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Abstract
Secretory pore-forming proteins (PFPs) have been identified in organisms from all kingdoms of life. Our studies with the toad species Bombina maxima found an interaction network among aerolysin family PFPs (af-PFPs) and trefoil factors (TFFs). As a toad af-PFP, BmALP1 can be reversibly regulated between active and inactive forms, with its paralog BmALP3 acting as a negative regulator. BmALP1 interacts with BmTFF3 to form a cellular active complex called βγ-CAT. This PFP complex is characterized by acting on endocytic pathways and forming pores on endolysosomes, including stimulating cell macropinocytosis. In addition, cell exocytosis can be induced and/or modulated in the presence of βγ-CAT. Depending on cell contexts and surroundings, these effects can facilitate the toad in material uptake and vesicular transport, while maintaining mucosal barrier function as well as immune defense. Based on experimental evidence, we hereby propose a secretory endolysosome channel (SELC) pathway conducted by a secreted PFP in cell endocytic and exocytic systems, with βγ-CAT being the first example of a SELC protein. With essential roles in cell interactions and environmental adaptations, the proposed SELC protein pathway should be conserved in other living organisms.
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Affiliation(s)
- Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan 650223, China. E-mail:
| | - Qi-Quan Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Zhong Zhao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
| | - Cheng-Jie Deng
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China
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2
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Wang Q, Bian X, Zeng L, Pan F, Liu L, Liang J, Wang L, Zhou K, Lee W, Xiang Y, Li S, Teng M, Li X, Guo X, Zhang Y. A cellular endolysosome-modulating pore-forming protein from a toad is negatively regulated by its paralog under oxidizing conditions. J Biol Chem 2020; 295:10293-10306. [PMID: 32499370 DOI: 10.1074/jbc.ra120.013556] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 05/22/2020] [Indexed: 01/05/2023] Open
Abstract
Endolysosomes are key players in cell physiology, including molecular exchange, immunity, and environmental adaptation. They are the molecular targets of some pore-forming aerolysin-like proteins (ALPs) that are widely distributed in animals and plants and are functionally related to bacterial toxin aerolysins. βγ-CAT is a complex of an ALP (BmALP1) and a trefoil factor (BmTFF3) in the firebelly toad (Bombina maxima). It is the first example of a secreted endogenous pore-forming protein that modulates the biochemical properties of endolysosomes by inducing pore formation in these intracellular vesicles. Here, using a large array of biochemical and cell biology methods, we report the identification of BmALP3, a paralog of BmALP1 that lacks membrane pore-forming capacity. We noted that both BmALP3 and BmALP1 contain a conserved cysteine in their C-terminal regions. BmALP3 was readily oxidized to a disulfide bond-linked homodimer, and this homodimer then oxidized BmALP1 via disulfide bond exchange, resulting in the dissociation of βγ-CAT subunits and the elimination of biological activity. Consistent with its behavior in vitro, BmALP3 sensed environmental oxygen tension in vivo, leading to modulation of βγ-CAT activity. Interestingly, we found that this C-terminal cysteine site is well conserved in numerous vertebrate ALPs. These findings uncover the existence of a regulatory ALP (BmALP3) that modulates the activity of an active ALP (BmALP1) in a redox-dependent manner, a property that differs from those of bacterial toxin aerolysins.
