaka, Japan
| | - Toshio Ando
- Department of Physics and Bio-AFM Frontier Research Center, Kanazawa University, Kanazawa, Japan
| | - Taro Q P Uyeda
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| |
Collapse
|
42
|
Kremneva E, Makkonen MH, Skwarek-Maruszewska A, Gateva G, Michelot A, Dominguez R, Lappalainen P. Cofilin-2 controls actin filament length in muscle sarcomeres. Dev Cell 2015; 31:215-26. [PMID: 25373779 DOI: 10.1016/j.devcel.2014.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/03/2014] [Accepted: 09/03/2014] [Indexed: 01/26/2023]
Abstract
ADF/cofilins drive cytoskeletal dynamics by promoting the disassembly of "aged" ADP-actin filaments. Mammals express several ADF/cofilin isoforms, but their specific biochemical activities and cellular functions have not been studied in detail. Here, we demonstrate that the muscle-specific isoform cofilin-2 promotes actin filament disassembly in sarcomeres to control the precise length of thin filaments in the contractile apparatus. In contrast to other isoforms, cofilin-2 efficiently binds and disassembles both ADP- and ATP/ADP-Pi-actin filaments. We mapped surface-exposed cofilin-2-specific residues required for ATP-actin binding and propose that these residues function as an "actin nucleotide-state sensor" among ADF/cofilins. The results suggest that cofilin-2 evolved specific biochemical and cellular properties that allow it to control actin dynamics in sarcomeres, where filament pointed ends may contain a mixture of ADP- and ATP/ADP-Pi-actin subunits. Our findings also offer a rationale for why cofilin-2 mutations in humans lead to myopathies.
Collapse
Affiliation(s)
- Elena Kremneva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Maarit H Makkonen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | | | - Gergana Gateva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Alphee Michelot
- Laboratoire de Physiologie Cellulaire et Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, iRTSV, CNRS/CEA/INRA/UJF, 38054 Grenoble, France
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
| |
Collapse
|
43
|
Human defensins facilitate local unfolding of thermodynamically unstable regions of bacterial protein toxins. Immunity 2014; 41:709-21. [PMID: 25517613 DOI: 10.1016/j.immuni.2014.10.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 09/17/2014] [Indexed: 02/08/2023]
Abstract
Defensins are short cationic, amphiphilic, cysteine-rich peptides that constitute the front-line immune defense against various pathogens. In addition to exerting direct antibacterial activities, defensins inactivate several classes of unrelated bacterial exotoxins. To date, no coherent mechanism has been proposed to explain defensins' enigmatic efficiency toward various toxins. In this study, we showed that binding of neutrophil ?-defensin HNP1 to affected bacterial toxins caused their local unfolding, potentiated their thermal melting and precipitation, exposed new regions for proteolysis, and increased susceptibility to collisional quenchers without causing similar effects on tested mammalian structural and enzymatic proteins. Enteric ?-defensin HD5 and ?-defensin hBD2 shared similar toxin-unfolding effects with HNP1, albeit to different degrees. We propose that protein susceptibility to inactivation by defensins is contingent to their thermolability and conformational plasticity and that defensin-induced unfolding is a key element in the general mechanism of toxin inactivation by human defensins.
