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Moon S, Kim YJ, Park HE, Kim J, Gho YS, Hong WJ, Kim EJ, Lee SK, Suh BC, An G, Jung KH. OsSNDP3 Functions for the Polar Tip Growth in Rice Pollen Together with OsSNDP2, a Paralog of OsSNDP3. RICE (NEW YORK, N.Y.) 2022; 15:39. [PMID: 35859217 PMCID: PMC9300783 DOI: 10.1186/s12284-022-00586-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/09/2022] [Indexed: 06/02/2023]
Abstract
Understanding pollen tube growth is critical for crop yield maintenance. The pollen tube provides a path for sperm cells for fertilization with egg cells. Cells must be subdivided into functionally and structurally distinct compartments for polar tip growth, and phosphoinositides are thought to be one of the facilitators for polarization during pollen tube growth. OsSNDP3 encodes Sec14-nodulin domain-containing protein and localizes in the nucleus and the microdomains of the plasma membrane in tobacco leaf epidermis cells. OsSNDP3 is thought to bind with phosphatidylinositol 4,5-bisphosphate based on the data including the information of basic amino acids in the C-terminal and colocalization with 2X Pleckstrin homology domain of Phospholipase C delta-1. OsSNDP3 interacts with a protein that contains a class I nodulin domain. We discovered that OsSNDP3 plays a significant role in pollen tube germination using CRISPR/Cas9 systems, whereas another pollen-preferential Sec14-nodulin domain-containing protein, OsSNDP2, additively functions with OsSNDP3 during pollen tube germination. Gene Ontology analysis using downregulated genes in ossndp3 indicated that the expression of genes involved in the phosphatidylinositol metabolic process and tip growth was significantly altered in ossndp3. OsSNDP3 aids pollen polar tip growth by binding with phosphatidylinositol 4,5-bisphosphate. We can better understand the roles of phosphoinositides during pollen tube growth by studying the functions of OsSNDP3 and OsSNDP2. And downregulated genes in ossndp3 might be useful targets for future research on polar tip growth.
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Affiliation(s)
- Sunok Moon
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Yu-Jin Kim
- Department of Life Science and Environmental Biochemistry, and Life and Industry Convergence Research Institute, Pusan National University, Miryang-si, 50463, Korea
| | - Ha Eun Park
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Junhyup Kim
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Yun Shil Gho
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Woo-Jong Hong
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Eui-Jung Kim
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Su Kyoung Lee
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | | | - Gynheung An
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea
| | - Ki-Hong Jung
- Department of Genetic Engineering and Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Korea.
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2
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Kim E, Poudyal RS, Lee K, Yu H, Gi E, Kim HU. Chloroplast-localized PITP7 is essential for plant growth and photosynthetic function in Arabidopsis. PHYSIOLOGIA PLANTARUM 2022; 174:e13760. [PMID: 36004734 PMCID: PMC9546280 DOI: 10.1111/ppl.13760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 07/21/2022] [Accepted: 08/02/2022] [Indexed: 06/02/2023]
Abstract
Recent studies of chloroplast-localized Sec14-like protein (CPSFL1, also known as phosphatidylinositol transfer protein 7, PITP7) showed that CPSFL1 is necessary for photoautotropic growth and chloroplast vesicle formation in Arabidopsis (Arabidopsis thaliana). Here, we investigated the functional roles of CPSFL1/PITP7 using two A. thaliana mutants carrying a putative null allele (pitp7-1) and a weak allele (pitp7-2), respectively. PITP7 transcripts were undetectable in pitp7-1 and less abundant in pitp7-2 than in the wild-type (WT). The severity of mutant phenotypes, such as plant developmental abnormalities, levels of plastoquinone-9 (PQ-9) and chlorophylls, photosynthetic protein complexes, and photosynthetic performance, were well related to PITP7 transcript levels. The pitp7-1 mutation was seedling lethal and was associated with significantly lower levels of PQ-9 and major photosynthetic proteins. pitp7-2 plants showed greater susceptibility to high-intensity light stress than the WT, attributable to defects in nonphotochemical quenching and photosynthetic electron transport. PITP7 is specifically bound to phosphatidylinositol phosphates (PIPs) in lipid-binding assays in vitro, and the point mutations R82, H125, E162, or K233 reduced the binding affinity of PITP7 to PIPs. Further, constitutive expression of PITP7H125Q or PITP7E162K in pitp7-1 homozygous plants restored autotrophic growth in soil but without fully complementing the mutant phenotypes. Consistent with a previous study, our results demonstrate that PITP7 is essential for plant development, particularly the accumulation of PQ-9 and photosynthetic complexes. We propose a possible role for PITP7 in membrane trafficking of hydrophobic ligands such as PQ-9 and carotenoids through chloroplast vesicle formation or direct binding involving PIPs.
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Affiliation(s)
- Eun‐Ha Kim
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Roshan Sharma Poudyal
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Kyeong‐Ryeol Lee
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Hami Yu
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Eunji Gi
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Hyun Uk Kim
- Department of Bioindustry and Bioresource EngineeringPlant Engineering Research Institute, Sejong UniversitySeoulRepublic of Korea
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3
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Khan D, Lee D, Gulten G, Aggarwal A, Wofford J, Krieger I, Tripathi A, Patrick JW, Eckert DM, Laganowsky A, Sacchettini J, Lindahl P, Bankaitis VA. A Sec14-like phosphatidylinositol transfer protein paralog defines a novel class of heme-binding proteins. eLife 2020; 9:57081. [PMID: 32780017 PMCID: PMC7462610 DOI: 10.7554/elife.57081] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/10/2020] [Indexed: 01/02/2023] Open
Abstract
Yeast Sfh5 is an unusual member of the Sec14-like phosphatidylinositol transfer protein (PITP) family. Whereas PITPs are defined by their abilities to transfer phosphatidylinositol between membranes in vitro, and to stimulate phosphoinositide signaling in vivo, Sfh5 does not exhibit these activities. Rather, Sfh5 is a redox-active penta-coordinate high spin FeIII hemoprotein with an unusual heme-binding arrangement that involves a co-axial tyrosine/histidine coordination strategy and a complex electronic structure connecting the open shell iron d-orbitals with three aromatic ring systems. That Sfh5 is not a PITP is supported by demonstrations that heme is not a readily exchangeable ligand, and that phosphatidylinositol-exchange activity is resuscitated in heme binding-deficient Sfh5 mutants. The collective data identify Sfh5 as the prototype of a new class of fungal hemoproteins, and emphasize the versatility of the Sec14-fold as scaffold for translating the binding of chemically distinct ligands to the control of diverse sets of cellular activities.
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Affiliation(s)
- Danish Khan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Dongju Lee
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States
| | - Gulcin Gulten
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Anup Aggarwal
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Joshua Wofford
- Department of Chemistry, Texas A&M University, College Station, United States.,Department of Chemistry, Charleston Southern University, North Charleston, United States
| | - Inna Krieger
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States
| | - John W Patrick
- Department of Chemistry, Texas A&M University, College Station, United States
| | - Debra M Eckert
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Arthur Laganowsky
- Department of Chemistry, Texas A&M University, College Station, United States
| | - James Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States
| | - Paul Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States.,Department of Chemistry, Texas A&M University, College Station, United States
| | - Vytas A Bankaitis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, United States.,Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, United States.,Department of Chemistry, Texas A&M University, College Station, United States
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4
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Hertle AP, García-Cerdán JG, Armbruster U, Shih R, Lee JJ, Wong W, Niyogi KK. A Sec14 domain protein is required for photoautotrophic growth and chloroplast vesicle formation in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2020; 117:9101-9111. [PMID: 32245810 PMCID: PMC7183190 DOI: 10.1073/pnas.1916946117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In eukaryotic photosynthetic organisms, the conversion of solar into chemical energy occurs in thylakoid membranes in the chloroplast. How thylakoid membranes are formed and maintained is poorly understood. However, previous observations of vesicles adjacent to the stromal side of the inner envelope membrane of the chloroplast suggest a possible role of membrane transport via vesicle trafficking from the inner envelope to the thylakoids. Here we show that the model plant Arabidopsis thaliana has a chloroplast-localized Sec14-like protein (CPSFL1) that is necessary for photoautotrophic growth and vesicle formation at the inner envelope membrane of the chloroplast. The cpsfl1 mutants are seedling lethal, show a defect in thylakoid structure, and lack chloroplast vesicles. Sec14 domain proteins are found only in eukaryotes and have been well characterized in yeast, where they regulate vesicle budding at the trans-Golgi network. Like the yeast Sec14p, CPSFL1 binds phosphatidylinositol phosphates (PIPs) and phosphatidic acid (PA) and acts as a phosphatidylinositol transfer protein in vitro, and expression of Arabidopsis CPSFL1 can complement the yeast sec14 mutation. CPSFL1 can transfer PIP into PA-rich membrane bilayers in vitro, suggesting that CPSFL1 potentially facilitates vesicle formation by trafficking PA and/or PIP, known regulators of membrane trafficking between organellar subcompartments. These results underscore the role of vesicles in thylakoid biogenesis and/or maintenance. CPSFL1 appears to be an example of a eukaryotic cytosolic protein that has been coopted for a function in the chloroplast, an organelle derived from endosymbiosis of a cyanobacterium.
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Affiliation(s)
- Alexander P Hertle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
| | - José G García-Cerdán
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Ute Armbruster
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
| | - Robert Shih
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Jimmy J Lee
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
| | - Winnie Wong
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
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5
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Hua-Ying M, Wen-Ju W, Wei-Hua S, Ya-Chun S, Feng L, Cong-Na L, Ling W, Xu Z, Li-Ping X, You-Xiong Q. Genome-wide identification, phylogeny, and expression analysis of Sec14-like PITP gene family in sugarcane. PLANT CELL REPORTS 2019; 38:637-655. [PMID: 30747272 DOI: 10.1007/s00299-019-02394-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 02/02/2019] [Indexed: 06/09/2023]
Abstract
Six Sec14-like PITP genes from sugarcane were identified, two of them were cloned, and their biological functions were characterized indicating their involvement in plant defense against biotic and abiotic stresses. Sec14, a phosphatidylinositol transfer protein (PITP) is widely present in eukaryotes. In this study, the structure and expression patterns of six Sec14-like PITP genes (ScSEC14-1, ScSEC14p, ScSFH1, ScSFH2, ScPATL1, and ScPATL2) from sugarcane were analyzed, and two of them (ScSEC14-1 and ScSEC14p) were cloned and functionally verified. Phylogenetic analysis divided these genes into four groups, including group I (ScSFH1 and ScSFH2), group II (ScPATL1 and ScPATL2), Group III (ScSEC14p), and group V (ScSEC14-1). qRT-PCR analysis showed tissue-specific expression of these genes, primarily in the root, leaf, and bud tissues. They responded differently to SA, MeJA, and ABA stresses. ScSEC14-1, ScSEC14p, and ScSFH2 were upregulated by CuCl2 and CdCl2, while ScSEC14-1, ScSFH1, ScSFH2, and ScPATL1 were upregulated by PEG and NaCl. When infected by Sporisorium scitamineum, the transcripts of ScSFH1, ScSFH2, ScPATL1, and ScPATL2 were upregulated in the resistant genotype Yacheng 05-179, while those of ScSEC14-1 and ScSEC14p were upregulated in the susceptible genotype ROC22. Subcellular localization showed that ScSEC14-1 and ScSEC14p were mainly localized in the plasma membrane and cytoplasm. Enhanced growth of Escherichia coli BL21 cells expressing ScSEC14-1 and ScSEC14p showed high tolerance to NaCl and mannitol stresses. The transient overexpression of ScSEC14-1 and ScSEC14p in Nicotiana benthamiana leaves enhanced its resistance to the infection of tobacco pathogens Ralstonia solanacearum and Fusarium solani var. coeruleum. We can conclude the involvement of ScSEC14-1 and ScSEC14p in the defense against biotic and abiotic stresses, which should facilitate further research on Sec14-like PITP gene family, especially its regulatory mechanisms in sugarcane.