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Affiliation(s)
- Qiquan Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xianling Bian
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Lin Zeng
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Fei Pan
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Lingzhen Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jinyang Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Lingyan Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Kaifeng Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Wenhui Lee
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yang Xiang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Sheng'an Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Maikun Teng
- Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Xu Li
- Hefei National Laboratory for Physical Sciences at Microscale, Innovation Center for Cell Signaling Network, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China
| | - Xiaolong Guo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China .,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan, China
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3
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Guo XL, Liu LZ, Wang QQ, Liang JY, Lee WH, Xiang Y, Li SA, Zhang Y. Endogenous pore-forming protein complex targets acidic glycosphingolipids in lipid rafts to initiate endolysosome regulation. Commun Biol 2019; 2:59. [PMID: 30775460 PMCID: PMC6370762 DOI: 10.1038/s42003-019-0304-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 01/08/2019] [Indexed: 12/23/2022] Open
Abstract
Bacterial pore-forming toxin aerolysin-like proteins (ALPs) are widely distributed in animals and plants. However, functional studies on these ALPs remain in their infancy. βγ-CAT is the first example of a secreted pore-forming protein that functions to modulate the endolysosome pathway via endocytosis and pore formation on endolysosomes. However, the specific cell surface molecules mediating the action of βγ-CAT remain elusive. Here, the actions of βγ-CAT were largely attenuated by either addition or elimination of acidic glycosphingolipids (AGSLs). Further study revealed that the ALP and trefoil factor (TFF) subunits of βγ-CAT bind to gangliosides and sulfatides, respectively. Additionally, disruption of lipid rafts largely impaired the actions of βγ-CAT. Finally, the ability of βγ-CAT to clear pathogens was attenuated in AGSL-eliminated frogs. These findings revealed a previously unknown double binding pattern of an animal-secreted ALP in complex with TFF that initiates ALP-induced endolysosomal pathway regulation, ultimately leading to effective antimicrobial responses.
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Affiliation(s)
- Xiao-Long Guo
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Ling-Zhen Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, 650204, China
| | - Qi-Quan Wang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, 650204, China
| | - Jin-Yang Liang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, 650204, China
| | - Wen-Hui Lee
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Yang Xiang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China
| | - Sheng-An Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
| | - Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, 650223, China. .,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan, 650223, China.
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4
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Gao Q, Xiang Y, Chen Z, Zeng L, Ma X, Zhang Y. βγ-CAT, a non-lens betagamma-crystallin and trefoil factor complex, induces calcium-dependent platelet apoptosis. Thromb Haemost 2017; 105:846-54. [DOI: 10.1160/th10-10-0690] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 01/29/2011] [Indexed: 11/05/2022]
Abstract
SummaryIn recent years, it has been reported that apoptosis may occur in platelets and play a role in the clearance of effete platelets. βγ-CAT, a newly identified non-lens βγ-crystallin and trefoil factor complex from frog Bombina maxima skin secretions, caused several in vivo toxic effects on mammals. Through determined haematological parameters of rabbits, it has been found that βγ-CAT significantly reduced the number of platelets in a time-dependent manner. Here, in order to explore the effect of βγ-CAT on platelets, washed platelets were incubated with various concentrations of βγ-CAT for 30 minutes. We found that βγ-CAT induced several apoptosis events in human platelets, including caspase-3 activation, phosphatidylserine (PS) exposure, depolarisation of mitochondrial inner transmembrane potential (ΔΨm), cytochrome c re-lease and strong expression of pro-apoptotic Bax and Bak proteins. However, βγ-CAT did not significantly induce platelet activation as detected by P-selectin surface expression, GPIIb/IIIa activation and platelet aggregation. In addition, we observed that βγ-CAT-induced PS exposure and ΔΨm depolarisation in platelets are Ca2+-dependent. Taken together, βγ-CAT can induce Ca2+-dependent platelet apoptosis but does not cause platelet activation.
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Host-derived, pore-forming toxin-like protein and trefoil factor complex protects the host against microbial infection. Proc Natl Acad Sci U S A 2014; 111:6702-7. [PMID: 24733922 DOI: 10.1073/pnas.1321317111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Aerolysins are virulence factors belonging to the bacterial β-pore-forming toxin superfamily. Surprisingly, numerous aerolysin-like proteins exist in vertebrates, but their biological functions are unknown. βγ-CAT, a complex of an aerolysin-like protein subunit (two βγ-crystallin domains followed by an aerolysin pore-forming domain) and two trefoil factor subunits, has been identified in frogs (Bombina maxima) skin secretions. Here, we report the rich expression of this protein, in the frog blood and immune-related tissues, and the induction of its presence in peritoneal lavage by bacterial challenge. This phenomena raises the possibility of its involvement in antimicrobial infection. When βγ-CAT was administrated in a peritoneal infection model, it greatly accelerated bacterial clearance and increased the survival rate of both frogs and mice. Meanwhile, accelerated Interleukin-1β release and enhanced local leukocyte recruitments were determined, which may partially explain the robust and effective antimicrobial responses observed. The release of interleukin-1β was potently triggered by βγ-CAT from the frog peritoneal cells and murine macrophages in vitro. βγ-CAT was rapidly endocytosed and translocated to lysosomes, where it formed high molecular mass SDS-stable oligomers (>170 kDa). Lysosomal destabilization and cathepsin B release were detected, which may explain the activation of caspase-1 inflammasome and subsequent interleukin-1β maturation and release. To our knowledge, these results provide the first functional evidence of the ability of a host-derived aerolysin-like protein to counter microbial infection by eliciting rapid and effective host innate immune responses. The findings will also largely help to elucidate the possible involvement and action mechanisms of aerolysin-like proteins and/or trefoil factors widely existing in vertebrates in the host defense against pathogens.
