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Marmorale LJ, Jin H, Reidy TG, Palomino-Alonso B, Zysnarski CJ, Jordan-Javed F, Lahiri S, Duncan MC. Fast-evolving cofactors regulate the role of HEATR5 complexes in intra-Golgi trafficking. J Cell Biol 2024; 223:e202309047. [PMID: 38240799 PMCID: PMC10798858 DOI: 10.1083/jcb.202309047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/22/2023] [Accepted: 12/18/2023] [Indexed: 01/22/2024] Open
Abstract
The highly conserved HEATR5 proteins are best known for their roles in membrane traffic mediated by the adaptor protein complex-1 (AP1). HEATR5 proteins rely on fast-evolving cofactors to bind to AP1. However, how HEATR5 proteins interact with these cofactors is unknown. Here, we report that the budding yeast HEATR5 protein, Laa1, functions in two biochemically distinct complexes. These complexes are defined by a pair of mutually exclusive Laa1-binding proteins, Laa2 and the previously uncharacterized Lft1/Yml037c. Despite limited sequence similarity, biochemical analysis and structure predictions indicate that Lft1 and Laa2 bind Laa1 via structurally similar mechanisms. Both Laa1 complexes function in intra-Golgi recycling. However, only the Laa2-Laa1 complex binds to AP1 and contributes to its localization. Finally, structure predictions indicate that human HEATR5 proteins bind to a pair of fast-evolving interacting partners via a mechanism similar to that observed in yeast. These results reveal mechanistic insight into how HEATR5 proteins bind their cofactors and indicate that Laa1 performs functions besides recruiting AP1.
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Affiliation(s)
- Lucas J Marmorale
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Huan Jin
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Thomas G Reidy
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Brandon Palomino-Alonso
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Christopher J Zysnarski
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Fatima Jordan-Javed
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Sagar Lahiri
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Ann Arbor, MI, USA
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2
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Wang C, Yang Y, Jiang C, Xi C, Yin Y, Wu H, Qian C. Exosomes Derived from hucMSCs Primed with IFN-γ Suppress the NF-κB Signal Pathway in LPS-Induced ALI by Modulating the miR-199b-5p/AFTPH Axis. Cell Biochem Biophys 2024:10.1007/s12013-023-01208-2. [PMID: 38216808 DOI: 10.1007/s12013-023-01208-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/30/2023] [Indexed: 01/14/2024]
Abstract
Exosomes (exos) are primarily responsible for the process of mesenchymal stem cells (MSCs) treatment for acute lung injury (ALI), but the mechanism remains unclear, particularly in altered microenvironment. Therefore, this study aimed to investigate the potential mechanism of exos derived from human umbilical cord mesenchymal stem cells (hucMSCs) primed with interferon-gamma (IFN-γ) on ALI and to propose a promising and cell-free strategy. This study extracted exos from hucMSCs supernatant primed and unprimed with IFN-γ marked with IFN-γ-exos and CON-exos, which were identified and traced. IFN-γ-exos administration to ALI models suppressed the NF-κB signaling pathway compared to CON-exos, which were quantified through western blot and immunohistochemical staining. Reverse transcription-quantitative polymerase chain reaction validated miR-199b-5p expression in the IFN-γ-exos and CON-exos treatment groups. Data analysis, a dual-luciferase reporter assay, and cell transfection were conducted to investigate the target binding between miR-199b-5p and Aftiphilin (AFTPH), with AFTPH expression analyzed via cell immunofluorescence and western blot. Co-immunoprecipitation was conducted for the interaction between AFTPH and NF-κB p65. The result revealed that miR-199b-5p was down-regulated in the IFN-γ-exos treatment group, which had a target binding site with AFTPH, and an interaction with NF-κB p65. Consequently, IFN-γ-exos inhibited the NF-κB signaling pathway in ALI in vitro and in vivo through the miR-199b-5p/AFTPH axis. Our results demonstrated new directions of novel and targeted treatment for ALI.
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Affiliation(s)
- Chun Wang
- Kunming Medical University, Kunming, Yunnan, China
- Department of Emergency Intensive Care Unit, Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yiran Yang
- Kunming Medical University, Kunming, Yunnan, China
| | - Chen Jiang
- Kunming Medical University, Kunming, Yunnan, China
| | - Cheng Xi
- Department of Gastrointestinal Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Yunxiang Yin
- Department of Emergency Intensive Care Unit, Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China
| | - Haiying Wu
- Department of Emergency, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China.
| | - Chuanyun Qian
- Department of Emergency, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China.