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Affiliation(s)
- Mao Hua-Ying
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wang Wen-Ju
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Su Wei-Hua
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Su Ya-Chun
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Liu Feng
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Li Cong-Na
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Wang Ling
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Zhang Xu
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xu Li-Ping
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Que You-Xiong
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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6
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Tejos R, Rodriguez-Furlán C, Adamowski M, Sauer M, Norambuena L, Friml J. PATELLINS are regulators of auxin-mediated PIN1 relocation and plant development in Arabidopsis thaliana. J Cell Sci 2018; 131:jcs.204198. [PMID: 28687624 DOI: 10.1242/jcs.204198] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/05/2017] [Indexed: 01/02/2023] Open
Abstract
Coordinated cell polarization in developing tissues is a recurrent theme in multicellular organisms. In plants, a directional distribution of the plant hormone auxin is at the core of many developmental programs. A feedback regulation of auxin on the polarized localization of PIN auxin transporters in individual cells has been proposed as a self-organizing mechanism for coordinated tissue polarization, but the molecular mechanisms linking auxin signalling to PIN-dependent auxin transport remain unknown. We used a microarray-based approach to find regulators of the auxin-induced PIN relocation in Arabidopsis thaliana root, and identified a subset of a family of phosphatidylinositol transfer proteins (PITPs), the PATELLINs (PATLs). Here, we show that PATLs are expressed in partially overlapping cell types in different tissues going through mitosis or initiating differentiation programs. PATLs are plasma membrane-associated proteins accumulated in Arabidopsis embryos, primary roots, lateral root primordia and developing stomata. Higher order patl mutants display reduced PIN1 repolarization in response to auxin, shorter root apical meristem, and drastic defects in embryo and seedling development. This suggests that PATLs play a redundant and crucial role in polarity and patterning in Arabidopsis.
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Affiliation(s)
- Ricardo Tejos
- Facultad de Recursos Naturales Renovables, Universidad Arturo Prat, 111093 Iquique, Chile
| | - Cecilia Rodriguez-Furlán
- Plant Molecular Biology Centre, Biology Department, Faculty of Sciences, Universidad de Chile, 7800024 Santiago, Chile
| | - Maciej Adamowski
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria
| | - Michael Sauer
- Department of Plant Physiology, University of Potsdam, D-14476 Potsdam, Germany
| | - Lorena Norambuena
- Plant Molecular Biology Centre, Biology Department, Faculty of Sciences, Universidad de Chile, 7800024 Santiago, Chile
| | - Jiří Friml
- Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria
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7
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Huang J, Ghosh R, Tripathi A, Lönnfors M, Somerharju P, Bankaitis VA. Two-ligand priming mechanism for potentiated phosphoinositide synthesis is an evolutionarily conserved feature of Sec14-like phosphatidylinositol and phosphatidylcholine exchange proteins. Mol Biol Cell 2016; 27:2317-30. [PMID: 27193303 PMCID: PMC4945147 DOI: 10.1091/mbc.e16-04-0221] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/12/2016] [Indexed: 12/21/2022] Open
Abstract
The two-ligand priming mechanism for stimulated phosphoinositide synthesis described for Saccharomyces Sec14 is also a conserved feature of Sec14-like phosphatidylinositol- and phosphatidylcholine-transfer proteins of the most evolutionarily advanced plants. Lipid signaling, particularly phosphoinositide signaling, plays a key role in regulating the extreme polarized membrane growth that drives root hair development in plants. The Arabidopsis AtSFH1 gene encodes a two-domain protein with an amino-terminal Sec14-like phosphatidylinositol transfer protein (PITP) domain linked to a carboxy-terminal nodulin domain. AtSfh1 is critical for promoting the spatially highly organized phosphatidylinositol-4,5-bisphosphate signaling program required for establishment and maintenance of polarized root hair growth. Here we demonstrate that, like the yeast Sec14, the AtSfh1 PITP domain requires both its phosphatidylinositol (PtdIns)- and phosphatidylcholine (PtdCho)-binding properties to stimulate PtdIns-4-phosphate [PtdIns(4)P] synthesis. Moreover, we show that both phospholipid-binding activities are essential for AtSfh1 activity in supporting polarized root hair growth. Finally, we report genetic and biochemical evidence that the two-ligand mechanism for potentiation of PtdIns 4-OH kinase activity is a broadly conserved feature of plant Sec14-nodulin proteins, and that this strategy appeared only late in plant evolution. Taken together, the data indicate that the PtdIns/PtdCho-exchange mechanism for stimulated PtdIns(4)P synthesis either arose independently during evolution in yeast and in higher plants, or a suitable genetic module was introduced to higher plants from a fungal source and subsequently exploited by them.
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Affiliation(s)
- Jin Huang
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
| | - Ratna Ghosh
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
| | - Max Lönnfors
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114
| | - Pentti Somerharju
- Faculty of Medicine, Department of Biochemistry and Developmental Biology, University of Helsinki, 00290 Helsinki, Finland
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128 Department of Chemistry, Texas A&M University, College Station, TX 77840
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8
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Kiełbowicz-Matuk A, Banachowicz E, Turska-Tarska A, Rey P, Rorat T. Expression and characterization of a barley phosphatidylinositol transfer protein structurally homologous to the yeast Sec14p protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 246:98-111. [PMID: 26993240 DOI: 10.1016/j.plantsci.2016.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/16/2016] [Accepted: 02/20/2016] [Indexed: 06/05/2023]
Abstract
Phosphatidylinositol transfer proteins (PITPs) include a large group of proteins implicated in the non-vesicular traffic of phosphatidylinositol (PI) between membranes. In yeast, the structure and function of the PITP Sec14-p protein have been well characterized. In contrast, the knowledge on plant PITP proteins is very scarce. In this work, we characterized a novel type of PITP protein in barley named HvSec14p and related to the yeast Sec14-p protein. Our data reveal that HvSec14p consists of only the Sec14p-domain structurally homologous to the yeast phosphoinositide binding domain. We show that HvSec14p expression is up-regulated at both transcript and protein levels at specific stages of development during seed formation and germination, and in leaves of a drought-tolerant barley genotype under osmotic constraints. Modeling analyses of the protein three-dimensional structure revealed its capacity to dock the phosphoinositides, PtdIns(3)P, PtdIns(4)P, PtdIns(5)P and PtdIns(3,5)P2. Consistently, the recombinant HvSec14p protein is able to bind in vitro most PIP types, the highest affinity being observed with PtdIns(3,5)P2. Based on the high gene expression at specific developmental stages and in drought-tolerant barley genotypes, we propose that HvSec14p plays essential roles in the biogenesis of membranes in expanding cells and in their preservation under osmotic stress conditions.
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Affiliation(s)
| | - Ewa Banachowicz
- Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland.
| | - Anna Turska-Tarska
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland.
| | - Pascal Rey
- CEA, DSV, IBEB, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance, F-13108, France; CNRS, UMR 7265 Biologie Végétale & Microbiologie Environnementale, Saint-Paul-lez-Durance, F-13108, France; Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France.
| | - Tadeusz Rorat
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland.
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9
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Huang J, Ghosh R, Bankaitis VA. Sec14-like phosphatidylinositol transfer proteins and the biological landscape of phosphoinositide signaling in plants. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1352-1364. [PMID: 27038688 DOI: 10.1016/j.bbalip.2016.03.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 01/01/2023]
Abstract
Phosphoinositides and soluble inositol phosphates are essential components of a complex intracellular chemical code that regulates major aspects of lipid signaling in eukaryotes. These involvements span a broad array of biological outcomes and activities, and cells are faced with the problem of how to compartmentalize and organize these various signaling events into a coherent scheme. It is in the arena of how phosphoinositide signaling circuits are integrated and, and how phosphoinositide pools are functionally defined and channeled to privileged effectors, that phosphatidylinositol (PtdIns) transfer proteins (PITPs) are emerging as critical players. As plant systems offer some unique advantages and opportunities for study of these proteins, we discuss herein our perspectives regarding the progress made in plant systems regarding PITP function. We also suggest interesting prospects that plant systems hold for interrogating how PITPs work, particularly in multi-domain contexts, to diversify the biological outcomes for phosphoinositide signaling. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner.
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Affiliation(s)
- Jin Huang
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA.
| | - Ratna Ghosh
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA
| | - Vytas A Bankaitis
- Department of Molecular & Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX 77843-1114 USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-1114 USA; Department of Chemistry, Texas A&M University, College Station, TX 77843-1114 USA.