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Mishra A, Krishnan B, Srivastava SS, Sharma Y. Microbial βγ-crystallins. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:42-51. [PMID: 24594023 DOI: 10.1016/j.pbiomolbio.2014.02.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 01/24/2023]
Abstract
βγ-Crystallins have emerged as a superfamily of structurally homologous proteins with representatives across the domains of life. A major portion of this superfamily is constituted by members from microorganisms. This superfamily has also been recognized as a novel group of Ca(2+)-binding proteins with huge diversity. The βγ domain shows variable properties in Ca(2+) binding, stability and association with other domains. The various members present a series of evolutionary adaptations culminating in great diversity in properties and functions. Most of the predicted βγ-crystallins are yet to be characterized experimentally. In this review, we outline the distinctive features of microbial βγ-crystallins and their position in the βγ-crystallin superfamily.
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Affiliation(s)
- Amita Mishra
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India
| | - Bal Krishnan
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India
| | | | - Yogendra Sharma
- CSIR - Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500 007, India.
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7
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Srivastava SS, Mishra A, Krishnan B, Sharma Y. Ca2+-binding motif of βγ-crystallins. J Biol Chem 2014; 289:10958-10966. [PMID: 24567326 DOI: 10.1074/jbc.o113.539569] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
βγ-Crystallin-type double clamp (N/D)(N/D)XX(S/T)S motif is an established but sparsely investigated motif for Ca(2+) binding. A βγ-crystallin domain is formed of two Greek key motifs, accommodating two Ca(2+)-binding sites. βγ-Crystallins make a separate class of Ca(2+)-binding proteins (CaBP), apparently a major group of CaBP in bacteria. Paralleling the diversity in βγ-crystallin domains, these motifs also show great diversity, both in structure and in function. Although the expression of some of them has been associated with stress, virulence, and adhesion, the functional implications of Ca(2+) binding to βγ-crystallins in mediating biological processes are yet to be elucidated.
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Affiliation(s)
- Shanti Swaroop Srivastava
- Centre for Cellular and Molecular Biology (CCMB), Council of Scientific and Industrial Research (CSIR), Uppal Road, Hyderabad-500 007, India
| | - Amita Mishra
- Centre for Cellular and Molecular Biology (CCMB), Council of Scientific and Industrial Research (CSIR), Uppal Road, Hyderabad-500 007, India
| | - Bal Krishnan
- Centre for Cellular and Molecular Biology (CCMB), Council of Scientific and Industrial Research (CSIR), Uppal Road, Hyderabad-500 007, India
| | - Yogendra Sharma
- Centre for Cellular and Molecular Biology (CCMB), Council of Scientific and Industrial Research (CSIR), Uppal Road, Hyderabad-500 007, India.