Collapse
|
44
|
Single-molecule imaging and kinetic analysis of cooperative cofilin-actin filament interactions. Proc Natl Acad Sci U S A 2014; 111:9810-5. [PMID: 24958883 DOI: 10.1073/pnas.1321451111] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The actin filament-severing protein actin depolymerizing factor (ADF)/cofilin is ubiquitously distributed among eukaryotes and modulates actin dynamics. The cooperative binding of cofilin to actin filaments is crucial for the concentration-dependent unconventional modulation of actin dynamics by cofilin. In this study, the kinetic parameters associated with the cooperative binding of cofilin to actin filaments were directly evaluated using a single-molecule imaging technique. The on-rate of cofilin binding to the actin filament was estimated to be 0.06 µM(-1)⋅s(-1) when the cofilin concentration was in the range of 30 nM to 1 µM. A dwell time histogram of cofilin bindings decays exponentially to give an off-rate of 0.6 s(-1). During long-term cofilin binding events (>0.4 s), additional cofilin bindings were observed in the vicinity of the initial binding site. The on-rate for these events was 2.3-fold higher than that for noncontiguous bindings. Super-high-resolution image analysis of the cofilin binding location showed that the on-rate enhancement occurred within 65 nm of the original binding event. By contrast, the cofilin off-rate was not affected by the presence of prebound cofilin. Neither decreasing the temperature nor increasing the viscosity of the test solution altered the on-rates, off-rates, or the cooperative parameter (ω) of the binding. These results indicate that cofilin binding enhances additional cofilin binding in the vicinity of the initial binding site (ca. 24 subunits), but it does not affect the off-rate, which could be the molecular mechanism of the cooperative binding of cofilin to actin filaments.
Collapse
|
45
|
Aggeli D, Kish-Trier E, Lin MC, Haarer B, Cingolani G, Cooper JA, Wilkens S, Amberg DC. Coordination of the filament stabilizing versus destabilizing activities of cofilin through its secondary binding site on actin. Cytoskeleton (Hoboken) 2014; 71:361-79. [PMID: 24943913 PMCID: PMC4241054 DOI: 10.1002/cm.21178] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/29/2014] [Indexed: 11/08/2022]
Abstract
Cofilin is a ubiquitous modulator of actin cytoskeleton dynamics that can both stabilize and destabilize actin filaments depending on its concentration and/or the presence of regulatory co-factors. Three charge-reversal mutants of yeast cofilin, located in cofilin's filament-specific secondary binding site, were characterized in order to understand why disruption of this site leads to enhanced filament disassembly. Crystal structures of the mutants showed that the mutations specifically affect the secondary actin-binding interface, leaving the primary binding site unaltered. The mutant cofilins show enhanced activity compared to wild-type cofilin in severing and disassembling actin filaments. Electron microscopy and image analysis revealed long actin filaments in the presence of wild-type cofilin, while the mutants induced many short filaments, consistent with enhanced severing. Real-time fluorescence microscopy of labeled actin filaments confirmed that the mutants, unlike wild-type cofilin, were functioning as constitutively active severing proteins. In cells, the mutant cofilins delayed endocytosis, which depends on rapid actin turnover. We conclude that mutating cofilin's secondary actin-binding site increases cofilin's ability to sever and de-polymerize actin filaments. We hypothesize that activators of cofilin severing, like Aip1p, may act by disrupting the interface between cofilin's secondary actin-binding site and the actin filament.
Collapse
Affiliation(s)
- Dimitra Aggeli
- SUNY Upstate Medical University, Department of Biochemistry and Molecular Biology, 750 E. Adams Street, Syracuse, NY 13159
| | - Erik Kish-Trier
- University of Utah, Department of Biochemistry, 15 N Medical Drive East, Salt Lake City, UT 84112-5650
| | - Meng Chi Lin
- Early Embryogenesis Lab, Center for Developmental Biology, Riken, Japan
| | - Brian Haarer
- SUNY Upstate Medical University, Department of Biochemistry and Molecular Biology, 750 E. Adams Street, Syracuse, NY 13159
| | - Gino Cingolani
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, 233 South 10th Street, Philadelphia, PA 19107
| | - John A. Cooper
- Washington University in St. Louis, Department of Cell Biology and Physiology, 660 South Euclid Avenue, St. Louis, MO 63110
| | - Stephan Wilkens
- SUNY Upstate Medical University, Department of Biochemistry and Molecular Biology, 750 E. Adams Street, Syracuse, NY 13159
| | - David C. Amberg
- SUNY Upstate Medical University, Department of Biochemistry and Molecular Biology, 750 E. Adams Street, Syracuse, NY 13159
| |
Collapse
|
46
|
Ono S. The role of cyclase-associated protein in regulating actin filament dynamics - more than a monomer-sequestration factor. J Cell Sci 2014; 126:3249-58. [PMID: 23908377 DOI: 10.1242/jcs.128231] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is fundamental to a number of cell biological events. A variety of actin-regulatory proteins modulate polymerization and depolymerization of actin and contribute to actin cytoskeletal reorganization. Cyclase-associated protein (CAP) is a conserved actin-monomer-binding protein that has been studied for over 20 years. Early studies have shown that CAP sequesters actin monomers; recent studies, however, have revealed more active roles of CAP in actin filament dynamics. CAP enhances the recharging of actin monomers with ATP antagonistically to ADF/cofilin, and also promotes the severing of actin filaments in cooperation with ADF/cofilin. Self-oligomerization and binding to other proteins regulate activities and localization of CAP. CAP has crucial roles in cell signaling, development, vesicle trafficking, cell migration and muscle sarcomere assembly. This Commentary discusses the recent advances in our understanding of the functions of CAP and its implications as an important regulator of actin cytoskeletal dynamics, which are involved in various cellular activities.