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10
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Ciesielska K, Li B, Groeneboer S, Van Bogaert I, Lin YC, Soetaert W, Van de Peer Y, Devreese B. SILAC-Based Proteome Analysis of Starmerella bombicola Sophorolipid Production. J Proteome Res 2013; 12:4376-92. [DOI: 10.1021/pr400392a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Katarzyna Ciesielska
- Laboratory
for Protein Biochemistry and Biomolecular Engineering, Department
of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat
35, 9000 Ghent, Belgium
| | - Bing Li
- VIB
Department of Plant Systems Biology and Department of Plant Biotechnology
and Bioinformatics, Ghent University, Technologiepark 927 B-9052, 9000 Ghent, Belgium
| | - Sara Groeneboer
- Laboratory
for Protein Biochemistry and Biomolecular Engineering, Department
of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat
35, 9000 Ghent, Belgium
| | - Inge Van Bogaert
- Laboratory
of Industrial Biotechnology and Biocatalysis, Ghent University, Coupure
Links 653, 9000 Ghent, Belgium
| | | | - Wim Soetaert
- Laboratory
of Industrial Biotechnology and Biocatalysis, Ghent University, Coupure
Links 653, 9000 Ghent, Belgium
| | - Yves Van de Peer
- VIB
Department of Plant Systems Biology and Department of Plant Biotechnology
and Bioinformatics, Ghent University, Technologiepark 927 B-9052, 9000 Ghent, Belgium
| | - Bart Devreese
- Laboratory
for Protein Biochemistry and Biomolecular Engineering, Department
of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat
35, 9000 Ghent, Belgium
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11
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Heilmann M, Heilmann I. Arranged marriage in lipid signalling? The limited choices of PtdIns(4,5)P2 in finding the right partner. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:789-797. [PMID: 23627419 DOI: 10.1111/plb.12025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/07/2013] [Indexed: 06/02/2023]
Abstract
Inositol-containing phospholipids (phosphoinositides, PIs) control numerous cellular processes in eukaryotic cells. For plants, a key involvement of PIs has been demonstrated in the regulation of membrane trafficking, cytoskeletal dynamics and in processes mediating the adaptation to changing environmental conditions. Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) mediates its cellular functions via binding to various alternative target proteins. Such downstream targets of PtdIns(4,5)P(2) are characterised by the possession of specific lipid-binding domains, and binding of the PtdIns(4,5)P(2) ligand exerts effects on their activity or localisation. The large number of potential alternative binding partners - and associated cellular processes - raises the question how alternative or even contrapuntal effects of PtdIns(4,5)P(2) are orchestrated to enable cellular function. This article aims to provide an overview of recent insights and new views on how distinct functional pools of PtdIns(4,5)P(2) are generated and maintained. The emerging picture suggests that PtdIns(4,5)P(2) species containing different fatty acids influence the lateral mobility of the lipids in the membrane, possibly enabling specific interactions of PtdIns(4,5)P(2) pools with certain downstream targets. PtdIns(4,5)P(2) pools with certain functions might also be defined by protein-protein interactions of PI4P 5-kinases, which pass PtdIns(4,5)P(2) only to certain downstream partners. Individually or in combination, PtdIns(4,5)P(2) species and specific protein-protein interactions of PI4P 5-kinases might contribute to the channelling of PtdIns(4,5)P(2) signals towards specific functional effects. The dynamic nature of PI-dependent signalling complexes with specific functions is an added challenge for future studies of plant PI signalling.
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Affiliation(s)
- M Heilmann
- Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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12
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Kulik A, Wawer I, Krzywińska E, Bucholc M, Dobrowolska G. SnRK2 protein kinases--key regulators of plant response to abiotic stresses. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2011; 15:859-72. [PMID: 22136638 DOI: 10.1089/omi.2011.0091] [Citation(s) in RCA: 256] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The SnRK2 family members are plant-specific serine/threonine kinases involved in plant response to abiotic stresses and abscisic acid (ABA)-dependent plant development. SnRK2s have been classed into three groups; group 1 comprises kinases not activated by ABA, group 2 comprises kinases not activated or activated very weakly by ABA, and group 3 comprises kinases strongly activated by ABA. So far, the ABA-dependent kinases belonging to group 3 have been studied most thoroughly. They are considered major regulators of plant response to ABA. The regulation of the plant response to ABA via SnRK2s pathways occurs by direct phosphorylation of various downstream targets, for example, SLAC1, KAT1, AtRbohF, and transcription factors required for the expression of numerous stress response genes. Members of group 2 share some cellular functions with group 3 kinases; however, their contribution to ABA-related responses is not clear. There are strong indications that they are positive regulators of plant responses to water deficit. Most probably they complement the ABA-dependent kinases in plant defense against environmental stress. So far, data concerning the physiological role of ABA-independent SnRK2s are very limited; it is to be expected they will be studied extensively in the nearest future.
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Affiliation(s)
- Anna Kulik
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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13
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Ghosh R, Bankaitis VA. Phosphatidylinositol transfer proteins: negotiating the regulatory interface between lipid metabolism and lipid signaling in diverse cellular processes. Biofactors 2011; 37:290-308. [PMID: 21915936 DOI: 10.1002/biof.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphoinositides represent only a small percentage of the total cellular lipid pool. Yet, these molecules play crucial roles in diverse intracellular processes such as signal transduction at membrane-cytosol interface, regulation of membrane trafficking, cytoskeleton organization, nuclear events, and the permeability and transport functions of the membrane. A central principle in such lipid-mediated signaling is the appropriate coordination of these events. Such an intricate coordination demands fine spatial and temporal control of lipid metabolism and organization, and consistent mechanisms for specifically coupling these parameters to dedicated physiological processes. In that regard, recent studies have identified Sec14-like phosphatidylcholine transfer protein (PITPs) as "coincidence detectors," which spatially and temporally link the diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. The integral role of PITPs in eukaryotic signal transduction design is amply demonstrated by the mammalian diseases associated with the derangements in the function of these proteins, to stress response and developmental regulation in plants, to fungal dimorphism and pathogenicity, to membrane trafficking in yeast, and higher eukaryotes. This review updates the recent advances made in the understanding of how these proteins, specifically PITPs of the Sec14-protein superfamily, operate at the molecular level and further describes how this knowledge has advanced our perception on the diverse biological functions of PITPs.
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Affiliation(s)
- Ratna Ghosh
- Lineberger Comprehensive Cancer Center, Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27526-7090, USA.
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14
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Schaaf G, Dynowski M, Mousley CJ, Shah SD, Yuan P, Winklbauer EM, de Campos MKF, Trettin K, Quinones MC, Smirnova TI, Yanagisawa LL, Ortlund EA, Bankaitis VA. Resurrection of a functional phosphatidylinositol transfer protein from a pseudo-Sec14 scaffold by directed evolution. Mol Biol Cell 2011; 22:892-905. [PMID: 21248202 PMCID: PMC3057712 DOI: 10.1091/mbc.e10-11-0903] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Sec14-superfamily proteins integrate the lipid metabolome with phosphoinositide synthesis and signaling via primed presentation of phosphatidylinositol (PtdIns) to PtdIns kinases. Sec14 action as a PtdIns-presentation scaffold requires heterotypic exchange of phosphatidylcholine (PtdCho) for PtdIns, or vice versa, in a poorly understood progression of regulated conformational transitions. We identify mutations that confer Sec14-like activities to a functionally inert pseudo-Sec14 (Sfh1), which seemingly conserves all of the structural requirements for Sec14 function. Unexpectedly, the "activation" phenotype results from alteration of residues conserved between Sfh1 and Sec14. Using biochemical and biophysical, structural, and computational approaches, we find the activation mechanism reconfigures atomic interactions between amino acid side chains and internal water in an unusual hydrophilic microenvironment within the hydrophobic Sfh1 ligand-binding cavity. These altered dynamics reconstitute a functional "gating module" that propagates conformational energy from within the hydrophobic pocket to the helical unit that gates pocket access. The net effect is enhanced rates of phospholipid-cycling into and out of the Sfh1* hydrophobic pocket. Taken together, the directed evolution approach reveals an unexpectedly flexible functional engineering of a Sec14-like PtdIns transfer protein-an engineering invisible to standard bioinformatic, crystallographic, and rational mutagenesis approaches.
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Affiliation(s)
- Gabriel Schaaf
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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15
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Thole JM, Nielsen E. Phosphoinositides in plants: novel functions in membrane trafficking. CURRENT OPINION IN PLANT BIOLOGY 2008; 11:620-31. [PMID: 19028349 DOI: 10.1016/j.pbi.2008.10.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 09/23/2008] [Accepted: 10/28/2008] [Indexed: 05/07/2023]
Abstract
Tight regulation of membrane trafficking is crucial to the proper maintenance of the endomembrane trafficking system of eukaryotic cells. Distinct organelles must maintain their identities while at the same time continuously accepting, sorting, and exchanging membrane and luminal cargo constituents. Additionally, many of these organelles differentiate specialized subdomains containing distinct sets of lipids and proteins and restrict certain aspects of membrane trafficking to these regions of the organelle. Phosphoinositides (PIs) are a class of membrane lipids that have emerged as key components in some of these membrane trafficking events. The ability of these lipids to be rapidly produced, modified, and hydrolyzed by distinct classes of phosphatidylinositol (PtdIns) kinases, phosphatases, and phospholipases, allows for their use as finely tuned spatial and temporal landmarks for organelle and sub-organelle domains. In this review we will attempt to highlight some of the recent studies of the roles of this class of lipids in plant membrane trafficking, particularly on their important roles in polarized membrane trafficking in plants.
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Affiliation(s)
- Julie M Thole
- Department of Biology, Washington University, One Brookings Drive, St. Louis, MO 63130, United States
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16
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Phillips SE, Vincent P, Rizzieri KE, Schaaf G, Bankaitis VA, Gaucher EA. The Diverse Biological Functions of Phosphatidylinositol Transfer Proteins in Eukaryotes. Crit Rev Biochem Mol Biol 2008; 41:21-49. [PMID: 16455519 DOI: 10.1080/10409230500519573] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Phosphatidylinositol/phosphatidylcholine transfer proteins (PITPs) remain largely functionally uncharacterized, despite the fact that they are highly conserved and are found in all eukaryotic cells thus far examined by biochemical or sequence analysis approaches. The available data indicate a role for PITPs in regulating specific interfaces between lipid-signaling and cellular function. In this regard, a role for PITPs in controlling specific membrane trafficking events is emerging as a common functional theme. However, the mechanisms by which PITPs regulate lipid-signaling and membrane-trafficking functions remain unresolved. Specific PITP dysfunctions are now linked to neurodegenerative and intestinal malabsorption diseases in mammals, to stress response and developmental regulation in higher plants, and to previously uncharacterized pathways for regulating membrane trafficking in yeast and higher eukaryotes, making it clear that PITPs are integral parts of a highly conserved signal transduction strategy in eukaryotes. Herein, we review recent progress in deciphering the biological functions of PITPs, and discuss some of the open questions that remain.