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Zhao H, Brown PH, Magone MT, Schuck P. The molecular refractive function of lens γ-Crystallins. J Mol Biol 2011; 411:680-99. [PMID: 21684289 PMCID: PMC3146585 DOI: 10.1016/j.jmb.2011.06.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/01/2011] [Accepted: 06/02/2011] [Indexed: 10/18/2022]
Abstract
γ-Crystallins constitute the major protein component in the nucleus of the vertebrate eye lens. Present at very high concentrations, they exhibit extreme solubility and thermodynamic stability to prevent scattering of light and formation of cataracts. However, functions beyond this structural role have remained mostly unclear. Here, we calculate molecular refractive index increments of crystallins. We show that all lens γ-crystallins have evolved a significantly elevated molecular refractive index increment, which is far above those of most proteins, including nonlens members of the βγ-crystallin family from different species. The same trait has evolved in parallel in crystallins of different phyla, including S-crystallins of cephalopods. A high refractive index increment can lower the crystallin concentration required to achieve a suitable refractive power of the lens and thereby reduce their propensity to aggregate and form cataracts. To produce a significant increase in the refractive index increment, a substantial global shift in amino acid composition is required, which can naturally explain the highly unusual amino acid composition of γ-crystallins and their functional homologues. This function provides a new perspective for interpreting their molecular structure.
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Affiliation(s)
- Huaying Zhao
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, U.S.A
| | - Patrick H. Brown
- Biomedical Engineering and Physical Sciences Shared Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, U.S.A
| | - M. Teresa Magone
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, U.S.A
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, U.S.A
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9
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Gao Q, Xiang Y, Zeng L, Ma XT, Lee WH, Zhang Y. Characterization of the βγ-crystallin domains of βγ-CAT, a non-lens βγ-crystallin and trefoil factor complex, from the skin of the toad Bombina maxima. Biochimie 2011; 93:1865-72. [PMID: 21784123 DOI: 10.1016/j.biochi.2011.07.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 07/06/2011] [Indexed: 12/15/2022]
Abstract
βγ-CAT is a naturally existing 72-kDa complex of a non-lens βγ-crystallin (α-subunit, CAT-α) and a trefoil factor (β-subunit, CAT-β) that contains a non-covalently linked form of αβ(2) and was isolated from the skin secretions of the toad Bombina maxima. The N-terminal region of CAT-α (CAT-αN, residues 1-170) contains two βγ-crystallin domains while the C-terminal region (CAT-αC) has sequence homology to the membrane insertion domain of the Clostridium perfringens epsilon toxin. To examine the biochemical characteristics of the βγ-crystallin domains of βγ-CAT, CAT-αN, CAT-αC and CAT-β were expressed in Escherichia coli. Co-immunoprecipitation of the naturally assembled βγ-CAT confirmed that the CAT-α and CAT-β complex always exists. Furthermore, recombinant CAT-β bound recombinant CAT-αN. Ca(2+)-binding motifs were identified in CAT-αN, and recombinant CAT-αN was able to bind the calcium probe terbium. However, the conformation of CAT-αN was not significantly altered upon Ca(2+) binding. βγ-CAT possesses strong hemolytic activity toward human erythrocytes, and treatment of erythrocytes with βγ-CAT resulted in a rapid Ca(2+) influx, eventually leading to hemolysis. However, in the absence of extracellular Ca(2+), no significant hemolysis was detected, even though the binding and oligomerization of βγ-CAT in the erythrocyte membrane was observed. Our data demonstrate the binding of CAT-β (a trefoil factor) to CAT-αN (βγ-crystallin domains) and provide a basis for the formation of a βγ-crystallin and trefoil factor complex in vivo. Furthermore, the βγ-crystallin domains of βγ-CAT are able to bind Ca(2+), and βγ-CAT-induced hemolysis is Ca(2+) dependent.
