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Gu QY, Liu YX, Wang JL, Huang XL, Li RN, Linghu H. LLGL2 Inhibits Ovarian Cancer Metastasis by Regulating Cytoskeleton Remodeling via ACTN1. Cancers (Basel) 2023; 15:5880. [PMID: 38136424 PMCID: PMC10742334 DOI: 10.3390/cancers15245880] [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: 10/19/2023] [Revised: 12/09/2023] [Accepted: 12/10/2023] [Indexed: 12/24/2023] Open
Abstract
Epithelial ovarian cancer is the most lethal gynecological malignant tumor. Although debulking surgery, chemotherapy, and PARP inhibitors have greatly improved survival, the prognosis for patients with advanced EOC without HRD is still poor. LLGL2, as a cell polarity factor, is involved in maintaining cell polarity and asymmetric cell division. In the study of zebrafish development, LLGL2 regulated the proliferation and migration of epidermal cells and the formation of cortical F-actin. However, the role of LLGL2 in ovarian cancer has not been described. Our study found, through bioinformatics analysis, that low expression of LLGL2 was significantly associated with a more advanced stage and a higher grade of EOC and a poorer survival of patients. Functional experiments that involved LLGL2 overexpression and knockdown showed that LLGL2 inhibited the migration and invasion abilities of ovarian cancer cells in vitro, without affecting their proliferation. LLGL2-overexpressing mice had fewer metastatic implant foci than the controls in vivo. Mechanistically, immunoprecipitation combined with mass spectrometry analysis suggested that LLGL2 regulated cytoskeletal remodeling by interacting with ACTN1. LLGL2 altered the intracellular localization and function of ACTN1 without changing its protein and mRNA levels. Collectively, we uncovered that LLGL2 impaired actin filament aggregation into bundles by interacting with ACTN1, which led to cytoskeleton remodeling and inhibition of the invasion and metastasis of ovarian cancer cells.
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Affiliation(s)
| | | | | | | | - Ruo-Nan Li
- Department of Gynecology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; (Q.-Y.G.); (Y.-X.L.); (J.-L.W.); (X.-L.H.)
| | - Hua Linghu
- Department of Gynecology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; (Q.-Y.G.); (Y.-X.L.); (J.-L.W.); (X.-L.H.)
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2
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Bii VM, Rudoy D, Klezovitch O, Vasioukhin V. Lethal giant larvae gene family ( Llgl1 and Llgl2 ) functions as a tumor suppressor in mouse skin epidermis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531408. [PMID: 36945368 PMCID: PMC10028895 DOI: 10.1101/2023.03.06.531408] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Loss of cell polarity and tissue disorganization occurs in majority of epithelial cancers. Studies in simple model organisms identified molecular mechanisms responsible for the establishment and maintenance of cellular polarity, which play a pivotal role in establishing proper tissue architecture. The exact role of these cell polarity pathways in mammalian cancer is not completely understood. Here we analyzed the mammalian orthologs of drosophila apical-basal polarity gene lethal giant larvae ( lgl ), which regulates asymmetric stem cell division and functions as a tumor suppressor in flies. There are two mammalian orthologs of lgl ( Llgl1 and Llgl2 ). To determine the role of the entire lgl signaling pathway in mammals we generated mice with ablation of both Llgl1 and Llgl2 in skin epidermis using K14-Cre ( Llgl1/2 -/- cKO mice). Surprisingly, we found that ablation of Llgl1/2 genes does not impact epidermal polarity in adult mice. However, old Llgl1/2 cKO mice present with focal skin lesions which are missing epidermal layer and ripe with inflammation. To determine the role of lgl signaling pathway in cancer we generated Trp53 -/- /Llgl1/2 -/- cKO and Trp53 -/+ /Llgl1/2 -/- cKO mice. Loss of Llgl1/2 promoted squamous cell carcinoma (SCC) development in Trp53 -/- cKO and caused SCC in Trp53 -/+ cKO mice, while no cancer was observed in Trp53 -/+ cKO controls. Mechanistically, we show that ablation of Llgl1/2 causes activation of aPKC and upregulation of NF-kB signaling pathway, which may be necessary for SCC in Trp53 -/+ /Llgl1/2 -/- cKO mice. We conclude that Lgl signaling pathway functions as a tumor suppressor in mammalian skin epidermis.