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Affiliation(s)
- Scott E Phillips
- Department of Cell and Developmental Biology, School of Medicine, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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17
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Alternative metabolic fates of phosphatidylinositol produced by phosphatidylinositol synthase isoforms in Arabidopsis thaliana. Biochem J 2008; 413:115-24. [PMID: 18402553 DOI: 10.1042/bj20071371] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PtdIns is an important precursor for inositol-containing lipids, including polyphosphoinositides, which have multiple essential functions in eukaryotic cells. It was previously proposed that different regulatory functions of inositol-containing lipids may be performed by independent lipid pools; however, it remains unclear how such subcellular pools are established and maintained. In the present paper, a previously uncharacterized Arabidopsis gene product with similarity to the known Arabidopsis PIS (PtdIns synthase), PIS1, is shown to be an active enzyme, PIS2, capable of producing PtdIns in vitro. PIS1 and PIS2 diverged slightly in substrate preferences for CDP-DAG [cytidinediphospho-DAG (diacylglycerol)] species differing in fatty acid composition, PIS2 preferring unsaturated substrates in vitro. Transient expression of fluorescently tagged PIS1 or PIS2 in onion epidermal cells indicates localization of both enzymes in the ER (endoplasmic reticulum) and, possibly, Golgi, as was reported previously for fungal and mammalian homologues. Constitutive ectopic overexpression of PIS1 or PIS2 in Arabidopsis plants resulted in elevated levels of PtdIns in leaves. PIS2-overexpressors additionally exhibited significantly elevated levels of PtdIns(4)P and PtdIns(4,5)P(2), whereas polyphosphoinositides were not elevated in plants overexpressing PIS1. In contrast, PIS1-overexpressors contained significantly elevated levels of DAG and PtdEtn (phosphatidylethanolamine), an effect not observed in plants overexpressing PIS2. Biochemical analysis of transgenic plants with regards to fatty acids associated with relevant lipids indicates that lipids increasing with PIS1 overexpression were enriched in saturated or monounsaturated fatty acids, whereas lipids increasing with PIS2 overexpression, including polyphosphoinositides, contained more unsaturated fatty acids. The results indicate that PtdIns populations originating from different PIS isoforms may enter alternative routes of metabolic conversion, possibly based on specificity and immediate metabolic context of the biosynthetic enzymes.
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18
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Mousley CJ, Tyeryar KR, Vincent-Pope P, Bankaitis VA. The Sec14-superfamily and the regulatory interface between phospholipid metabolism and membrane trafficking. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:727-36. [PMID: 17512778 PMCID: PMC2001170 DOI: 10.1016/j.bbalip.2007.04.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 03/26/2007] [Accepted: 04/03/2007] [Indexed: 12/11/2022]
Abstract
A central principle of signal transduction is the appropriate control of the process so that relevant signals can be detected with fine spatial and temporal resolution. In the case of lipid-mediated signaling, organization and metabolism of specific lipid mediators is an important aspect of such control. Herein, we review the emerging evidence regarding the roles of Sec14-like phosphatidylinositol transfer proteins (PITPs) in the action of intracellular signaling networks; particularly as these relate to membrane trafficking. Finally, we explore developing ideas regarding how Sec14-like PITPs execute biological function. As Sec14-like proteins define a protein superfamily with diverse lipid (or lipophile) binding capabilities, it is likely these under-investigated proteins will be ultimately demonstrated as a ubiquitously important set of biological regulators whose functions influence a large territory in the signaling landscape of eukaryotic cells.
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Affiliation(s)
- Carl J Mousley
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA.
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19
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Mo P, Zhu Y, Liu X, Zhang A, Yan C, Wang D. Identification of two phosphatidylinositol/phosphatidylcholine transfer protein genes that are predominately transcribed in the flowers of Arabidopsis thaliana. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:478-86. [PMID: 16697077 DOI: 10.1016/j.jplph.2006.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 03/24/2006] [Indexed: 05/09/2023]
Abstract
The Sec14 protein (Sec14p) and its homologs are involved in the transfer of phosphatidylinositol/phosphatidylcholine phospholipids in eukaryotic cells. In the completely sequenced genome of Arabidopsis thaliana, multiple genes encoding putative Sec14p homologs have been predicted based on bioinformatic analysis. Here we report the identification of two yeast Sec14-like genes (designated as AtSFH3 and AtSFH12, respectively) that are predominately transcribed in Arabidopsis flowers. The deduced amino acid sequences of AtSfh3p and AtSfh12p exhibited high similarity to that of Sec14p. Ectopic expression of AtSfh3p or AtSfh12p corrected the high temperature sensitive phenotype caused by Sec14p functional deficiency in Saccharomyces cerevisiae, indicating that the two plant homologs are functional in the intracellular environment. AtSFH3 transcripts were detected in flowers, stems and immature siliques but not roots and leaves, with a relatively higher transcript level in the flowers. In contrast, AtSFH12 transcripts were only detectable in the flowers. Based on histochemical staining of beta-glucuronidase (GUS) activities in the transgenic Arabidopsis plants harboring promoter::GUS constructs, AtSFH3 transcription was first detected in the stigma papillae of the flowers at stage 11, and then in the pollen grains before and after fertilization. On the other hand, AtSFH12 transcription was only found in the mature and germinating pollen grains. The information from this study may provide useful clue for further analysis of the function of plant Sec14p homologs in the development of the male gametic cells and/or the fertilization process in higher plants.
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Affiliation(s)
- Pingli Mo
- The College of Life Sciences, Xiamen University, Xiamen, China
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20
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Bankaitis VA, Vincent P, Merkulova M, Tyeryar K, Liu Y. Phosphatidylinositol transfer proteins and functional specification of lipid signaling pools. ACTA ACUST UNITED AC 2007; 47:27-40. [PMID: 17335879 PMCID: PMC2080876 DOI: 10.1016/j.advenzreg.2006.12.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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21
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Peterman TK, Sequeira AS, Samia JA, Lunde EE. Molecular cloning and characterization of patellin1, a novel sec14-related protein, from zucchini (Cucurbita pepo). JOURNAL OF PLANT PHYSIOLOGY 2006; 163:1150-8. [PMID: 16542754 DOI: 10.1016/j.jplph.2006.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Accepted: 01/24/2006] [Indexed: 05/07/2023]
Abstract
A full-length patellin1 (PATL1) cDNA was cloned and characterized from zucchini (Cucurbita pepo). PATL1, originally discovered in the higher plant Arabidopsis thaliana, is a plant Sec14-related protein that localizes to the cell plate during the late stages of cytokinesis. PATL1 is related in sequence to other eukaryotic proteins involved in membrane trafficking and is thought to participate in vesicle trafficking events associated with cell plate maturation. The zucchini PATL1 (CpPATL1) cDNA predicts a 605 amino acid protein which consists of an acidic N-terminal domain (pI=4.2) followed by a Sec14 lipid-binding domain and a C-terminal Golgi dynamics domain (GOLD). The predicted CpPATL1 protein sequence shows a high degree of similarity to Arabidopsis PATL1, especially in the Sec14 (84%) and GOLD domains (87%). A phylogenetic analysis of all available full-length PATL sequences revealed that the PATLs belong to four distinct clades; CpPATL1 is a member of the PATL1/2 clade. RT-PCR analysis showed that the CpPATL1 gene is highly expressed throughout the plant. The domain structure, as well as biochemical fractionation studies, which demonstrated that CpPATL1 is a peripheral membrane protein, support a role in membrane trafficking events.
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Affiliation(s)
- T Kaye Peterman
- Department of Biological Sciences, Wellesley College, Wellesley, MA 02481, USA.
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22
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Schaaf G, Betts L, Garrett TA, Raetz CRH, Bankaitis VA. Crystallization and preliminary X-ray diffraction analysis of phospholipid-bound Sfh1p, a member of the Saccharomyces cerevisiae Sec14p-like phosphatidylinositol transfer protein family. Acta Crystallogr Sect F Struct Biol Cryst Commun 2006; 62:1156-60. [PMID: 17077504 PMCID: PMC2225215 DOI: 10.1107/s1744309106041728] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 10/09/2006] [Indexed: 10/24/2022]
Abstract
Sec14p is the major phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer protein in the budding yeast Saccharomyces cerevisiae and is the founding member of a large eukaryotic protein superfamily. This protein catalyzes the exchange of either PtdIns or PtdCho between membrane bilayers in vitro and this exchange reaction requires no external input of energy or of other protein cofactors. Despite the previous elucidation of the crystal structure of a detergent-bound form of Sec14p, the conformational changes that accompany the phospholipid-exchange reaction remain undefined. Moreover, a structural appreciation of how Sec14p or its homologs bind their various phospholipid substrates remains elusive. Here, the purification and crystallization of yeast Sfh1p, the protein most closely related to Sec14p, are reported. A combination of electrospray ionization mass-spectrometry and collision-induced decomposition mass-spectrometry methods indicate that recombinant Sfh1p loads predominantly with phosphatidylethanolamine. Unlike phospholipid-bound forms of Sec14p, this form of Sfh1p crystallizes readily in the absence of detergent. Sfh1p crystals diffract to 2.5 A and belong to the orthorhombic primitive space group P2(1)2(1)2(1), with unit-cell parameters a = 49.40, b = 71.55, c = 98.21 A, alpha = beta = gamma = 90 degrees. One Sfh1p molecule is present in the asymmetric unit (V(M) = 2.5 A(3) Da(-1); V(s) = 50%). Crystallization of a phospholipid-bound Sec14p-like protein is a critical first step in obtaining the first high-resolution picture of how proteins of the Sec14p superfamily bind their phospholipid ligands. This information will significantly extend our current understanding of how Sec14p-like proteins catalyze phospholipid exchange.
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Affiliation(s)
- Gabriel Schaaf
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Laurie Betts
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7365, USA
| | - Teresa A. Garrett
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Vytas A. Bankaitis
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
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23
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Ile KE, Schaaf G, Bankaitis VA. Phosphatidylinositol transfer proteins and cellular nanoreactors for lipid signaling. Nat Chem Biol 2006; 2:576-83. [PMID: 17051233 DOI: 10.1038/nchembio835] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Membrane lipids function as structural molecules, reservoirs for second messengers, membrane platforms that scaffold protein assembly and regulators of enzymes and ion channels. Such diverse lipid functions contribute substantially to cellular mechanisms for fine-tuning membrane-signaling events. Meaningful coordination of these events requires exquisite spatial and temporal control of lipid metabolism and organization, and reliable mechanisms for specifically coupling these parameters to dedicated physiological processes. Recent studies suggest such integration is linked to the action of phosphatidylinositol transfer proteins that operate at the interface of the metabolism, trafficking and organization of specific lipids.