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Affiliation(s)
- Qian Gao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences, Kunming Institute of Zoology, The Chinese Academy of Sciences, 32 East Jiao Chang Road, Kunming 650223, China
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10
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Szczesny P, Iacovache I, Muszewska A, Ginalski K, van der Goot FG, Grynberg M. Extending the aerolysin family: from bacteria to vertebrates. PLoS One 2011; 6:e20349. [PMID: 21687664 PMCID: PMC3110756 DOI: 10.1371/journal.pone.0020349] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 04/29/2011] [Indexed: 11/18/2022] Open
Abstract
A number of bacterial virulence factors have been observed to adopt structures similar to that of aerolysin, the principal toxin of Aeromonas species. However, a comprehensive description of architecture and structure of the aerolysin-like superfamily has not been determined. In this study, we define a more compact aerolysin-like domain--or aerolysin fold--and show that this domain is far more widely spread than anticipated since it can be found throughout kingdoms. The aerolysin-fold could be found in very diverse domain and functional contexts, although a toxic function could often be assigned. Due to this diversity, the borders of the superfamily could not be set on a sequence level. As a border-defining member, we therefore chose pXO2-60--a protein from the pathogenic pXO2 plasmid of Bacillus anthracis. This fascinating protein, which harbors a unique ubiquitin-like fold domain at the C-terminus of the aerolysin-domain, nicely illustrates the diversity of the superfamily. Its putative role in the virulence of B. anthracis and its three dimensional model are discussed.
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Affiliation(s)
- Pawel Szczesny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Experimental Plant Biology, University of Warsaw, Warsaw, Poland
| | - Ioan Iacovache
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Ginalski
- Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Warsaw, Poland
| | - F. Gisou van der Goot
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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Laetiporus sulphureus lectin and aerolysin protein family. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 677:67-80. [PMID: 20687481 DOI: 10.1007/978-1-4419-6327-7_6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The parasitic mushroom Laetiporus sulphureus produces a family of lectins (LSL's) sharing 80-90% sequence identity that possesses a low but significant sequence similarity to the bacterial pore-forming toxins mosquitocidal toxin Mtx-2 from Bacillus sphaericus and a toxin from Clostridium septicum. The crystal structure of one member of the L. sulphureus lectins family (LSLa) reveals unexpected structural similarities to the 1-pore-forming toxins from the aerolysin family, namely, aerolysin from the Gram-negative bacterium Aeromonas hydrophila, epsilon-toxin from Clostridium perfringens and parasporin from B. thuringiensis. This similarity presumably indicates that the hemolytic activity of LSLa proceeds through a molecular mechanism that involves the formation of oligomeric transmembrane beta-barrels. Comparison of the crystal structures of the above mentioned proteins reveals common pore-forming modules, which are then distributed both in bacteria and fungi. Currently, it can be stated that the above three dimensional structures have been key in revealing structural similarities that were elusive at the sequence level. A potential corollary from this is that structural studies aimed at determining high resolution structures of aerolysin-like pore-forming toxins, whose biological activity involves large conformational changes, are mandatory to define protein domains or structural motifs with membrane-binding properties.
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12
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LIU SB, HE YY, QIAN JQ, LEE WH, ZHANG Y. Research Progression of Non-lens βγ-crystallins. Zool Res 2009. [DOI: 10.3724/sp.j.1141.2008.06679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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13
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Weadick CJ, Chang BSW. Molecular evolution of the betagamma lens crystallin superfamily: evidence for a retained ancestral function in gamma N crystallins? Mol Biol Evol 2009; 26:1127-42. [PMID: 19233964 DOI: 10.1093/molbev/msp028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Within the vertebrate eye, betagamma crystallins are extremely stable lens proteins that are uniquely adapted to increase refractory power while maintaining transparency. Unlike alpha crystallins, which are well-characterized, multifunctional proteins that have important functions both in and out of the lens, betagamma lens crystallins are a diverse group of proteins with no clear ancestral or contemporary nonlens role. We carried out phylogenetic and molecular evolutionary analyses of the betagamma-crystallin superfamily in order to study the evolutionary history of the gamma N crystallins, a recently discovered, biochemically atypical family suggested to possess a divergent or ancestral function. By including nonlens, betagamma-motif-containing sequences in our analysis as outgroups, we confirmed the phylogenetic position of the gamma N family as sister to other gamma crystallins. Using maximum likelihood codon models to estimate lineage-specific nonsynonymous-to-synonymous rate ratios revealed strong positive selection in all of the early lineages within the betagamma family, with the striking exception of the lineage leading to the gamma N crystallins which was characterized by strong purifying selection. Branch-site analysis, used to identify candidate sites involved in functional divergence between gamma N crystallins and its sister clade containing all other gamma crystallins, identified several positively selected changes at sites of known functional importance in the betagamma crystallin protein structure. Further analyses of a fish-specific gamma N crystallin gene duplication revealed a more recent episode of positive selection in only one of the two descendant lineages (gamma N2). Finally, from the guppy, Poecilia reticulata, we isolated complete gamma N1 and gamma N2 coding sequence data from cDNA and partial coding sequence data from genomic DNA in order to confirm the presence of a novel gamma N2 intron, discovered through data mining of two pufferfish genomes. We conclude that the function of the gamma N family likely resembles the ancestral vertebrate betagamma crystallin more than other betagamma families. Furthermore, owing to the presence of an additional intron in some fish gamma N2 crystallins, and the inferred action of positive selection following the fish-specific gamma N duplication, we suggest that further study of fish gamma N crystallins will be critical in further elucidating possible ancestral functions of gamma N crystallins and any nonstructural role they may have.