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Shi X, Liu X, Silver K, Zhu KY, Zhang J. Lethal giant larvae gene is required for normal nymphal development and midgut morphogenesis in Locusta migratoria. INSECT SCIENCE 2022; 29:1017-1029. [PMID: 34978756 DOI: 10.1111/1744-7917.12996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 11/18/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
Disruption of morphogenesis, an essential process in organismal development, can lead to disruption of biological processes, reduction in fitness, or even death of an organism. The roles of lethal giant larvae (Lgl) protein in maintaining tissue organization have been studied extensively in mammals, but little is known about this gene's roles in promoting correct tissue morphogenesis in insects. In this study, we identified an Lgl ortholog in Locusta migratoria. RT-qPCR results revealed that LmLgl was constitutively expressed during third, fourth, and fifth instar nymphs. Furthermore, LmLgl showed highest expression in the ovary followed by wing pads, midgut, hindgut, Malpighian tubules, and foregut of the third-instar nymphs. To examine the role of LmLgl in L. migratoria development, RNA interference was performed during nymphal stages. Silencing of LmLgl increased body size but decreased bodyweight by 9.0%. Histological sections of the midgut revealed abnormal large masses of disordered epithelial cells in dsLmLgl-injected nymphs. In addition, downregulation of LmLgl transcript levels significantly altered the morphological structure in midgut, resulting in the formation of tumor-like structures. Our results indicated that LmLgl may act as a tumor-suppressor gene, which plays an essential role in maintaining a normal morphological structure in the midgut of L. migratoria. Our results also suggest that LmLgl may be explored as a potential target for developing dsRNA-based biological pesticides for managing insect pests.
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Affiliation(s)
- Xuekai Shi
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
- College of Life Science, Shanxi University, Taiyuan, Shanxi, China
| | - Xiaojian Liu
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Kristopher Silver
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Kun Yan Zhu
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Jianzhen Zhang
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
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4
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Ecovoiu AA, Ratiu AC, Micheu MM, Chifiriuc MC. Inter-Species Rescue of Mutant Phenotype—The Standard for Genetic Analysis of Human Genetic Disorders in Drosophila melanogaster Model. Int J Mol Sci 2022; 23:ijms23052613. [PMID: 35269756 PMCID: PMC8909942 DOI: 10.3390/ijms23052613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Drosophila melanogaster (the fruit fly) is arguably a superstar of genetics, an astonishing versatile experimental model which fueled no less than six Nobel prizes in medicine. Nowadays, an evolving research endeavor is to simulate and investigate human genetic diseases in the powerful D. melanogaster platform. Such a translational experimental strategy is expected to allow scientists not only to understand the molecular mechanisms of the respective disorders but also to alleviate or even cure them. In this regard, functional gene orthology should be initially confirmed in vivo by transferring human or vertebrate orthologous transgenes in specific mutant backgrounds of D. melanogaster. If such a transgene rescues, at least partially, the mutant phenotype, then it qualifies as a strong candidate for modeling the respective genetic disorder in the fruit fly. Herein, we review various examples of inter-species rescue of relevant mutant phenotypes of the fruit fly and discuss how these results recommend several human genes as candidates to study and validate genetic variants associated with human diseases. We also consider that a wider implementation of this evolutionist exploratory approach as a standard for the medicine of genetic disorders would allow this particular field of human health to advance at a faster pace.