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Affiliation(s)
- Kristina E Ile
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7090, USA
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24
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Phillips SE, Ile KE, Boukhelifa M, Huijbregts RP, Bankaitis VA. Specific and nonspecific membrane-binding determinants cooperate in targeting phosphatidylinositol transfer protein beta-isoform to the mammalian trans-Golgi network. Mol Biol Cell 2006; 17:2498-512. [PMID: 16540520 PMCID: PMC1474782 DOI: 10.1091/mbc.e06-01-0089] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Phosphatidylinositol transfer proteins (PITPs) regulate the interface between lipid metabolism and specific steps in membrane trafficking through the secretory pathway in eukaryotes. Herein, we describe the cis-acting information that controls PITPbeta localization in mammalian cells. We demonstrate PITPbeta localizes predominantly to the trans-Golgi network (TGN) and that this localization is independent of the phospholipid-bound state of PITPbeta. Domain mapping analyses show the targeting information within PITPbeta consists of three short C-terminal specificity elements and a nonspecific membrane-binding element defined by a small motif consisting of adjacent tryptophan residues (the W(202)W(203) motif). Combination of the specificity elements with the W(202)W(203) motif is necessary and sufficient to generate an efficient TGN-targeting module. Finally, we demonstrate that PITPbeta association with the TGN is tolerant to a range of missense mutations at residue serine 262, we describe the TGN localization of a novel PITPbeta isoform with a naturally occurring S262Q polymorphism, and we find no other genetic or pharmacological evidence to support the concept that PITPbeta localization to the TGN is obligately regulated by conventional protein kinase C (PKC) or the Golgi-localized PKC isoforms delta or epsilon. These latter findings are at odds with a previous report that conventional PKC-mediated phosphorylation of residue Ser262 is required for PITPbeta targeting to Golgi membranes.
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Affiliation(s)
- Scott E. Phillips
- *Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090; and
| | - Kristina E. Ile
- *Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090; and
| | - Malika Boukhelifa
- *Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090; and
| | - Richard P.H. Huijbregts
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0021
| | - Vytas A. Bankaitis
- *Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090; and
- Address correspondence to: Vytas A. Bankaitis (
)
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25
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Michell RH, Heath VL, Lemmon MA, Dove SK. Phosphatidylinositol 3,5-bisphosphate: metabolism and cellular functions. Trends Biochem Sci 2005; 31:52-63. [PMID: 16364647 DOI: 10.1016/j.tibs.2005.11.013] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2005] [Revised: 10/26/2005] [Accepted: 11/25/2005] [Indexed: 11/16/2022]
Abstract
Polyphosphoinositides (PPIn) are low-abundance membrane phospholipids that each bind to a distinctive set of effector proteins and, thereby, regulate a characteristic suite of cellular processes. Major functions of phosphatidylinositol 3,5-bisphosphate [PtdIns(3,5)P(2)] are in membrane and protein trafficking, and in pH control in the endosome-lysosome axis. Recently identified PtdIns(3,5)P(2) effectors include a family of novel beta-propeller proteins, for which we propose the name PROPPINs [for beta-propeller(s) that binds PPIn], and possibly proteins of the epsin and CHMP (charged multi-vesicular body proteins) families. All eukaryotes, with the exception of some pathogenic protists and microsporidians, possess proteins needed for the formation, metabolism and functions of PtdIns(3,5)P(2). The importance of PtdIns(3,5)P(2) for normal cell function is underscored by recent evidence for its involvement in mammalian cell responses to insulin and for PtdIns(3,5)P(2) dysfunction in the human genetic conditions X-linked myotubular myopathy, Type-4B Charcot-Marie-Tooth disease and fleck corneal dystrophy.
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Affiliation(s)
- Robert H Michell
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK.
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Routt SM, Ryan MM, Tyeryar K, Rizzieri KE, Mousley C, Roumanie O, Brennwald PJ, Bankaitis VA. Nonclassical PITPs Activate PLD via the Stt4p PtdIns-4-kinase and Modulate Function of Late Stages of Exocytosis in Vegetative Yeast. Traffic 2005; 6:1157-72. [PMID: 16262726 DOI: 10.1111/j.1600-0854.2005.00350.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phospholipase D (PLD) is a PtdCho-hydrolyzing enzyme that plays central signaling functions in eukaryotic cells. We previously demonstrated that action of a set of four nonclassical and membrane-associated Sec14p-like phosphatidylinositol transfer proteins (PITPs) is required for optimal activation of yeast PLD in vegetative cells. Herein, we focus on mechanisms of Sfh2p and Sfh5p function in this regulatory circuit. We describe several independent lines of in vivo evidence to indicate these SFH PITPs regulate PLD by stimulating PtdIns-4,5-P2 synthesis and that this stimulated PtdIns-4,5-P2 synthesis couples to action of the Stt4p PtdIns 4-kinase. Furthermore, we provide genetic evidence to suggest that specific subunits of the yeast exocyst complex (i.e. a component of the plasma membrane vesicle docking machinery) and the Sec9p plasma membrane t-SNARE are regulated by PtdIns(4,5)P2 and that Sfh5p helps regulate this interface in vivo. The collective in vivo and biochemical data suggest SFH-mediated stimulation of Stt4p activity is indirect, most likely via a substrate delivery mechanism.
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Affiliation(s)
- Sheri M Routt
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA
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Bankaitis VA, Phillips S, Yanagisawa L, Li X, Routt S, Xie Z. Phosphatidylinositol transfer protein function in the yeast Saccharomyces cerevisiae. ACTA ACUST UNITED AC 2005; 45:155-70. [PMID: 16118014 DOI: 10.1016/j.advenzreg.2005.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PITPs regulate the interface between lipid metabolism and cellular functions, but the fundamental nature of this regulation is not understood. Yeast and mouse studies demonstrate strict coupling of individual PITPs to specific cellular activities, but the invisibility of these specificities in in vitro models for PITP activity is remarkable. In our opinion, delineation of PITP functions requires the continued application of genetic approaches such as those summarized here. Future studies dedicated to enhancing our understanding of the mechanisms of action of Sec14p-like and metazoan PITPs are worthy goals for three reasons. First, it is becoming abundantly clear that PITPs act at important biological interfaces that involve lipid and protein trafficking, phospholipid biosynthesis and polarized membrane growth. Because these interfaces are critical not only to cellular functions, but also to developmental processes, the function of PITPs in development of multicellular organisms is a particularly attractive area of research that remains essentially untapped. Second, the yeast studies indicate functional linkages between Sec14p-like PITPs and members of ubiquitous but entirely uncharacterized eukaryotic proteins such as OSBP family members. Finally, the link of PITPs to disease is already clear since PITP deficiencies lie at the foundation of novel mechanisms of neurodegenerative, glucose homeostatic and gastrointestinal disorders in mammals. Given that the contribution of Sec14p-like proteins to the PITP complement of mammalian cells is completely uninvestigated, and that the mammalian genome encodes many proteins of this class, we anticipate such advances will directly and positively impact our understanding of the molecular basis of such diseases.
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Affiliation(s)
- Vytas A Bankaitis
- Department of Cell and Developmental Biology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
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Vincent P, Chua M, Nogue F, Fairbrother A, Mekeel H, Xu Y, Allen N, Bibikova TN, Gilroy S, Bankaitis VA. A Sec14p-nodulin domain phosphatidylinositol transfer protein polarizes membrane growth of Arabidopsis thaliana root hairs. ACTA ACUST UNITED AC 2005; 168:801-12. [PMID: 15728190 PMCID: PMC2171805 DOI: 10.1083/jcb.200412074] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Phosphatidylinositol (PtdIns) transfer proteins (PITPs) regulate signaling interfaces between lipid metabolism and membrane trafficking. Herein, we demonstrate that AtSfh1p, a member of a large and uncharacterized Arabidopsis thaliana Sec14p-nodulin domain family, is a PITP that regulates a specific stage in root hair development. AtSfh1p localizes along the root hair plasma membrane and is enriched in discrete plasma membrane domains and in the root hair tip cytoplasm. This localization pattern recapitulates that visualized for PtdIns(4,5)P2 in developing root hairs. Gene ablation experiments show AtSfh1p nullizygosity compromises polarized root hair expansion in a manner that coincides with loss of tip-directed PtdIns(4,5)P2, dispersal of secretory vesicles from the tip cytoplasm, loss of the tip f-actin network, and manifest disorganization of the root hair microtubule cytoskeleton. Derangement of tip-directed Ca2+ gradients is also apparent and results from isotropic influx of Ca2+ from the extracellular milieu. We propose AtSfh1p regulates intracellular and plasma membrane phosphoinositide polarity landmarks that focus membrane trafficking, Ca2+ signaling, and cytoskeleton functions to the growing root hair apex. We further suggest that Sec14p-nodulin domain proteins represent a family of regulators of polarized membrane growth in plants.
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Affiliation(s)
- Patrick Vincent
- Department of Cell and Developmental Biology, Michael Hooker Microscopy Facility, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA.
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29
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Böhme K, Li Y, Charlot F, Grierson C, Marrocco K, Okada K, Laloue M, Nogué F. The Arabidopsis COW1 gene encodes a phosphatidylinositol transfer protein essential for root hair tip growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:686-98. [PMID: 15546352 DOI: 10.1111/j.1365-313x.2004.02245.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Root hairs are a major site for the uptake of water and nutrients into plants, and they form an increasingly important model system for the study of development in higher plants. We now report on the molecular genetic analysis of the srh1 mutant in Arabidopsis thaliana impaired in root hair tip growth. We show that srh1 is a new allele of cow1 (can of worms1) and we identified the COW1 gene using a positional cloning strategy. The N-terminus of the COW1 protein is 32% identical to an essential phosphatidylinositol transfer protein (PITP), the yeast Sec14 protein (sec14p) while the C-terminus is 34.5% identical to a late nodulin of Lotus japonicus, Nlj16. We show that expression of the COW1 lipid-binding domain complements the growth defect associated with Sec14p dysfunction in yeast. In addition, we show that GFP fused to the COW1 protein specifically accumulates at the site of root hair outgrowth. We conclude that the COW1 protein is a PITP, essential for proper root hair growth.
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Affiliation(s)
- Karen Böhme
- Station de Génétique et d'Amélioration des Plantes, INRA, Route de St Cyr, 78026 Versailles, France
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30
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Routt SM, Bankaitis VA. Biological functions of phosphatidylinositol transfer proteins. Biochem Cell Biol 2004; 82:254-62. [PMID: 15052341 DOI: 10.1139/o03-089] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol/phosphatidylcholine transfer proteins (PITPs) are ubiquitous and highly conserved proteins that are believed to regulate lipid-mediated signaling events. Their ubiquity and conservation notwithstanding, PITPs remain remarkably uninvestigated. Little is known about the coupling of specific PITPs to explicit cellular functions or the mechanisms by which PITPs interface with appropriate cellular functions. The available information indicates a role for these proteins in regulating the interface between lipid metabolism and membrane trafficking in yeast, signaling in plant development, the trafficking of specialized luminal cargo in mammalian enterocytes, and neurological function in mammals. Herein, we review recent advances in PITP biology and discuss as yet unresolved issues in this field.