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Affiliation(s)
- Cameron J Weadick
- Department of Ecology and Evolution, University of Toronto, Toronto, Ontario, Canada
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He YY, Liu SB, Lee WH, Zhang Y. Melanoma cell growth inhibition by βγ-CAT, which is a novel non-lens betagamma-crystallin and trefoil factor complex from frog Bombina maxima skin. Toxicon 2008; 52:341-7. [DOI: 10.1016/j.toxicon.2008.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2008] [Revised: 06/05/2008] [Accepted: 06/06/2008] [Indexed: 01/23/2023]
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βγ-CAT, a non-lens βγ-crystallin and trefoil factor complex from amphibian skin secretions, caused endothelium-dependent myocardial depression in isolated rabbit hearts. Toxicon 2008; 52:285-92. [DOI: 10.1016/j.toxicon.2008.05.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 05/21/2008] [Accepted: 05/28/2008] [Indexed: 11/18/2022]
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Qian JQ, Liu SB, He YY, Lee WH, Zhang Y. Acute toxicity of βγ-CAT, a naturally existing non-lens βγ-crystallin and trefoil factor complex from frog Bombina maxima skin secretions. Toxicon 2008; 52:22-31. [DOI: 10.1016/j.toxicon.2008.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 05/04/2008] [Accepted: 05/06/2008] [Indexed: 01/12/2023]
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Liu SB, He YY, Zhang Y, Lee WH, Qian JQ, Lai R, Jin Y. A novel non-lens betagamma-crystallin and trefoil factor complex from amphibian skin and its functional implications. PLoS One 2008; 3:e1770. [PMID: 18335045 PMCID: PMC2262142 DOI: 10.1371/journal.pone.0001770] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Accepted: 02/07/2008] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND In vertebrates, non-lens betagamma-crystallins are widely expressed in various tissues, but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained elusive. PRINCIPAL FINDINGS A naturally existing 72-kDa complex of non-lens betagamma-crystallin (alpha-subunit) and trefoil factor (beta-subunit), named betagamma-CAT, was identified from frog Bombina maxima skin secretions. Its alpha-subunit and beta-subunit (containing three trefoil factor domains), with a non-covalently linked form of alphabeta(2), show significant sequence homology to ep37 proteins, a group of non-lens betagamma-crystallins identified in newt Cynops pyrrhogaster and mammalian trefoil factors, respectively. betagamma-CAT showed potent hemolytic activity on mammalian erythrocytes. The specific antiserum against each subunit was able to neutralize its hemolytic activity, indicating that the two subunits are functionally associated. betagamma-CAT formed membrane pores with a functional diameter about 2.0 nm, leading to K(+) efflux and colloid-osmotic hemolysis. High molecular weight SDS-stable oligomers (>240-kDa) were detected by antibodies against the alpha-subunit with Western blotting. Furthermore, betagamma-CAT showed multiple cellular effects on human umbilical vein endothelial cells. Low dosages of betagamma-CAT (25-50 pM) were able to stimulate cell migration and wound healing. At high concentrations, it induced cell detachment (EC(50) 10 nM) and apoptosis. betagamma-CAT was rapidly endocytosed via intracellular vacuole formation. Under confocal microscope, some of the vacuoles were translocated to nucleus and partially fused with nuclear membrane. Bafilomycin A1 (a specific inhibitor of the vacuolar-type ATPase) and nocodazole (an agent of microtuble depolymerizing), while inhibited betagamma-CAT induced vacuole formation, significantly inhibited betagamma-CAT induced cell detachment, suggesting that betagamma-CAT endocytosis is important for its activities. CONCLUSIONS/SIGNIFICANCE These findings illustrate novel cellular functions of non-lens betagamma-cyrstallins and action mechanism via association with trefoil factors, serving as clues for investigating the possible occurrence of similar molecules and action mechanisms in mammals.