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Affiliation(s)
- Alexandru Al. Ecovoiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
| | - Attila Cristian Ratiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
- Correspondence: ; Tel.: +40-722250366
| | - Miruna Mihaela Micheu
- Department of Cardiology, Clinical Emergency Hospital of Bucharest, 014461 Bucharest, Romania;
| | - Mariana Carmen Chifiriuc
- The Research Institute of the University of Bucharest and Faculty of Biology, University of Bucharest, 050095 Bucharest, Romania;
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Tocan V, Hayase J, Kamakura S, Kohda A, Ohga S, Kohjima M, Sumimoto H. Hepatocyte polarity establishment and apical lumen formation are organized by Par3, Cdc42, and aPKC in conjunction with Lgl. J Biol Chem 2021; 297:101354. [PMID: 34717957 PMCID: PMC8637150 DOI: 10.1016/j.jbc.2021.101354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/17/2021] [Accepted: 10/19/2021] [Indexed: 01/21/2023] Open
Abstract
Hepatocytes differ from columnar epithelial cells by their multipolar organization, which follows the initial formation of central lumen-sharing clusters of polarized cells as observed during liver development and regeneration. The molecular mechanism for hepatocyte polarity establishment, however, has been comparatively less studied than those for other epithelial cell types. Here, we show that the tight junction protein Par3 organizes hepatocyte polarization via cooperating with the small GTPase Cdc42 to target atypical protein kinase C (aPKC) to a cortical site near the center of cell-cell contacts. In 3D Matrigel culture of human hepatocytic HepG2 cells, which mimics a process of liver development and regeneration, depletion of Par3, Cdc42, or aPKC results in an impaired establishment of apicobasolateral polarity and a loss of subsequent apical lumen formation. The aPKC activity is also required for bile canalicular (apical) elongation in mouse primary hepatocytes. The lateral membrane-associated proteins Lgl1 and Lgl2, major substrates of aPKC, seem to be dispensable for hepatocyte polarity establishment because Lgl-depleted HepG2 cells are able to form a single apical lumen in 3D culture. On the other hand, Lgl depletion leads to lateral invasion of aPKC, and overexpression of Lgl1 or Lgl2 prevents apical lumen formation, indicating that they maintain proper lateral integrity. Thus, hepatocyte polarity establishment and apical lumen formation are organized by Par3, Cdc42, and aPKC; Par3 cooperates with Cdc42 to recruit aPKC, which plays a crucial role in apical membrane development and regulation of the lateral maintainer Lgl.
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Affiliation(s)
- Vlad Tocan
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Junya Hayase
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Sachiko Kamakura
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Akira Kohda
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Shouichi Ohga
- Department of Pediatrics, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Motoyuki Kohjima
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan; Department of Medicine and Regulatory Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Hideki Sumimoto
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
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6
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Lavictoire SJ, Jomaa D, Gont A, Jardine K, Cook DP, Lorimer IAJ. Identification of Rac guanine nucleotide exchange factors promoting Lgl1 phosphorylation in glioblastoma. J Biol Chem 2021; 297:101172. [PMID: 34624316 PMCID: PMC8551657 DOI: 10.1016/j.jbc.2021.101172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 08/25/2021] [Accepted: 09/03/2021] [Indexed: 11/23/2022] Open
Abstract
The protein Lgl1 is a key regulator of cell polarity. We previously showed that Lgl1 is inactivated by hyperphosphorylation in glioblastoma as a consequence of PTEN tumour suppressor loss and aberrant activation of the PI 3-kinase pathway; this contributes to glioblastoma pathogenesis both by promoting invasion and repressing glioblastoma cell differentiation. Lgl1 is phosphorylated by atypical protein kinase C that has been activated by binding to a complex of the scaffolding protein Par6 and active, GTP-bound Rac. The specific Rac guanine nucleotide exchange factors that generate active Rac to promote Lgl1 hyperphosphorylation in glioblastoma are unknown. We used CRISPR/Cas9 to knockout PREX1, a PI 3-kinase pathway-responsive Rac guanine nucleotide exchange factor, in patient-derived glioblastoma cells. Knockout cells had reduced Lgl1 phosphorylation, which was reversed by re-expressing PREX1. They also had reduced motility and an altered phenotype suggestive of partial neuronal differentiation; consistent with this, RNA-seq analyses identified sets of PREX1-regulated genes associated with cell motility and neuronal differentiation. PREX1 knockout in glioblastoma cells from a second patient did not affect Lgl1 phosphorylation. This was due to overexpression of a short isoform of the Rac guanine nucleotide exchange factor TIAM1; knockdown of TIAM1 in these PREX1 knockout cells reduced Lgl1 phosphorylation. These data show that PREX1 links aberrant PI 3-kinase signaling to Lgl1 phosphorylation in glioblastoma, but that TIAM1 is also to fill this role in a subset of patients. This redundancy between PREX1 and TIAM1 is only partial, as motility was impaired in PREX1 knockout cells from both patients.
