1
|
Structure and function of an atypical homodimeric actin capping protein from the malaria parasite. Cell Mol Life Sci 2022; 79:125. [PMID: 35132495 PMCID: PMC8821504 DOI: 10.1007/s00018-021-04032-0] [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: 09/09/2021] [Revised: 10/28/2021] [Accepted: 11/09/2021] [Indexed: 11/27/2022]
Abstract
Apicomplexan parasites, such as Plasmodium spp., rely on an unusual actomyosin motor, termed glideosome, for motility and host cell invasion. The actin filaments are maintained by a small set of essential regulators, which provide control over actin dynamics in the different stages of the parasite life cycle. Actin filament capping proteins (CPs) are indispensable heterodimeric regulators of actin dynamics. CPs have been extensively characterized in higher eukaryotes, but their role and functional mechanism in Apicomplexa remain enigmatic. Here, we present the first crystal structure of a homodimeric CP from the malaria parasite and compare the homo- and heterodimeric CP structures in detail. Despite retaining several characteristics of a canonical CP, the homodimeric Plasmodium berghei (Pb)CP exhibits crucial differences to the canonical heterodimers. Both homo- and heterodimeric PbCPs regulate actin dynamics in an atypical manner, facilitating rapid turnover of parasite actin, without affecting its critical concentration. Homo- and heterodimeric PbCPs show partially redundant activities, possibly to rescue actin filament capping in life cycle stages where the β-subunit is downregulated. Our data suggest that the homodimeric PbCP also influences actin kinetics by recruiting lateral actin dimers. This unusual function could arise from the absence of a β-subunit, as the asymmetric PbCP homodimer lacks structural elements essential for canonical barbed end interactions suggesting a novel CP binding mode. These findings will facilitate further studies aimed at elucidating the precise actin filament capping mechanism in Plasmodium.
Collapse
|
2
|
Bendes ÁÁ, Chatterjee M, Götte B, Kursula P, Kursula I. Functional homo- and heterodimeric actin capping proteins from the malaria parasite. Biochem Biophys Res Commun 2020; 525:681-686. [PMID: 32139121 DOI: 10.1016/j.bbrc.2020.02.119] [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: 02/14/2020] [Accepted: 02/20/2020] [Indexed: 12/23/2022]
Abstract
Actin capping proteins belong to the core set of proteins minimally required for actin-based motility and are present in virtually all eukaryotic cells. They bind to the fast-growing barbed end of an actin filament, preventing addition and loss of monomers, thus restricting growth to the slow-growing pointed end. Actin capping proteins are usually heterodimers of two subunits. The Plasmodium orthologs are an exception, as their α subunits are able to form homodimers. We show here that, while the β subunit alone is unstable, the α subunit of the Plasmodium actin capping protein forms functional homo- and heterodimers. This implies independent functions for the αα homo- and αβ heterodimers in certain stages of the parasite life cycle. Structurally, the homodimers resemble canonical αβ heterodimers, although certain rearrangements at the interface must be required. Both homo- and heterodimers bind to actin filaments in a roughly equimolar ratio, indicating they may also bind other sites than barbed ends.
Collapse
Affiliation(s)
- Ábris Ádám Bendes
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, 90014, Oulu, Finland.
| | - Moon Chatterjee
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and DESY, Notkestrasse 85, 22607, Hamburg, Germany.
| | - Benjamin Götte
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and DESY, Notkestrasse 85, 22607, Hamburg, Germany.
| | - Petri Kursula
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, 90014, Oulu, Finland; Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen, 5009, Norway.
| | - Inari Kursula
- Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, P.O. Box 5400, 90014, Oulu, Finland; Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and DESY, Notkestrasse 85, 22607, Hamburg, Germany; Department of Biomedicine, University of Bergen, Jonas Lies vei 91, Bergen, 5009, Norway.
| |
Collapse
|
3
|
Avenarius MR, Krey JF, Dumont RA, Morgan CP, Benson CB, Vijayakumar S, Cunningham CL, Scheffer DI, Corey DP, Müller U, Jones SM, Barr-Gillespie PG. Heterodimeric capping protein is required for stereocilia length and width regulation. J Cell Biol 2017; 216:3861-3881. [PMID: 28899994 PMCID: PMC5674897 DOI: 10.1083/jcb.201704171] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023] Open
Abstract
Control of the dimensions of actin-rich processes like filopodia, lamellipodia, microvilli, and stereocilia requires the coordinated activity of many proteins. Each of these actin structures relies on heterodimeric capping protein (CAPZ), which blocks actin polymerization at barbed ends. Because dimension control of the inner ear's stereocilia is particularly precise, we studied the CAPZB subunit in hair cells. CAPZB, present at ∼100 copies per stereocilium, concentrated at stereocilia tips as hair cell development progressed, similar to the CAPZB-interacting protein TWF2. We deleted Capzb specifically in hair cells using Atoh1-Cre, which eliminated auditory and vestibular function. Capzb-null stereocilia initially developed normally but later shortened and disappeared; surprisingly, stereocilia width decreased concomitantly with length. CAPZB2 expressed by in utero electroporation prevented normal elongation of vestibular stereocilia and irregularly widened them. Together, these results suggest that capping protein participates in stereocilia widening by preventing newly elongating actin filaments from depolymerizing.