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3
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Marmorale LJ, Jin H, Reidy TG, Palomino-Alonso B, Zysnarski C, Jordan-Javed F, Lahiri S, Duncan MC. Two functionally distinct HEATR5 protein complexes are defined by fast-evolving co-factors in yeast. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554671. [PMID: 37662263 PMCID: PMC10473696 DOI: 10.1101/2023.08.24.554671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The highly conserved HEATR5 proteins are best known for their roles in membrane traffic mediated by the adaptor protein complex-1 (AP1). HEATR5 proteins rely on fast-evolving co-factors to bind to AP1. However, how HEATR5 proteins interact with these co-factors is unknown. Here, we report that the budding yeast HEATR5 protein, Laa1, functions in two biochemically distinct complexes. These complexes are defined by a pair of mutually exclusive Laa1-binding proteins, Laa2 and the previously uncharacterized Lft1/Yml037c. Despite limited sequence similarity, biochemical analysis and structure predictions indicate that Lft1 and Laa2 bind Laa1 via structurally similar mechanisms. Both Laa1 complexes function in intra-Golgi recycling. However, only the Laa2-Laa1 complex binds to AP1 and contributes to its localization. Finally, structure predictions indicate that human HEATR5 proteins bind to a pair of fast-evolving interacting partners via a mechanism similar to that observed in yeast. These results reveal mechanistic insight into how HEATR5 proteins bind their co-factors and indicate that Laa1 performs functions besides recruiting AP1.
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Affiliation(s)
- Lucas J. Marmorale
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
- Present address: Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ
| | - Huan Jin
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Thomas G. Reidy
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
- Present address: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA
| | | | | | - Fatima Jordan-Javed
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Sagar Lahiri
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
| | - Mara C Duncan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor MI
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4
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Buser DP, Spang A. Protein sorting from endosomes to the TGN. Front Cell Dev Biol 2023; 11:1140605. [PMID: 36895788 PMCID: PMC9988951 DOI: 10.3389/fcell.2023.1140605] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/09/2023] [Indexed: 02/23/2023] Open
Abstract
Retrograde transport from endosomes to the trans-Golgi network is essential for recycling of protein and lipid cargoes to counterbalance anterograde membrane traffic. Protein cargo subjected to retrograde traffic include lysosomal acid-hydrolase receptors, SNARE proteins, processing enzymes, nutrient transporters, a variety of other transmembrane proteins, and some extracellular non-host proteins such as viral, plant, and bacterial toxins. Efficient delivery of these protein cargo molecules depends on sorting machineries selectively recognizing and concentrating them for their directed retrograde transport from endosomal compartments. In this review, we outline the different retrograde transport pathways governed by various sorting machineries involved in endosome-to-TGN transport. In addition, we discuss how this transport route can be analyzed experimentally.
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Affiliation(s)
| | - Anne Spang
- Biozentrum, University of Basel, Basel, Switzerland
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5
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Shin J, Nile A, Oh JW. Role of adaptin protein complexes in intracellular trafficking and their impact on diseases. Bioengineered 2021; 12:8259-8278. [PMID: 34565296 PMCID: PMC8806629 DOI: 10.1080/21655979.2021.1982846] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
Adaptin proteins (APs) play a crucial role in intracellular cell trafficking. The 'classical' role of APs is carried out by AP1‒3, which bind to clathrin, cargo, and accessory proteins. Accordingly, AP1-3 are crucial for both vesicle formation and sorting. All APs consist of four subunits that are indispensable for their functions. In fact, based on studies using cells, model organism knockdown/knock-out, and human variants, each subunit plays crucial roles and contributes to the specificity of each AP. These studies also revealed that the sorting and intracellular trafficking function of AP can exert varying effects on pathology by controlling features such as cell development, signal transduction related to the apoptosis and proliferation pathways in cancer cells, organelle integrity, receptor presentation, and viral infection. Although the roles and functions of AP1‒3 are relatively well studied, the functions of the less abundant and more recently identified APs, AP4 and AP5, are still to be investigated. Further studies on these APs may enable a better understanding and targeting of specific diseases.APs known or suggested locations and functions.
