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Wang W, Gao W, Zhang L, Zhang D, Zhao Z, Bao Y. [Retracted] Deoxypodophyllotoxin inhibits cell viability and invasion by blocking the PI3K/Akt signaling pathway in human glioblastoma cells. Oncol Rep 2023; 50:168. [PMID: 37503770 PMCID: PMC10394733 DOI: 10.3892/or.2023.8605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/18/2019] [Indexed: 07/29/2023] Open
Abstract
Following the publication of the above article and a corrigendum that was published to address issues of duplicated data panels in Fig. 4 (doi: 10.3892/or.2023.8484), a concerned reader has drawn to the Editor's attention that Fig. 3B also contains a matching pair of identical flow cytometry scatterplots where the results from different experiments were intended to have been portrayed, and certain of the western blotting data shown in Fig. 3C are strikingly similar to data that had appeared in Figs. 2 and 3 in a previously published paper written by different authors at different research institutes [Tian F, Ding D and Li D: Fangchinoline targets PI3K and suppresses PI3K/AKT signaling pathway in SGC7901 cells. Int J Oncol 46: 2355‑2363, 2015]. In view of the fact that certain of the data in the above article had already appeared in a previously published paper, and given the large number of apparently overlapping data panels identified in several of the figures, the Editor of Oncology Reports has decided that this paper should be retracted from the publication. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 41: 2453‑2463, 2019; DOI: 10.3892/or.2019.7016].
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Affiliation(s)
- Wei Wang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Wei Gao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Luyang Zhang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Dongyong Zhang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zilong Zhao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yijun Bao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Wang W, Gao W, Zhang L, Zhang D, Zhao Z, Bao Y. [Corrigendum] Deoxypodophyllotoxin inhibits cell viability and invasion by blocking the PI3K/Akt signaling pathway in human glioblastoma cells. Oncol Rep 2023; 49:47. [PMID: 36660948 PMCID: PMC9887462 DOI: 10.3892/or.2023.8484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 01/18/2019] [Indexed: 01/18/2023] Open
Abstract
Following the publication of the above article, a concerned reader drew to the authors' attention that various pairs of the data panels shown for the Transwell migration assays in Fig. 4A‑D on p. 2459 featured overlapping data, such that a number of the panels may have been derived from the same original sources. The authors have examined their original data, and realize that errors were inadvertently made during the assembly of these figure parts. The authors have reassembled Fig. 4 containing alternative data in Fig. 4A‑D, and the revised version of this figure is shown on the next page. Note that the revised data shown for this figure do not affect the overall conclusions reported in the paper. All the authors agree with the publication of this corrigendum, and are grateful to the Editor of 1 for allowing them the opportunity to publish this. They also apologize to the readership for any inconvenience caused. [Oncology Reports 41: 2453‑2463, 2019; DOI: 10.3892/or.2019.7016].
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Affiliation(s)
- Wei Wang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Wei Gao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Luyang Zhang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Dongyong Zhang
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zilong Zhao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yijun Bao
- Department of Neurosurgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Kato M, Tsuge T, Maeshima M, Aoyama T. Arabidopsis PCaP2 modulates the phosphatidylinositol 4,5-bisphosphate signal on the plasma membrane and attenuates root hair elongation. Plant J 2019; 99:610-625. [PMID: 30604455 DOI: 10.1111/tpj.14226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/12/2018] [Accepted: 12/17/2018] [Indexed: 05/22/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] serves as a subcellular signal on the plasma membrane, mediating various cell-polarized phenomena including polar cell growth. Here, we investigated the involvement of Arabidopsis thaliana PCaP2, a plant-unique plasma membrane protein with phosphoinositide-binding activity, in PtdIns(4,5)P2 signaling for root hair tip growth. The long-root-hair phenotype of the pcap2 knockdown mutant was found to stem from its higher average root hair elongation rate compared with the wild type and to counteract the low average rate caused by a defect in the PtdIns(4,5)P2 -producing enzyme gene PIP5K3. On the plasma membrane of elongating root hairs, the PCaP2 promoter-driven PCaP2-green fluorescent protein (GFP), which complemented the pcap2 mutant phenotype, overlapped with the PtdIns(4,5)P2 marker 2xCHERRY-2xPHPLC in the subapical region, but not at the apex, suggesting that PCaP2 attenuates root hair elongation via PtdIns(4,5)P2 signaling on the subapical plasma membrane. Consistent with this, a GFP fusion with the PCaP2 phosphoinositide-binding domain PCaP2N23 , root hair-specific overexpression of which caused a low average root hair elongation rate, localized more intense to the subapical plasma membrane than to the apical plasma membrane similar to PCaP2-GFP. Inducibly overexpressed PCaP2-GFP, but not its derivative lacking the PCaP2N23 domain, replaced 2xCHERRY-2xPHPLC on the plasma membrane in root meristematic epidermal cells, and suppressed FM4-64 internalization in elongating root hairs. Moreover, inducibly overexpressed PCaP2 arrested an endocytic process of PIN2-GFP recycling. Based on these results, we conclude that PCaP2 functions as a negative modulator of PtdIns(4,5)P2 signaling on the subapical plasma membrane probably through competitive binding to PtdIns(4,5)P2 and attenuates root hair elongation.