Collapse
Affiliation(s)
- Matthew R. Avenarius
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Jocelyn F. Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Rachel A. Dumont
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Clive P. Morgan
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Connor B. Benson
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Sarath Vijayakumar
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | | | | | - David P. Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA
| | - Ulrich Müller
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD
| | - Sherri M. Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR,Correspondence to Peter G. Barr-Gillespie:
| |
Collapse
|
4
|
Khaitlina S, Tsaplina O, Hinssen H. Cooperative effects of tropomyosin on the dynamics of the actin filament. FEBS Lett 2017; 591:1884-1891. [PMID: 28555876 DOI: 10.1002/1873-3468.12700] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/19/2017] [Accepted: 05/22/2017] [Indexed: 12/26/2022]
Abstract
Tropomyosin (Tpm) plays an important role in regulating the organisation and functions of the actin cytoskeleton. Here, we describe a new approach to analyse the effects of Tpm on actin dynamics. Using F-actin proteolytically modified within the DNase-binding loop (ECP-actin), we show that Tpm binding almost completely suppresses the increased subunit exchange intrinsic for this F-actin. The effect is both concentration-dependent and cooperative, with half-maximal inhibition observed at about a 1 : 50 Tpm : actin ratio. Tpm decreases not only the number concentration of ECP-actin filaments, but also the rate of the filament subunit exchange. Our data suggest that Tpm regulates the dynamics of actin filaments by an allosteric strengthening of intermonomer contacts in the actin filament, and that this mechanism may be involved in the modulation of cytoskeletal dynamics.
Collapse
Affiliation(s)
| | | | - Horst Hinssen
- Faculty of Biology, University of Bielefeld, Bielefeld, Germany
| |
Collapse
|
5
|
Ganter M, Rizopoulos Z, Schüler H, Matuschewski K. Pivotal and distinct role for Plasmodium actin capping protein alpha during blood infection of the malaria parasite. Mol Microbiol 2015; 96:84-94. [PMID: 25565321 PMCID: PMC4413046 DOI: 10.1111/mmi.12922] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2015] [Indexed: 11/28/2022]
Abstract
Accurate regulation of microfilament dynamics is central to cell growth, motility and response to environmental stimuli. Stabilizing and depolymerizing proteins control the steady-state levels of filamentous (F-) actin. Capping protein (CP) binds to free barbed ends, thereby arresting microfilament growth and restraining elongation to remaining free barbed ends. In all CPs characterized to date, alpha and beta subunits form the active heterodimer. Here, we show in a eukaryotic parasitic cell that the two CP subunits can be functionally separated. Unlike the beta subunit, the CP alpha subunit of the apicomplexan parasite Plasmodium is refractory to targeted gene deletion during blood infection in the mammalian host. Combinatorial complementation of Plasmodium berghei CP genes with the orthologs from Plasmodium falciparum verified distinct activities of CP alpha and CP alpha/beta during parasite life cycle progression. Recombinant Plasmodium CP alpha could be produced in Escherichia coli in the absence of the beta subunit and the protein displayed F-actin capping activity. Thus, the functional separation of two CP subunits in a parasitic eukaryotic cell and the F-actin capping activity of CP alpha expand the repertoire of microfilament regulatory mechanisms assigned to CPs.
Collapse
Affiliation(s)
- Markus Ganter
- Parasitology Unit, Max Planck Institute for Infection Biology, 10117, Berlin, Germany; Department of Immunology and Infectious Disease, Harvard School of Public Health, Boston, MA, 02115, USA
| | | | | | | |
Collapse
|
6
|
Subunits of the Drosophila actin-capping protein heterodimer regulate each other at multiple levels. PLoS One 2014; 9:e96326. [PMID: 24788460 PMCID: PMC4008575 DOI: 10.1371/journal.pone.0096326] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/07/2014] [Indexed: 01/23/2023] Open
Abstract
The actin-Capping Protein heterodimer, composed of the α and β subunits, is a master F-actin regulator. In addition to its role in many cellular processes, Capping Protein acts as a main tumor suppressor module in Drosophila and in humans, in part, by restricting the activity of Yorkie/YAP/TAZ oncogenes. We aimed in this report to understand how both subunits regulate each other in vivo. We show that the levels and capping activities of both subunits must be tightly regulated to control F-actin levels and consequently growth of the Drosophila wing. Overexpressing capping protein α and β decreases both F-actin levels and tissue growth, while expressing forms of Capping Protein that have dominant negative effects on F-actin promote tissue growth. Both subunits regulate each other's protein levels. In addition, overexpressing one of the subunit in tissues knocked-down for the other increases the mRNA and protein levels of the subunit knocked-down and compensates for its loss. We propose that the ability of the α and β subunits to control each other's levels assures that a pool of functional heterodimer is produced in sufficient quantities to restrict the development of tumor but not in excess to sustain normal tissue growth.