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Affiliation(s)
- Sheri M Routt
- Department of Cell and Developmental Biology, School of Medicine, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, 27599-7090, USA
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31
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Holic R, Zágorsek M, Griac P. Regulation of phospholipid biosynthesis by phosphatidylinositol transfer protein Sec14p and its homologues. A critical role for phosphatidic acid. ACTA ACUST UNITED AC 2004; 271:4401-8. [PMID: 15560781 DOI: 10.1111/j.1432-1033.2004.04377.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transcription of yeast phospholipid biosynthesis structural genes, which contain an inositol-sensitive upstream activating sequence in their promoters, responds to the availability of the soluble precursors inositol and choline and to changes in phospholipid metabolism. The INO1 gene is deregulated (derepressed when inositol is present) under the conditions of increased phosphatidylcholine (PtdCho) turnover, as occurs in the sec14Delta cki1Delta strain (SEC14 encodes the major yeast phosphatidylinositol transfer protein; CKI1 encodes choline kinase of the cytidine diphosphate choline pathway of PtdCho biosynthesis). Five proteins (Sfhp) share sequence homology with phosphatidylinositol transfer protein Sec14p. Two (Sfh2p and Sfh4p), when overexpressed largely complement the otherwise essential Sec14p requirement concerning growth and secretion. In this study, we analysed the ability of Sec14 homologues to correct the defect in regulation of phospholipid biosynthesis resulting from defective or missing Sec14p. We also analysed how PtdCho turnover relates to the transcriptional regulation of phospholipid biosynthesis. The results show that (a) none of the Sec14 homologues was able to substitute for Sec14p in its regulatory aspects of phospholipid biosynthesis, (b) removal of phospholipase D activity corrected the aberrant INO1 gene regulation in yeast strains with otherwise high PtdCho turnover, and (c) increased steady-state phosphatidic acid levels correlated with derepressed levels of the INO1 gene. Overall, the results support the model in which high phosphatidic acid levels lead to derepression of the genes of phospholipid biosynthesis [Henry, S.A. & Patton-Vogt, J.L. (1998) Prog. Nucleic Acid Res. Mol. Biol.61, 133-179].
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Affiliation(s)
- Roman Holic
- Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Slovakia
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Peterman TK, Ohol YM, McReynolds LJ, Luna EJ. Patellin1, a novel Sec14-like protein, localizes to the cell plate and binds phosphoinositides. PLANT PHYSIOLOGY 2004; 136:3080-94; discussion 3001-2. [PMID: 15466235 PMCID: PMC523369 DOI: 10.1104/pp.104.045369] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Revised: 07/23/2004] [Accepted: 07/23/2004] [Indexed: 05/19/2023]
Abstract
Membrane trafficking is central to construction of the cell plate during plant cytokinesis. Consequently, a detailed understanding of the process depends on the characterization of molecules that function in the formation, transport, targeting, and fusion of membrane vesicles to the developing plate, as well as those that participate in its consolidation and maturation into a fully functional partition. Here we report the initial biochemical and functional characterization of patellin1 (PATL1), a novel cell-plate-associated protein that is related in sequence to proteins involved in membrane trafficking in other eukaryotes. Analysis of the Arabidopsis genome indicated that PATL1 is one of a small family of Arabidopsis proteins, characterized by a variable N-terminal domain followed by two domains found in other membrane-trafficking proteins (Sec14 and Golgi dynamics domains). Results from immunolocalization and biochemical fractionation studies suggested that PATL1 is recruited from the cytoplasm to the expanding and maturing cell plate. In vesicle-binding assays, PATL1 bound to specific phosphoinositides, important regulators of membrane trafficking, with a preference for phosphatidylinositol(5)P, phosphatidylinositol(4,5)P(2), and phosphatidylinositol(3)P. Taken together, these findings suggest a role for PATL1 in membrane-trafficking events associated with cell-plate expansion or maturation and point to the involvement of phosphoinositides in cell-plate biogenesis.
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Affiliation(s)
- T Kaye Peterman
- Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts 02481, USA.
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33
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Kelner A, Pekala I, Kaczanowski S, Muszynska G, Hardie DG, Dobrowolska G. Biochemical characterization of the tobacco 42-kD protein kinase activated by osmotic stress. PLANT PHYSIOLOGY 2004; 136:3255-65. [PMID: 15466234 PMCID: PMC523384 DOI: 10.1104/pp.104.046151] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 07/12/2004] [Accepted: 07/12/2004] [Indexed: 05/19/2023]
Abstract
In tobacco (Nicotiana tabacum), hyperosmotic stress induces rapid activation of a 42-kD protein kinase, referred to as Nicotiana tabacum osmotic stress-activated protein kinase (NtOSAK). cDNA encoding the kinase was cloned and, based on the predicted amino acid sequence, the enzyme was assigned to the SNF1-related protein kinase type 2 (SnRK2) family. The identity of the enzyme was confirmed by immunoprecipitation of the active kinase from tobacco cells subjected to osmotic stress using antibodies raised against a peptide corresponding to the C-terminal sequence of the kinase predicted from the cloned cDNA. A detailed biochemical characterization of NtOSAK purified from stressed tobacco cells was performed. Our results show that NtOSAK is a calcium-independent Ser/Thr protein kinase. The sequence of putative phosphorylation sites recognized by NtOSAK, predicted by the computer program PREDIKIN, resembled the substrate consensus sequence defined for animal and yeast (Saccharomyces cerevisiae) AMPK/SNF1 kinases. Our experimental data confirmed these results, as various targets for AMPK/SNF1 kinases were also efficiently phosphorylated by NtOSAK. A range of protein kinase inhibitors was tested as potential modulators of NtOSAK, but only staurosporine, a rather nonspecific protein kinase inhibitor, was found to abolish the enzyme activity. In phosphorylation reactions, NtOSAK exhibited a preference for Mg(2+) over Mn(2+) ions and an inability to use GTP instead of ATP as a phosphate donor. The enzyme activity was not modulated by 5'-AMP. To our knowledge, these results represent the first detailed biochemical characterization of a kinase of the SnRK2 family.
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Affiliation(s)
- Anna Kelner
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
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34
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Horiguchi M, Arita M, Kaempf-Rotzoll DE, Tsujimoto M, Inoue K, Arai H. pH-dependent translocation of alpha-tocopherol transfer protein (alpha-TTP) between hepatic cytosol and late endosomes. Genes Cells 2004; 8:789-800. [PMID: 14531858 DOI: 10.1046/j.1365-2443.2003.00676.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND alpha-Tocopherol transfer protein (alpha-TTP), a member of the Sec14 protein family, plays an important role in transporting alpha-tocopherol, a major lipid-soluble anti-oxidant, in the cytosolic compartment of hepatocytes and is known as a product of the causative gene for familial isolated vitamin E deficiency. It has been shown that the secretion of hepatocyte alpha-tocopherol taken up with plasma lipoproteins is facilitated by alpha-TTP. To explore the mechanism of alpha-TTP mediated alpha-tocopherol secretion, we investigated drugs which may affect this secretion. RESULTS We found that, in a hepatocyte cell culture system, intracellular alpha-tocopherol transport is impaired by chloroquine, an agent known for its function of elevating the pH in acidic compartments. Under chloroquine treatment, the diffuse cytosolic distribution of alpha-TTP changes to a punctate pattern. Double-staining experiments with endocytosis markers revealed that alpha-TTP accumulates transiently on the cytoplasmic surface of late endosomal membranes. This phenomenon is specific for hepatoma cell lines or primarily cultured hepatocytes. Other members of the Sec14 family, such as cellular retinaldehyde-binding protein (CRALBP) and supernatant protein factor (SPF), do not show this accumulation. Furthermore, we elucidate that the obligatory amino acid sequence for this function is located between amino acids 21 and 50, upstream of the N-terminal end of the lipid-binding domain. CONCLUSION We hypothesize that a liver-specific target molecule for alpha-TTP exists on the late endosomal membrane surface. This transient binding may explain the mechanism of how alpha-tocopherol is transferred from late endosomes to cytosolic alpha-TTP.
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Affiliation(s)
- Masakuni Horiguchi
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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35
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Bolte S, Brown S, Satiat-Jeunemaitre B. The N-myristoylated Rab-GTPase m-Rabmc is involved in post-Golgi trafficking events to the lytic vacuole in plant cells. J Cell Sci 2004; 117:943-54. [PMID: 14762108 DOI: 10.1242/jcs.00920] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report on the sub-cellular localisation and function of m-Rabmc, a N-myristoylated plant-specific Rab-GTPase previously characterised at the molecular level and also by structural analysis in Mesembryanthemum crystallinum. By confocal laser scanning microscopy, we identified m-Rabmc predominantly on the prevacuolar compartment of the lytic vacuole but also on the Golgi apparatus in various plant cell types. Two complementary approaches were used immunocytochemistry and cyan fluorescent protein (CFP)/yellow fluorescent protein (YFP)-fusion proteins. Co-localisation studies of m-Rabmc with a salinity stress modulated integral calcium-ATPase suggest involvement of m-Rabmc in a plant-specific transport pathway to the prevacuolar compartment of the lytic vacuole. This hypothesis was strengthened by the inhibition of the transport of aleurain fused to green fluorescent protein (GFP), a marker of the lytic vacuole, in the presence of the dominant negative mutant m-Rabmc(N147I) in Arabidopsis thaliana protoplasts. The inhibitory effect of m-Rabmc(N147I) was specific for the transport pathway to the lytic vacuole, since the transport of chitinase-YFP, a marker for the neutral vacuole, was not hindered by the mutant.
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Affiliation(s)
- Susanne Bolte
- Laboratoire de Dynamique de la Compartimentation Cellulaire, Institut des Sciences du Végétal, CNRS, UPR2355, Avenue de la Terrasse, Bâtiment 23-24, 91198 Gif-sur-Yvette Cedex, France.
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36
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Bankaitis VA, Cortese J, Phillips SE, Alb JG. Phosphatidylinositol transfer protein function in the mouse. ACTA ACUST UNITED AC 2004; 44:201-18. [PMID: 15581491 DOI: 10.1016/j.advenzreg.2003.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Vytas A Bankaitis
- Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7090, USA.