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Affiliation(s)
- Juhyun Shin
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Arti Nile
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Jae-Wook Oh
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
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6
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Zhu T, Chen Y, Liu Z, Leng Y, Tian Y. Expression profiles and prognostic significance of AFTPH in different tumors. FEBS Open Bio 2020; 10:2666-2677. [PMID: 33090728 PMCID: PMC7714068 DOI: 10.1002/2211-5463.13003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/24/2020] [Accepted: 09/23/2020] [Indexed: 01/16/2023] Open
Abstract
Aftiphilin (AFTPH) plays an important role in regulating intracellular trafficking, exocytosis, and the pro‐inflammatory response. However, the potential prognostic role of AFTPH in cancers remains unclear. Here, we examined the expression profiles and prognostic significance of AFTPH in breast invasive carcinoma (BRCA), diffuse large B‐cell lymphoma (DLBC), lung squamous cell carcinoma (LUSC), and pancreatic adenocarcinoma (PADD) using the GEPIA and UALCAN databases. AFTPH expression was observed to be higher in cancer tissues than in normal tissues, but expression did not differ significantly between tumor stages for the four cancer types. AFTPH expression in cancer cell lines was investigated using the CCLE database; AFTPH was found to be highly expressed in four cancer cell lines. The relationship between AFTPH expression and patient prognosis was analyzed using GEPIA, LinkedOmics, and Kaplan–Meier plotter databases. Low expression of AFTPH was associated with improved prognosis for BRCA, DLBC, LUSC, and PAAD. Genetic alterations of AFTPH in cancers were explored using the cBioPortal website, revealing that gene copy number gains and amplification are common in BRCA, DLBC, LUSC, and PAAD. Related genes and markers associated with AFTPH were discovered using the LinkedOmics database. Furthermore, transfection of cells with AFTPH siRNA demonstrated that AFTPH exerts positive effects on cell proliferation in BRCA, LUSC, and PAAD cells. In conclusion, AFTPH may be a potential therapeutic target and prognostic biomarker for BRCA, DLBC, LUSC, and/or PAAD.
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Affiliation(s)
- Tengjiao Zhu
- Third Hospital of Peking University, Beijing, China
| | | | - Zhongjun Liu
- Third Hospital of Peking University, Beijing, China
| | - Yuxin Leng
- Third Hospital of Peking University, Beijing, China
| | - Yun Tian
- Third Hospital of Peking University, Beijing, China
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7
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Zysnarski CJ, Lahiri S, Javed FT, Martínez-Márquez JY, Trowbridge JW, Duncan MC. Adaptor protein complex-1 (AP-1) is recruited by the HEATR5 protein Laa1 and its co-factor Laa2 in yeast. J Biol Chem 2018; 294:1410-1419. [PMID: 30523155 DOI: 10.1074/jbc.ra118.005253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 12/03/2018] [Indexed: 11/06/2022] Open
Abstract
Cellular membrane trafficking mediated by the clathrin adaptor protein complex-1 (AP-1) is important for the proper composition and function of organelles of the endolysosomal system. Normal AP-1 function requires proteins of the HEAT repeat-containing 5 (HEATR5) family. Although HEATR5 proteins were first identified based on their ability to interact with AP-1, the functional significance of this interaction was unknown. We used bioinformatics-based phenotypic profiling and information from genome-wide fluorescence microscopy studies in the budding yeast Saccharomyces cerevisiae to identify a protein, Laa2, that mediates the interaction between AP-1 and the yeast HEATR5 protein Laa1. Further characterization of Laa2 revealed that it binds to both Laa1 and AP-1. Laa2 contains a motif similar to the characterized γ-ear-binding sites found in other AP-1-binding proteins. This motif in Laa2 is essential for the Laa1-AP-1 interaction. Moreover, mutation of this motif disrupted AP-1 localization and function and caused effects similar to mutations that remove the γ-ear of AP-1. These results indicate that Laa2 mediates the interaction between Laa1 and AP-1 and reveal that this interaction promotes the stable association of AP-1 with membranes in yeast.
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Affiliation(s)
| | - Sagar Lahiri
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109
| | - Fatima T Javed
- Cell and Developmental Biology Department, Ann Arbor, Michigan 48109
| | | | | | - Mara C Duncan
- Cell and Developmental Biology Department, Ann Arbor, Michigan 48109.
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8
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UEMURA T, SAWADA N, SAKABA T, KAMETAKA S, YAMAMOTO M, WAGURI S. Intracellular localization of GGA accessory protein p56 in cell lines and central nervous system neurons . Biomed Res 2018; 39:179-187. [DOI: 10.2220/biomedres.39.179] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Takefumi UEMURA
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine
| | - Naoki SAWADA
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine
| | - Takao SAKABA
- Department of Plastic and Reconstructive Surgery, Fukushima Medical University School of Medicine
| | - Satoshi KAMETAKA
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine
| | - Masaya YAMAMOTO
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine
| | - Satoshi WAGURI
- Department of Anatomy and Histology, Fukushima Medical University School of Medicine
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9
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Structure-based rational design of peptide inhibitors to disrupt the recognition and interaction between hepatitis B virus large envelope protein and human hepatocyte receptor γ2-adaptin. Med Chem Res 2017. [DOI: 10.1007/s00044-017-1981-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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10
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Computational design of peptide ligands to target the intermolecular interaction between viral envelope protein and pediatric receptor. Comput Biol Chem 2017; 69:120-125. [PMID: 28666141 DOI: 10.1016/j.compbiolchem.2017.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/18/2017] [Accepted: 06/12/2017] [Indexed: 01/06/2023]
Abstract
The recognition and binding of viral envelope protein to pediatric receptor subverts the membrane-trafficking apparatus to mediate virion export in young children. Here, we described a successful computational design of peptide ligands to target the intermolecular interaction between the virus large envelope protein (LHB) and adaptin receptor (ADT). Based on the crystal structure of ADT in complex with an oligopeptide segment corresponding to the core binding site of LHB, a sequence-specific amino acid preference profile was determined systematically for the ADT-binding peptides using structural bioinformatics approach. With the information harvested from the profile, a genetic evolution procedure was run to improve the biological potency of a peptide population generated randomly from the LHB. A number of potential hits were obtained from the evolution, and four were measured to interact with ADT at micromolar level. A high-affinity hit peptide was then optimized according to computational structural analysis. It is revealed that a potent peptide can be divided into three regions, i.e. a negatively charged region at N-terminus, a hydrophobic core region in middle, and a small, polar region at C-terminal tail. In addition, the two termini of peptide are partially out of the active pocket of ADT, thus contributing moderately to the peptide binding.