Collapse
|
7
|
Togashi H, Nara T, Sekikawa C, Kawakami M, Yaginuma N, Tsunoda T, Sakaguchi K, Mizukami F. Refolding of lactate dehydrogenase by zeolite beta. Biotechnol Prog 2009; 25:200-6. [DOI: 10.1002/btpr.107] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
8
|
Cooper JA, Sept D. New insights into mechanism and regulation of actin capping protein. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 267:183-206. [PMID: 18544499 DOI: 10.1016/s1937-6448(08)00604-7] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The heterodimeric actin capping protein, referred to here as "CP," is an essential element of the actin cytoskeleton, binding to the barbed ends of actin filaments and regulating their polymerization. In vitro, CP has a critical role in the dendritic nucleation process of actin assembly mediated by Arp2/3 complex, and in vivo, CP is important for actin assembly and actin-based process of morphogenesis and differentiation. Recent studies have provided new insight into the mechanism of CP binding the barbed end, which raises new possibilities for the dynamics of CP and actin in cells. In addition, a number of molecules that bind and regulate CP have been discovered, suggesting new ideas for how CP may integrate into diverse processes of cell physiology.
Collapse
Affiliation(s)
- John A Cooper
- Department of Cell Biology, Washington University, St. Louis, MO 63110, USA
| | | |
Collapse
|
9
|
Refolding and activation of recombinant N-carbamoyl-d-amino acid amidohydrolase from Escherichia coli inclusion bodies. Process Biochem 2005. [DOI: 10.1016/j.procbio.2004.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
10
|
Lefebvre BG, Gage MJ, Robinson AS. Maximizing recovery of native protein from aggregates by optimizing pressure treatment. Biotechnol Prog 2004; 20:623-9. [PMID: 15059011 DOI: 10.1021/bp034221v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recovering native protein from aggregates is a common obstacle in the production of recombinant proteins. Recent reports have shown that hydrostatic pressure is an attractive alternative to traditional denature-and-dilute techniques, both in terms of yield and process simplicity. To determine the effect of process variables, we subjected tailspike aggregates to a variety of pressure-treatment conditions. Maximum native tailspike yields were obtained with only short pressure incubations (<5 min) at 240 MPa. However, some tailspike aggregates were resistant to pressure, despite multiple cycles of pressure. Extending the postpressure incubation time to 4 days improved the yield of native protein from aggregates from 19.4 +/- 0.9 to 47.4 +/- 19.6 microg/mL (approximately 78% yield of native trimer from nonaggregate material). The nearly exclusive conversion of monomer to trimer over the time scale of days, when combined with previous kinetic data, allows for the identification of three postpressure kinetic phases: a rapid phase consisting of structured dimer conversion to trimer (30 min), an intermediate phase consisting of monomer conversion to aggregate (100 min), and a slow phase consisting of conversion of monomer to trimer (days). Optimizing the production of structured dimer can yield the highest level of folded protein. Typical refolding additives, such as glycerol, or low-temperature incubation did not improve yields.
Collapse
Affiliation(s)
- Brian G Lefebvre
- Department of Chemical Engineering, University of Delaware, Newark, Delaware 19716, USA
| | | | | |
Collapse
|
11
|
Shumilina EV, Negulyaev YA, Morachevskaya EA, Hinssen H, Khaitlina SY. Regulation of sodium channel activity by capping of actin filaments. Mol Biol Cell 2003; 14:1709-16. [PMID: 12686620 PMCID: PMC153133 DOI: 10.1091/mbc.e02-09-0622] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Ion transport in various tissues can be regulated by the cortical actin cytoskeleton. Specifically, involvement of actin dynamics in the regulation of nonvoltage-gated sodium channels has been shown. Herein, inside-out patch clamp experiments were performed to study the effect of the heterodimeric actin capping protein CapZ on sodium channel regulation in leukemia K562 cells. The channels were activated by cytochalasin-induced disruption of actin filaments and inactivated by G-actin under ionic conditions promoting rapid actin polymerization. CapZ had no direct effect on channel activity. However, being added together with G-actin, CapZ prevented actin-induced channel inactivation, and this effect occurred at CapZ/actin molar ratios from 1:5 to 1:100. When actin was allowed to polymerize at the plasma membrane to induce partial channel inactivation, subsequent addition of CapZ restored the channel activity. These results can be explained by CapZ-induced inhibition of further assembly of actin filaments at the plasma membrane due to the modification of actin dynamics by CapZ. No effect on the channel activity was observed in response to F-actin, confirming that the mechanism of channel inactivation does not involve interaction of the channel with preformed filaments. Our data show that actin-capping protein can participate in the cytoskeleton-associated regulation of sodium transport in nonexcitable cells.
Collapse
|