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Affiliation(s)
- Sylvie J Lavictoire
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Danny Jomaa
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Alexander Gont
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Karen Jardine
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - David P Cook
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Ian A J Lorimer
- Cancer Therapeutics Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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7
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Cooper AMW, Song H, Shi X, Yu Z, Kim YH, Silver K, Zhang J, Zhu KY. Molecular characterization and RNA interference responses of the lethal giant larvae gene in Diabrotica virgifera virgifera adults. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2021; 107:e21787. [PMID: 33871104 DOI: 10.1002/arch.21787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
High specificity for silencing target genes and single-copy target genes that yield clear phenotypes are two important factors for the success of RNA interference (RNAi). The lethal giant larvae (Lgl) gene appears to be an ideal gene for RNAi because RNAi can effectively suppress its expression and results in molting defects and mortality in Tribolium castaneum. To investigate the suitability of this gene for RNAi in other insects, we identified and characterized DvLgl from the western corn rootworm, Diabrotica virgifera virgifera, a species exhibiting high RNAi efficiency. DvLgl was expressed in all developmental stages and tissues investigated. The deduced DvLgl protein showed high amino-acid sequence identities and similar domain architecture to Lgls from other insect species. Despite many similarities among insect Lgls, RNAi-mediated suppression of DvLgl failed to produce a phenotype in D. v. virgifera adults. The difference in developing phenotypes could be attributed greatly to the level of gene suppression and the insect developmental stages for RNAi. These results highlight the variability in RNAi response among insects and showcase the importance of screening multiple target genes when conducting RNAi studies. Our findings are expected to help the design of future RNAi studies and future investigations of Lgl in insects.
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Affiliation(s)
| | - Huifang Song
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Xuekai Shi
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Zhitao Yu
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Young Ho Kim
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
- Department of Applied Biology, Kyungpook National University, Sangju, Gyeongbuk, South Korea
| | - Kristopher Silver
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
| | - Jianzhen Zhang
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
- Institute of Applied Biology, Shanxi University, Taiyuan, Shanxi, China
| | - Kun Yan Zhu
- Department of Entomology, Kansas State University, Manhattan, Kansas, USA
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Nakajima YI. Scrib module proteins: Control of epithelial architecture and planar spindle orientation. Int J Biochem Cell Biol 2021; 136:106001. [PMID: 33962021 DOI: 10.1016/j.biocel.2021.106001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 01/15/2023]
Abstract
The Scrib module proteins, Scrib, Dlg, and Lgl, are conserved regulators of cell polarity in diverse biological contexts. Originally discovered as neoplastic tumor suppressors in the fruit fly Drosophila melanogaster, disruption of Scrib module components leads to tumorigenesis in mammalian epithelia and is associated with human cancers. With multiple protein interacting domains, Scrib module proteins function as determinants of basolateral identity in epithelial cells with apical-basal polarity while acting as signaling platform scaffold proteins. Recent studies have further revealed novel roles of the Scrib module in the control of epithelial architecture, ranging from polarity establishment and tricellular junction formation to planar spindle orientation during cell division. This review updates the current understanding of the molecular nature and physiological functions of the Scrib module with a focus on in vivo studies, providing a framework for how these protein dynamics affect the processes of epithelial organization.