Collapse
Affiliation(s)
- Shoichiro Ono
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
| |
Collapse
|
47
|
Jiao Y, Walker M, Trinick J, Pernier J, Montaville P, Carlier MF. Mutagenetic and electron microscopy analysis of actin filament severing by Cordon-Bleu, a WH2 domain protein. Cytoskeleton (Hoboken) 2014; 71:170-83. [PMID: 24415668 DOI: 10.1002/cm.21161] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/11/2013] [Accepted: 12/30/2013] [Indexed: 12/29/2022]
Abstract
Cordon-Bleu (Cobl) is a regulator of actin dynamics in neural development and ciliogenesis. Its function is associated with three adjacent actin binding WASP Homology 2 (WH2) domains. We showed that these WH2 repeats confer multifunctional regulation of actin dynamics, which makes Cobl a « dynamizer » of actin assembly, inducing fast turnover of actin filaments and oscillatory polymerization regime via nucleation, severing, and rapid depolymerization activities. Cobl is the most efficient severer of actin filaments characterized so far. To understand which primary sequence elements determine the filament severing activity of the WH2 repeats, here we combine a mutagenetic/domain swapping approach of the minimal fully active Cobl-KAB construct, which comprises the lysine rich region K preceding the two first WH2 domains A and B. The mutated Cobl constructs display variable loss of the original filament nucleating activities of native Cobl-KAB, without any strict correlation with a loss in actin binding, which emphasizes the functional importance of the electrostatic environment of WH2 domains. Filament severing displayed the greatest stringency and was abolished in all mutated forms of Cobl-KAB. Filament severing and re-annealing by Cobl-KAB, which is key in its rapid remodeling of a population of actin filaments, and most likely responsible for its function in ciliogenesis, was analyzed by electron microscopy in comparison with Spire and ADF.
Collapse
Affiliation(s)
- Yue Jiao
- Cytoskeleton Dynamics and Cell Motility Team, Laboratoire d'Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, 91198, Gif-sur-Yvette, France
| | | | | | | | | | | |
Collapse
|
48
|
Tahtamouni LH, Shaw AE, Hasan MH, Yasin SR, Bamburg JR. Non-overlapping activities of ADF and cofilin-1 during the migration of metastatic breast tumor cells. BMC Cell Biol 2013; 14:45. [PMID: 24093776 PMCID: PMC3850953 DOI: 10.1186/1471-2121-14-45] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/01/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND ADF/cofilin proteins are key modulators of actin dynamics in metastasis and invasion of cancer cells. Here we focused on the roles of ADF and cofilin-1 individually in the development of polarized migration of rat mammary adenocarcinoma (MTLn3) cells, which express nearly equal amounts of each protein. Small interference RNA (siRNA) technology was used to knockdown (KD) the expression of ADF and cofilin-1 independently. RESULTS Either ADF KD or cofilin KD caused cell elongation, a reduction in cell area, a decreased ability to form invadopodia, and a decreased percentage of polarized cells after 180 s of epidermal growth factor stimulation. Moreover, ADF KD or cofilin KD increased the rate of cell migration and the time of lamellipodia protrusion but through different mechanisms: lamellipodia protrude more frequently in ADF KD cells and are more persistent in cofilin KD cells. ADF KD cells showed a significant increase in F-actin aggregates, whereas cofilin KD cells showed a significant increase in prominent F-actin bundles and increased cell adhesion. Focal adhesion area and cell adhesion in cofilin KD cells were returned to control levels by expressing exogenous cofilin but not ADF. Return to control rates of cell migration in ADF KD cells was achieved by expression of exogenous ADF but not cofilin, whereas in cofilin KD cells, expression of cofilin efficiently rescued control migration rates. CONCLUSION Although ADF and cofilin have many redundant functions, each of these isoforms has functional differences that affect F-actin structures, cell adhesion and lamellipodial dynamics, all of which are important determinants of cell migration.