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Park CJ, Kim KJ, Shin R, Park JM, Shin YC, Paek KH. Pathogenesis-related protein 10 isolated from hot pepper functions as a ribonuclease in an antiviral pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:186-98. [PMID: 14690503 DOI: 10.1046/j.1365-313x.2003.01951.x] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
A hot pepper (Capsicum annuum) cDNA clone encoding pathogenesis-related protein 10 (CaPR-10) was isolated by differential screening of a cDNA library prepared from pepper leaves inoculated with tobacco mosaic virus pathotype (TMV-P0). CaPR-10 transcripts were induced in the incompatible interaction with TMV-P0 or Xanthomonas campestris pv. vesicatoria (Xcv) but not induced in the compatible interaction. Characterization of enzymatic properties of CaPR-10 indicated that the recombinant protein exhibits a ribonucleolytic activity against TMV RNA, as well as against pepper total RNA, and shows its putative antiviral activity in several conditions. The CaPR-10 protein existed at very low level in leaf tissue but was dramatically induced as soon as plants were inoculated with TMV-P0, and this was correlated with the increase of its ribonucleolytic activity. Immunoblot analysis and pull-down assays using proteins extracted from pepper leaves showed that TMV-P0 inoculation led to the phosphorylation of CaPR-10, a modification that should affect its capacity for RNase function. We present data that the induction and subsequent phosphorylation of CaPR-10 increased its ribonucleolytic activity to cleave invading viral RNAs, and this activity should be important to its antiviral pathway during viral attack in vivo.
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Affiliation(s)
- Chang-Jin Park
- School of Lifesciences and Biotechnology, Korea University 1, 5-ga, Anam-dong, Sungbuk-gu, Seoul 136-701, Korea
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Kempná P, Zingg JM, Ricciarelli R, Hierl M, Saxena S, Azzi A. Cloning of novel human SEC14p-like proteins: ligand binding and functional properties. Free Radic Biol Med 2003; 34:1458-72. [PMID: 12757856 DOI: 10.1016/s0891-5849(03)00173-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We describe the cloning and expression of two novel genes highly similar to the tocopherol-associated protein (hTAP/SEC14L2/SPF). Immunoprecipitation of the three recombinant hTAPs and extraction of their associated lipid-soluble molecules indicates that they bind not just tocopherols, but also phosphatidylinositol, phosphatidylcholine, and phosphatidylglycerol. Ligand competition analysis by isoelectric point mobility shift assay indicates that phosphatidylcholine, tocopherols, and tocopheryl-succinate compete with phosphatidylinositol binding to hTAPs. To investigate a possible function of hTAPs on enzymes involved in phospholipids metabolism, the activity of recombinant phosphatidylinositol 3-kinase (PI3Kgamma/p110gamma) was tested. Recombinant hTAPs reduce in vitro the activity of the recombinant catalytic subunit of PI3Kgamma and stimulate it in the presence of alpha-tocopherol up to 5-fold. Immunoprecipitation of hTAP1 from cells results in co-precipitation of PI3-kinase activity, indicating a physical contact between the two proteins at a cellular level. In summary, hTAPs may modulate, in a tocopherol-sensitive manner, phosphatidylinositol-3-kinase, a central enzyme in signal transduction, cell proliferation, and apoptosis. It is possible that other phosphatidylinositol- and phosphatidylcholine-dependent signaling pathways are modulated by hTAPs and tocopherols, possibly by transporting and presenting these ligands to the corresponding enzymes.
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Affiliation(s)
- Petra Kempná
- Institute of Biochemistry and Molecular Biology, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
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Li X, Rivas MP, Fang M, Marchena J, Mehrotra B, Chaudhary A, Feng L, Prestwich GD, Bankaitis VA. Analysis of oxysterol binding protein homologue Kes1p function in regulation of Sec14p-dependent protein transport from the yeast Golgi complex. J Cell Biol 2002; 157:63-77. [PMID: 11916983 PMCID: PMC2173257 DOI: 10.1083/jcb.200201037] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oxysterol binding proteins (OSBPs) comprise a large conserved family of proteins in eukaryotes. Their ubiquity notwithstanding, the functional activities of these proteins remain unknown. Kes1p, one of seven members of the yeast OSBP family, negatively regulates Golgi complex secretory functions that are dependent on the action of the major yeast phosphatidylinositol/phosphatidylcholine Sec14p. We now demonstrate that Kes1p is a peripheral membrane protein of the yeast Golgi complex, that localization to the Golgi complex is required for Kes1p function in vivo, and that targeting of Kes1p to the Golgi complex requires binding to a phosphoinositide pool generated via the action of the Pik1p, but not the Stt4p, PtdIns 4-kinase. Localization of Kes1p to yeast Golgi region also requires function of a conserved motif found in all members of the OSBP family. Finally, we present evidence to suggest that Kes1p may regulate adenosine diphosphate-ribosylation factor (ARF) function in yeast, and that it may be through altered regulation of ARF that Kes1p interfaces with Sec14p in controlling Golgi region secretory function.
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Affiliation(s)
- Xinmin Li
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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40
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Krugmann S, Anderson KE, Ridley SH, Risso N, McGregor A, Coadwell J, Davidson K, Eguinoa A, Ellson CD, Lipp P, Manifava M, Ktistakis N, Painter G, Thuring JW, Cooper MA, Lim ZY, Holmes AB, Dove SK, Michell RH, Grewal A, Nazarian A, Erdjument-Bromage H, Tempst P, Stephens LR, Hawkins PT. Identification of ARAP3, a novel PI3K effector regulating both Arf and Rho GTPases, by selective capture on phosphoinositide affinity matrices. Mol Cell 2002; 9:95-108. [PMID: 11804589 DOI: 10.1016/s1097-2765(02)00434-3] [Citation(s) in RCA: 230] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We show that matrices carrying the tethered homologs of natural phosphoinositides can be used to capture and display multiple phosphoinositide binding proteins in cell and tissue extracts. We present the mass spectrometric identification of over 20 proteins isolated by this method, mostly from leukocyte extracts: they include known and novel proteins with established phosphoinositide binding domains and also known proteins with surprising and unusual phosphoinositide binding properties. One of the novel PtdIns(3,4,5)P3 binding proteins, ARAP3, has an unusual domain structure, including five predicted PH domains. We show that it is a specific PtdIns(3,4,5)P3/PtdIns(3,4)P2-stimulated Arf6 GAP both in vitro and in vivo, and both its Arf GAP and Rho GAP domains cooperate in mediating PI3K-dependent rearrangements in the cell cytoskeleton and cell shape.
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Affiliation(s)
- S Krugmann
- Inositide Laboratory, The Babraham Institute, Cambridge, CB2 4AT, United Kingdom
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41
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Heilmann I, Perera IY, Gross W, Boss WF. Plasma membrane phosphatidylinositol 4,5-bisphosphate levels decrease with time in culture. PLANT PHYSIOLOGY 2001; 126:1507-18. [PMID: 11500549 PMCID: PMC117150 DOI: 10.1104/pp.126.4.1507] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2001] [Revised: 04/17/2001] [Accepted: 04/19/2001] [Indexed: 05/18/2023]
Abstract
During the stationary phase of growth, after 7 to 12 d in culture, the levels of phosphatidylinositol 4,5-bisphosphate (PtdInsP(2)) decreased by 75% in plasma membranes of the red alga Galdieria sulphuraria. Concomitant with the decrease in PtdInsP(2) levels in plasma membranes, there was an increase in PtdInsP(2) in microsomes, suggesting that the levels of plasma membrane PtdInsP(2) are regulated differentially. The decline of PtdInsP(2) in plasma membranes was accompanied by a 70% decrease in the specific activity of PtdInsP kinase and by reduced levels of protein cross-reacting with antisera against a conserved PtdInsP kinase domain. Upon osmotic stimulation, the loss of PtdInsP(2)from the plasma membrane increased from 10% in 7-d-old cells to 60% in 12-d-old cells, although the levels of inositol 1,4,5-trisphosphate (InsP(3)) produced in whole cells were roughly equal at both times. When cells with low plasma membrane PtdInsP(2) levels were osmotically stimulated, a mild osmotic stress (12.5 mM KCl) activated PtdInsP kinase prior to InsP(3) production, whereas in cells with high plasma membrane PtdInsP(2), more severe stress (250 mM KCl) was required to induce an increase in PtdInsP kinase activity. The differential regulation of a plasma membrane signaling pool of PtdInsP(2) is discussed with regard to the implications for understanding the responsive state of cells.
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Affiliation(s)
- I Heilmann
- Department of Botany, North Carolina State University, Raleigh, NC 27695-7612, USA
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42
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Kapranov P, Routt SM, Bankaitis VA, de Bruijn FJ, Szczyglowski K. Nodule-specific regulation of phosphatidylinositol transfer protein expression in Lotus japonicus. THE PLANT CELL 2001; 13:1369-82. [PMID: 11402166 PMCID: PMC135581 DOI: 10.1105/tpc.13.6.1369] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2001] [Accepted: 04/11/2001] [Indexed: 05/18/2023]
Abstract
Phosphatidylinositol transfer proteins (PITPs) modulate signal transduction pathways and membrane-trafficking functions in eukaryotes. Here, we describe the characterization of a gene family from Lotus japonicus that encodes a novel class of plant PITP-like proteins (LjPLPs) and that is regulated in an unusual nodule-specific manner. Members of this gene family were identified based on their nucleotide sequence homology with a previously described cDNA, LjNOD16, which encodes the L. japonicus late nodulin Nlj16. Nlj16 or highly related amino acid sequences are shown to constitute C-terminal domains of LjPLPs and are suggested to function as specific plasma membrane targeting modules. The expression patterns of one member of this gene family (LjPLP-IV) revealed that LjNOD16 mRNA synthesis in nodules is the result of the transcriptional activity of a nodule-specific promoter located in an intron of the LjPLP-IV gene. This intron-borne bidirectional promoter also generates nodule-specific antisense transcripts derived from the N-terminal PITP domain coding region of the LjPLP-IV gene. We propose that Nlj16 protein synthesis and LjPLP-IV antisense transcript generation are components of an elaborate mechanism designed to control LjPLP synthesis and/or functioning in nodules.