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Affiliation(s)
- Mariko Kato
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Masayoshi Maeshima
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya, Aichi, 464-8601, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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Mizutani N, Okochi Y, Okamura Y. Distinct functional properties of two electrogenic isoforms of the SLC34 Na-Pi cotransporter. Physiol Rep 2019; 7:e14156. [PMID: 31342668 PMCID: PMC6656865 DOI: 10.14814/phy2.14156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/02/2019] [Accepted: 05/03/2019] [Indexed: 01/05/2023] Open
Abstract
Inorganic phosphate (Pi ) is crucial for proper cellular function in all organisms. In mammals, type II Na-Pi cotransporters encoded by members of the Slc34 gene family play major roles in the maintenance of Pi homeostasis. However, the molecular mechanisms regulating Na-Pi cotransporter activity within the plasma membrane are largely unknown. In the present study, we used two approaches to examine the effect of changing plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 ) levels on the activities of two electrogenic Na-Pi cotransporters, NaPi-IIa and NaPi-IIb. To deplete plasma membrane PI(4,5)P2 in Xenopus oocytes, we utilized Ciona intestinalis voltage-sensing phosphatase (Ci-VSP), which dephosphorylates PI(4,5)P2 to phosphatidylinositol 4-phosphate (PI(4)P). Upon activation of Ci-VSP, NaPi-IIb currents were significantly decreased, whereas NaPi-IIa currents were unaffected. We also used the rapamycin-inducible Pseudojanin (PJ) system to deplete both PI(4,5)P2 and PI(4)P from the plasma membrane of cultured Neuro 2a cells. Depletion of PI(4,5)P2 and PI(4)P using PJ significantly reduced NaPi-IIb activity, but NaPi-IIa activity was unaffected, which excluded the possibility that NaPi-IIa is equally sensitive to PI(4,5)P2 and PI(4)P. These results indicate that NaPi-IIb activity is regulated by PI(4,5)P2 , whereas NaPi-IIa is not sensitive to either PI(4,5)P2 or PI(4)P. In addition, patch clamp recording of NaPi-IIa and NaPi-IIb currents in cultured mammalian cells enabled kinetic analysis with higher temporal resolution, revealing their distinct kinetic properties.
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Affiliation(s)
- Natsuki Mizutani
- Laboratory of Integrative PhysiologyDepartment of PhysiologyGraduate School of MedicineOsaka UniversitySuitaOsakaJapan
| | - Yoshifumi Okochi
- Laboratory of Integrative PhysiologyDepartment of PhysiologyGraduate School of MedicineOsaka UniversitySuitaOsakaJapan
| | - Yasushi Okamura
- Laboratory of Integrative PhysiologyDepartment of PhysiologyGraduate School of MedicineOsaka UniversitySuitaOsakaJapan
- Graduate School of Frontier BiosciencesOsaka UniversitySuitaOsakaJapan
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Zeng X, Uyar A, Sui D, Donyapour N, Wu D, Dickson A, Hu J. Structural insights into lethal contractural syndrome type 3 (LCCS3) caused by a missense mutation of PIP5Kγ. Biochem J 2018; 475:2257-69. [PMID: 29959184 DOI: 10.1042/BCJ20180326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Signaling molecule phosphatidylinositol 4,5-bisphosphate is produced primarily by phosphatidylinositol 4-phosphate 5-kinase (PIP5K). PIP5K is essential for the development of the human neuronal system, which has been exemplified by a recessive genetic disorder, lethal congenital contractural syndrome type 3, caused by a single aspartate-to-asparagine mutation in the kinase domain of PIP5Kγ. So far, the exact role of this aspartate residue has yet to be elucidated. In this work, we conducted structural, functional and computational studies on a zebrafish PIP5Kα variant with a mutation at the same site. Compared with the structure of the wild-type (WT) protein in the ATP-bound state, the ATP-associating glycine-rich loop of the mutant protein was severely disordered and the temperature factor of ATP was significantly higher. Both observations suggest a greater degree of disorder of the bound ATP, whereas neither the structure of the catalytic site nor the Km toward ATP was substantially affected by the mutation. Microsecond molecular dynamics simulation revealed that negative charge elimination caused by the mutation destabilized the involved hydrogen bonds and affected key electrostatic interactions in the close proximity of ATP. Taken together, our data indicated that the disease-related aspartate residue is a key node in the interaction network crucial for effective ATP binding. This work provides a paradigm of how a subtle but critical structural perturbation caused by a single mutation at the ATP-binding site abolishes the kinase activity, emphasizing that stabilizing substrate in a productive conformational state is crucial for catalysis.