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Affiliation(s)
- Yu-Ichiro Nakajima
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan; Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
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9
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The Role of pkc-3 and Genetic Suppressors in Caenorhabditis elegans Epithelial Cell Junction Formation. Genetics 2020; 214:941-959. [PMID: 32005655 DOI: 10.1534/genetics.120.303085] [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: 08/15/2019] [Accepted: 01/29/2020] [Indexed: 12/20/2022] Open
Abstract
Epithelial cells form intercellular junctions to strengthen cell-cell adhesion and limit diffusion, allowing epithelia to function as dynamic tissues and barriers separating internal and external environments. Junctions form as epithelial cells differentiate; clusters of junction proteins first concentrate apically, then mature into continuous junctional belts that encircle and connect each cell. In mammals and Drosophila, atypical protein kinase C (aPKC) is required for junction maturation, although how it contributes to this process is poorly understood. A role for the Caenorhabditis elegans aPKC homolog PKC-3 in junction formation has not been described previously. Here, we show that PKC-3 is essential for junction maturation as epithelia first differentiate. Using a temperature-sensitive allele of pkc-3 that causes junction breaks in the spermatheca and leads to sterility, we identify intragenic and extragenic suppressors that render pkc-3 mutants fertile. Intragenic suppressors include an unanticipated stop-to-stop mutation in the pkc-3 gene, providing evidence for the importance of stop codon identity in gene activity. One extragenic pkc-3 suppressor is a loss-of-function allele of the lethal(2) giant larvae homolog lgl-1, which antagonizes aPKC within epithelia of Drosophila and mammals, but was not known previously to function in C. elegans epithelia. Finally, two extragenic suppressors are loss-of-function alleles of sups-1-a previously uncharacterized gene. We show that SUPS-1 is an apical extracellular matrix protein expressed in epidermal cells, suggesting that it nonautonomously regulates junction formation in the spermatheca. These findings establish a foundation for dissecting the role of PKC-3 and interacting genes in epithelial junction maturation.
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New insights into apical-basal polarization in epithelia. Curr Opin Cell Biol 2019; 62:1-8. [PMID: 31505411 DOI: 10.1016/j.ceb.2019.07.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022]
Abstract
The establishment of an apical-basal axis of polarity is essential for the organization and functioning of epithelial cells. Polarization of epithelial cells is orchestrated by a network of conserved polarity regulators that establish opposing cortical domains through mutually antagonistic interactions and positive feedback loops. While our understanding is still far from complete, the molecular details behind these interactions continue to be worked out. Here, we highlight recent findings on the mechanisms that control the activity and localization of apical-basal polarity regulators, including oligomerization and higher-order complex formation, auto-inhibitory interactions, and electrostatic interactions with the plasma membrane.
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Ufimtsev IS, Almagor L, Weis WI, Levitt M. Solving the structure of Lgl2, a difficult blind test of unsupervised structure determination. Proc Natl Acad Sci U S A 2019; 116:10819-10823. [PMID: 31088964 PMCID: PMC6561170 DOI: 10.1073/pnas.1821513116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the companion paper by Ufimtsev and Levitt [Ufimtsev IS, Levitt M (2019) Proc Natl Acad Sci USA, 10.1073/pnas.1821512116], we presented a method for unsupervised solution of protein crystal structures and demonstrated its utility by solving several test cases of known structure in the 2.9- to 3.45-Å resolution range. Here we apply this method to solve the crystal structure of a 966-amino acid construct of human lethal giant larvae protein (Lgl2) that resisted years of structure determination efforts, at 3.2-Å resolution. The structure was determined starting with a molecular replacement (MR) model identified by unsupervised refinement of a pool of 50 candidate MR models. This initial model had 2.8-Å RMSD from the solution. The solved structure was validated by comparison with a model subsequently derived from an alternative crystal form diffracting to higher resolution. This model could phase an anomalous difference Fourier map from an Hg derivative, and a single-wavelength anomalous dispersion phased density map made from these sites aligned with the refined structure.
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Affiliation(s)
- Ivan S Ufimtsev
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Lior Almagor
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - William I Weis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Michael Levitt
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
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