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Affiliation(s)
- P Kapranov
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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43
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Monks DE, Aghoram K, Courtney PD, DeWald DB, Dewey RE. Hyperosmotic stress induces the rapid phosphorylation of a soybean phosphatidylinositol transfer protein homolog through activation of the protein kinases SPK1 and SPK2. THE PLANT CELL 2001; 13:1205-19. [PMID: 11340192 PMCID: PMC135558 DOI: 10.1105/tpc.13.5.1205] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2000] [Accepted: 03/05/2001] [Indexed: 05/07/2023]
Abstract
Although phosphatidylinositol transfer proteins (PITPs) are known to serve critical functions in regulating a varied array of signal transduction processes in animals and yeast, the discovery of a similar class of proteins in plants occurred only recently. Here, we report the participation of Ssh1p, a soybean PITP-like protein, in the early events of osmosensory signal transduction in plants, a function not attributed previously to animal or yeast PITPs. Exposure of plant tissues to hyperosmotic stress led to the rapid phosphorylation of Ssh1p, a modification that decreased its ability to associate with membranes. An osmotic stress-activated Ssh1p kinase activity was detected in several plant species by presenting recombinant Ssh1p as a substrate in in-gel kinase assays. Elements of a similar osmosensory signaling pathway also were conserved in yeast, an observation that facilitated the identification of soybean protein kinases SPK1 and SPK2 as stress-activated Ssh1p kinases. This study reveals the activation of SPK1 and/or SPK2 and the subsequent phosphorylation of Ssh1p as two early successive events in a hyperosmotic stress-induced signaling cascade in plants. Furthermore, Ssh1p is shown to enhance the activities of a plant phosphatidylinositol 3-kinase and phosphatidylinositol 4-kinase, an observation that suggests that the ultimate function of Ssh1p in cellular signaling is to alter the plant's capacity to synthesize phosphoinositides during periods of hyperosmotic stress.
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Affiliation(s)
- D E Monks
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695, USA
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44
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Monks DE, Aghoram K, Courtney PD, DeWald DB, Dewey RE. Hyperosmotic stress induces the rapid phosphorylation of a soybean phosphatidylinositol transfer protein homolog through activation of the protein kinases SPK1 and SPK2. THE PLANT CELL 2001; 13:1205-1219. [PMID: 11340192 DOI: 10.2307/3871374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Although phosphatidylinositol transfer proteins (PITPs) are known to serve critical functions in regulating a varied array of signal transduction processes in animals and yeast, the discovery of a similar class of proteins in plants occurred only recently. Here, we report the participation of Ssh1p, a soybean PITP-like protein, in the early events of osmosensory signal transduction in plants, a function not attributed previously to animal or yeast PITPs. Exposure of plant tissues to hyperosmotic stress led to the rapid phosphorylation of Ssh1p, a modification that decreased its ability to associate with membranes. An osmotic stress-activated Ssh1p kinase activity was detected in several plant species by presenting recombinant Ssh1p as a substrate in in-gel kinase assays. Elements of a similar osmosensory signaling pathway also were conserved in yeast, an observation that facilitated the identification of soybean protein kinases SPK1 and SPK2 as stress-activated Ssh1p kinases. This study reveals the activation of SPK1 and/or SPK2 and the subsequent phosphorylation of Ssh1p as two early successive events in a hyperosmotic stress-induced signaling cascade in plants. Furthermore, Ssh1p is shown to enhance the activities of a plant phosphatidylinositol 3-kinase and phosphatidylinositol 4-kinase, an observation that suggests that the ultimate function of Ssh1p in cellular signaling is to alter the plant's capacity to synthesize phosphoinositides during periods of hyperosmotic stress.
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Affiliation(s)
- D E Monks
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695, USA
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45
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Nakase Y, Nakamura T, Hirata A, Routt SM, Skinner HB, Bankaitis VA, Shimoda C. The Schizosaccharomyces pombe spo20(+) gene encoding a homologue of Saccharomyces cerevisiae Sec14 plays an important role in forespore membrane formation. Mol Biol Cell 2001; 12:901-17. [PMID: 11294895 PMCID: PMC32275 DOI: 10.1091/mbc.12.4.901] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The Schizosaccharomyces pombe spo20-KC104 mutation was originally isolated in a screen for sporulation-deficient mutants, and the spo20-KC104 mutant exhibits temperature-sensitive growth. Herein, we report that S. pombe, spo20(+) is essential for fission yeast cell viability and is constitutively expressed throughout the life cycle. We also demonstrate that the spo20(+) gene product is structurally homologous to Saccharomyces cerevisiae Sec14, the major phosphatidylinositol transfer protein of budding yeast. This structural homology translates to a significant degree of functional relatedness because reciprocal complementation experiments demonstrate that each protein is able to fulfill the essential function of the other. Moreover, biochemical experiments show that, like Sec14, Spo20 is a phosphatidylinositol/phosphatidylcholine-transfer protein. That Spo20 is required for Golgi secretory function in vegetative cells is indicated by our demonstration that the spo20-KC104 mutant accumulates aberrant Golgi cisternae at restrictive temperatures. However, a second phenotype observed in Spo20-deficient fission yeast is arrest of cell division before completion of cell separation. Consistent with a direct role for Spo20 in controlling cell septation in vegetatively growing cells, localization experiments reveal that Spo20 preferentially localizes to the cell poles and to sites of septation of fission yeast cells. We also report that, when fission yeasts are challenged with nitrogen starvation, Spo20 translocates to the nucleus. This nuclear localization persists during conjugation and meiosis. On completion of meiosis, Spo20 translocates to forespore membranes, and it is the assembly of forespore membranes that is abnormal in spo20-KC104 cells. In such mutants, a considerable fraction of forming prespores fail to encapsulate the haploid nucleus. Our results indicate that Spo20 regulates the formation of specialized membrane structures in addition to its recognized role in regulating Golgi secretory function.
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Affiliation(s)
- Y Nakase
- Department of Biology, Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
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46
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Thomas GM, Pinxteren JA. Phosphatidylinositol transfer proteins: one big happy family or strangers with the same name? MOLECULAR CELL BIOLOGY RESEARCH COMMUNICATIONS : MCBRC 2000; 4:1-9. [PMID: 11152620 DOI: 10.1006/mcbr.2000.0253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- G M Thomas
- Department of Physiology, University College London, Rockefeller Building, 21, University Street, London, WC1E 6JJ, United Kingdom
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47
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Li X, Xie Z, Bankaitis VA. Phosphatidylinositol/phosphatidylcholine transfer proteins in yeast. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1486:55-71. [PMID: 10856713 DOI: 10.1016/s1388-1981(00)00048-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Phosphatidylinositol transfer proteins (PITPs) are now becoming widely recognized as intriguing proteins that participate in the coordination and coupling of phospholipid metabolism with vesicle trafficking, and in the regulation of important signaling cascades. Yet, only in one case is there a large body of evidence that speaks to the precise identities of PITP-dependent cellular reactions, and to the mechanisms by which PITPs execute function in eukaryotic cells. At present, yeast provide the most powerful system for analysis of the physiology of PITP function in vivo, and the mechanism by which this function is carried out. Here, we review the recent progress and remaining questions in the area of PITP function in yeast.
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Affiliation(s)
- X Li
- Department of Cell Biology, University of Alabama at Birmingham, 35294-0005, USA
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48
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Rogers DP, Bankaitis VA. Phospholipid transfer proteins and physiological functions. INTERNATIONAL REVIEW OF CYTOLOGY 2000; 197:35-81. [PMID: 10761115 DOI: 10.1016/s0074-7696(00)97002-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Issues of how cells generate and maintain unique lipid compositions in distinct intracellular membrane systems remain the subject of much study. A ubiquitous class of soluble proteins capable of transporting phospholipid monomers from membrane to membrane across an aqueous milieu has been thought to define part of the mechanism by which lipids are sorted in cells. Progress in the study of these phospholipid transfer proteins (PLTPs) raises questions regarding their physiological functions in cells and the mechanisms by which these proteins execute them. It is now clear that across the eukaryotic kingdom, members of this protein family exert essential roles in the regulation of phospholipid metabolism and central aspects of phospholipid-mediated signaling. Indeed, it is now known that dysfunction of specific PLTPs defines the basis of inherited diseases in mammals, and this list is expected to grow. Phospholipid transfer proteins, their biochemical properties, and the emerging clues regarding their physiological functions are reviewed.
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Affiliation(s)
- D P Rogers
- Department of Cell Biology, University of Alabama at Birmingham 35294, USA
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49
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Li X, Routt SM, Xie Z, Cui X, Fang M, Kearns MA, Bard M, Kirsch DR, Bankaitis VA. Identification of a novel family of nonclassic yeast phosphatidylinositol transfer proteins whose function modulates phospholipase D activity and Sec14p-independent cell growth. Mol Biol Cell 2000; 11:1989-2005. [PMID: 10848624 PMCID: PMC14898 DOI: 10.1091/mbc.11.6.1989] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Yeast phosphatidylinositol transfer protein (Sec14p) is essential for Golgi function and cell viability. We now report a characterization of five yeast SFH (Sec Fourteen Homologue) proteins that share 24-65% primary sequence identity with Sec14p. We show that Sfh1p, which shares 64% primary sequence identity with Sec14p, is nonfunctional as a Sec14p in vivo or in vitro. Yet, SFH proteins sharing low primary sequence similarity with Sec14p (i.e., Sfh2p, Sfh3p, Sfh4p, and Sfh5p) represent novel phosphatidylinositol transfer proteins (PITPs) that exhibit phosphatidylinositol- but not phosphatidylcholine-transfer activity in vitro. Moreover, increased expression of Sfh2p, Sfh4p, or Sfh5p rescues sec14-associated growth and secretory defects in a phospholipase D (PLD)-sensitive manner. Several independent lines of evidence further demonstrate that SFH PITPs are collectively required for efficient activation of PLD in vegetative cells. These include a collective requirement for SFH proteins in Sec14p-independent cell growth and in optimal activation of PLD in Sec14p-deficient cells. Consistent with these findings, Sfh2p colocalizes with PLD in endosomal compartments. The data indicate that SFH gene products cooperate with "bypass-Sec14p" mutations and PLD in a complex interaction through which yeast can adapt to loss of the essential function of Sec14p. These findings expand the physiological repertoire of PITP function in yeast and provide the first in vivo demonstration of a role for specific PITPs in stimulating activation of PLD.
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Affiliation(s)
- X Li
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA
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50
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Abstract
The past 20 years have witnessed tremendous progress in our understanding of the molecular machinery that controls protein and membrane transport between organelles (Scheckman R, Orci L. Coat proteins and vesicle budding. Science 1996;271: 1526-1533 and Rothman JE. Mechanisms of intracellular protein transport. Nature 1994;372: 55-63.) The research efforts responsible for these impressive advances have largely focused on the identification and characterization of protein factors that participate in membrane trafficking events. The role of membranes and their lipid constituents has received considerably less attention. Indeed, until rather recently, popular models for mechanisms of membrane trafficking had relegated membrane lipids to the status of a passive platform, subject to deformation by the action of coat proteins whose polymerization and depolymerization govern vesicle budding and fusion reactions. The 1990s, and particularly its last half, has brought fundamental reappraisals of the interface of lipids and lipid metabolism in regulating intracellular membrane trafficking events. Some of the emerging themes are reviewed here.
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Affiliation(s)
- R P Huijbregts
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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