Collapse
Affiliation(s)
- Lubna H Tahtamouni
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13115, Jordan
| | - Alisa E Shaw
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Maram H Hasan
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13115, Jordan
| | - Salem R Yasin
- Department of Biology and Biotechnology, Faculty of Science, The Hashemite University, Zarqa 13115, Jordan
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| |
Collapse
|
49
|
Elam WA, Kang H, De La Cruz EM. Competitive displacement of cofilin can promote actin filament severing. Biochem Biophys Res Commun 2013; 438:728-31. [PMID: 23911787 DOI: 10.1016/j.bbrc.2013.07.109] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 07/27/2013] [Indexed: 11/30/2022]
Abstract
Cofilin is an essential actin filament severing protein that functions in the dynamic remodeling of the actin cytoskeleton. Filament severing activity is most efficient at sub-stoichiometric cofilin binding densities (i.e. <1 cofilin per actin filament subunit), and peaks when the number density of boundaries (i.e. junctions) between bare and cofilin-decorated segments is maximal. A model in which local topological and mechanical discontinuities lead to preferential fragmentation at boundaries accounts for available experimental data, including direct visualization of cofilin and actin during real-time severing events. The boundary-severing model predicts that ligands (e.g. other actin-binding proteins) that compete with cofilin for actin filament binding and modulate cofilin occupancy on filaments will alter the bare-decorated segment boundary density, and thus, the filament severing activity of cofilin. Here, we directly test this model prediction by evaluating the effects of phalloidin and myosin, two ligands that compete with cofilin for filament binding, on the actin filament binding and severing activities of cofilin. Our experiments demonstrate that competitive displacement of cofilin lowers cofilin occupancy and promotes severing when initial cofilin occupancy is high (i.e. >50%). Even in the presence of competitive ligands, maximum severing activity occurs when cofilin-decorated boundary density is highest, consistent with preferential fragmentation at boundaries. We propose a general "severodyne" framework for the modulation of cofilin-mediated actin filament severing by small molecule or actin-binding protein ligands that compete with cofilin for actin filament binding.
Collapse
Affiliation(s)
- W Austin Elam
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | | |
Collapse
|
50
|
Bravo-Cordero JJ, Magalhaes MAO, Eddy RJ, Hodgson L, Condeelis J. Functions of cofilin in cell locomotion and invasion. Nat Rev Mol Cell Biol 2013; 14:405-15. [PMID: 23778968 DOI: 10.1038/nrm3609] [Citation(s) in RCA: 362] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recently, a consensus has emerged that cofilin severing activity can generate free actin filament ends that are accessible for F-actin polymerization and depolymerization without changing the rate of G-actin association and dissociation at either filament end. The structural basis of actin filament severing by cofilin is now better understood. These results have been integrated with recently discovered mechanisms for cofilin activation in migrating cells, which led to new models for cofilin function that provide insights into how cofilin regulation determines the temporal and spatial control of cell behaviour.
Collapse
Affiliation(s)
- Jose Javier Bravo-Cordero
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Avenue, Bronx, New York 10461, USA.
| | | | | | | | | |
Collapse
|