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Abstract
Numerous cellular proteins interact with membrane surfaces to affect essential cellular processes. These interactions can be directed towards a specific lipid component within a membrane, as in the case of phosphoinositides (PIPs), to ensure specific subcellular localization and/or activation. PIPs and cellular PIP-binding domains have been studied extensively to better understand their role in cellular physiology. We applied a pH modulation assay on supported lipid bilayers (SLBs) as a tool to study protein-PIP interactions. In these studies, pH sensitive ortho-Sulforhodamine B conjugated phosphatidylethanolamine is used to detect protein-PIP interactions. Upon binding of a protein to a PIP-containing membrane surface, the interfacial potential is modulated (i.e. change in local pH), shifting the protonation state of the probe. A case study of the successful usage of the pH modulation assay is presented by using phospholipase C delta1 Pleckstrin Homology (PLC-δ1 PH) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) interaction as an example. The apparent dissociation constant (Kd,app) for this interaction was 0.39 ± 0.05 µM, similar to Kd,app values obtained by others. As previously observed, the PLC-δ1 PH domain is PI(4,5)P2 specific, shows weaker binding towards phosphatidylinositol 4-phosphate, and no binding to pure phosphatidylcholine SLBs. The PIP-on-a-chip assay is advantageous over traditional PIP-binding assays, including but not limited to low sample volume and no ligand/receptor labeling requirements, the ability to test high- and low-affinity membrane interactions with both small and large molecules, and improved signal to noise ratio. Accordingly, the usage of the PIP-on-a-chip approach will facilitate the elucidation of mechanisms of a wide range of membrane interactions. Furthermore, this method could potentially be used in identifying therapeutics that modulate protein's capacity to interact with membranes.
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Affiliation(s)
- Djoshkun Shengjuler
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University;
| | - Simou Sun
- Department of Chemistry, The Pennsylvania State University
| | - Paul S Cremer
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University; Department of Chemistry, The Pennsylvania State University;
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University;
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Yadav S, Cockcroft S, Raghu P. The Drosophila photoreceptor as a model system for studying signalling at membrane contact sites. Biochem Soc Trans 2016; 44:447-51. [PMID: 27068953 DOI: 10.1042/BST20150256] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Indexed: 01/08/2023]
Abstract
Several recent studies have demonstrated the existence of membrane contact sites (MCS) between intracellular organelles in eukaryotic cells. Recent exciting studies have also demonstrated the existence of biomolecular interactions at these contact sites in mediating changes in the membrane composition of the cellular compartments. However, the role of such contact sites in regulating organelle function and physiological processes remains less clear. In this review we discuss the existence of a contact site between the plasma membrane (PM) and the endoplasmic reticulum (ER) inDrosophilaphotoreceptors. Further, we discuss the role of specific proteins present at this location in regulating phospholipid turnover and its impact in regulating a physiological process, namely phototransduction.
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Abstract
Transient Receptor Potential (TRP) channels were discovered while analyzing visual mutants in Drosophila. The protein encoded by the transient receptor potential (trp) gene is a Ca(2+) permeable cation channel activated downstream of the phospholipase C (PLC) pathway. While searching for homologs in other organisms, a surprisingly large number of mammalian TRP channels was cloned. The regulation of TRP channels is quite diverse, but many of them are either activated downstream of PLC, or modulated by it. This review will summarize the current knowledge on regulation of TRP channels by PLC, with special focus on TRPC-s, which can be considered as effectors of PLC and the heat- and capsaicin-sensitive TRPV1, which is modulated by the PLC pathway in a complex manner.
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Affiliation(s)
- Tibor Rohacs
- Rutgers, New Jersey Medical School, Newark, NJ, USA.
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