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Affiliation(s)
- Shu-Bai Liu
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Ying-Ying He
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Yun Zhang
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Wen-Hui Lee
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jin-Qiao Qian
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
- Graduate School of the Chinese Academy of Sciences, Beijing, China
| | - Ren Lai
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Yang Jin
- Biotoxin Units, Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, Yunnan, China
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Abstract
Betagamma-crystallin is a superfamily with diverse members from vertebrate lens to microbes. However, not many members have been identified and studied. Here, we report the identification of a putative exported protein from Yersinia pestis as a member of the betagamma-crystallin superfamily. Even though calcium has been known to play an important role in the physiology and virulence of the Yersinia genus, calcium-binding proteins have not yet been identified. We have studied the calcium-binding properties of two of the three crystallin domains present in this putative exported protein designated "Yersinia crystallin." These two domains (D1 and D2) have unique AA and BB types of arrangement of their Greek key motifs unlike the domains of other members of the betagamma-crystallin superfamily, which are either AB or BA types. These domains bind two calcium ions with low and high affinity-binding sites. We showed their calcium-binding properties using various probes for calcium and the effect of calcium on their secondary and tertiary structures. Although both domains bind calcium, D1 underwent drastic changes in secondary and tertiary structure and hydrodynamic volume upon calcium binding. Domain D1, which is intrinsically unstructured in the apo form, requires calcium for the typical betagamma-crystallin fold. Calcium exerted an extrinsic stabilization effect on domain D1 but not on D2, which is also largely unstructured. We suggest that this protein might be involved in calcium-dependent processes, such as stress response or physiology in the Yersinia genus, similar to its microbial relatives and mammalian lens crystallins.
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Affiliation(s)
- Maroor K Jobby
- Center for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India
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Rajini B, Shridas P, Sundari CS, Muralidhar D, Chandani S, Thomas F, Sharma Y. Calcium binding properties of gamma-crystallin: calcium ion binds at the Greek key beta gamma-crystallin fold. J Biol Chem 2001; 276:38464-71. [PMID: 11502736 DOI: 10.1074/jbc.m102164200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The beta- and gamma-crystallins are closely related lens proteins that are members of the betagamma-crystallin superfamily, which also include many non-lens members. Although beta-crystallin is known to be a calcium-binding protein, this property has not been reported in gamma-crystallin. We have studied the calcium binding properties of gamma-crystallin, and we show that it binds 4 mol eq of calcium with a dissociation constant of 90 microm. It also binds the calcium-mimic spectral probes, terbium and Stains-all. Calcium binding does not significantly influence protein secondary and tertiary structures. We present evidence that the Greek key crystallin fold is the site for calcium ion binding in gamma-crystallin. Peptides corresponding to Greek key motif of gamma-crystallin (42 residues) and their mutants were synthesized and studied for calcium binding. These peptides adopt beta-sheet conformation and form aggregates producing beta-sandwich. Our results with peptides show that, in Greek key motif, the amino acid adjacent to the conserved aromatic corner in the "a" strand and three amino acids of the "d" strand participate in calcium binding. We suggest that the betagamma superfamily represents a novel class of calcium-binding proteins with the Greek key betagamma-crystallin fold as potential calcium-binding sites. These results are of significance in understanding the mechanism of calcium homeostasis in the lens.
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Affiliation(s)
- B Rajini
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad-500007, India
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