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11
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γ2 and γ1AP-1 complexes: Different essential functions and regulatory mechanisms in clathrin-dependent protein sorting. Eur J Cell Biol 2017; 96:356-368. [PMID: 28372831 DOI: 10.1016/j.ejcb.2017.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/24/2017] [Accepted: 03/24/2017] [Indexed: 11/20/2022] Open
Abstract
γ2 adaptin is homologous to γ1, but is only expressed in vertebrates while γ1 is found in all eukaryotes. We know little about γ2 functions and their relation to γ1. γ1 is an adaptin of the heterotetrameric AP-1 complexes, which sort proteins in and do form clathrin-coated transport vesicles and they also regulate maturation of early endosomes. γ1 knockout mice develop only to blastocysts and thus γ2 does not compensate γ1-deficiency in development. γ2 has not been classified as a clathrin-coated vesicle adaptor protein in proteome analyses and functions for monomeric γ2 in endosomal protein sorting have been proposed, but adaptin interaction studies suggested formation of heterotetrameric AP-1/γ2 complexes. We detected γ2 at the trans-Golgi network, on peripheral vesicles and identified γ2 clathrin-coated vesicles in mice. Ubiquitous σ1A and tissue-specific σ1B adaptins bind γ2 and γ1. σ1B knockout in mice does not effect γ1/σ1A AP-1 levels, but γ2/σ1A AP-1 levels are increased in brain and adipocytes. Also γ2 is essential in development. In zebrafish AP-1/γ2 and AP-1/γ1 fulfill different, essential functions in brain and the vascular system.
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12
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Chamberland JP, Antonow LT, Dias Santos M, Ritter B. NECAP2 controls clathrin coat recruitment to early endosomes for fast endocytic recycling. J Cell Sci 2016; 129:2625-37. [PMID: 27206861 DOI: 10.1242/jcs.173708] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/19/2016] [Indexed: 01/04/2023] Open
Abstract
Endocytic recycling returns receptors to the plasma membrane following internalization and is essential to maintain receptor levels on the cell surface, re-sensitize cells to extracellular ligands and for continued nutrient uptake. Yet, the protein machineries and mechanisms that drive endocytic recycling remain ill-defined. Here, we establish that NECAP2 regulates the endocytic recycling of EGFR and transferrin receptor. Our analysis of the recycling dynamics revealed that NECAP2 functions in the fast recycling pathway that directly returns cargo from early endosomes to the cell surface. In contrast, NECAP2 does not regulate the clathrin-mediated endocytosis of these cargos, the degradation of EGFR or the recycling of transferrin along the slow, Rab11-dependent recycling pathway. We show that protein knockdown of NECAP2 leads to enlarged early endosomes and causes the loss of the clathrin adapter AP-1 from the organelle. Through structure-function analysis, we define the protein-binding interfaces in NECAP2 that are crucial for AP-1 recruitment to early endosomes. Together, our data identify NECAP2 as a pathway-specific regulator of clathrin coat formation on early endosomes for fast endocytic recycling.
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Affiliation(s)
- John P Chamberland
- Boston University School of Medicine, Biochemistry Department, Boston, MA 02118, USA
| | - Lauren T Antonow
- Boston University School of Medicine, Biochemistry Department, Boston, MA 02118, USA
| | - Michel Dias Santos
- Boston University School of Medicine, Biochemistry Department, Boston, MA 02118, USA
| | - Brigitte Ritter
- Boston University School of Medicine, Biochemistry Department, Boston, MA 02118, USA
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13
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Robinson MS. Forty Years of Clathrin-coated Vesicles. Traffic 2015; 16:1210-38. [PMID: 26403691 DOI: 10.1111/tra.12335] [Citation(s) in RCA: 230] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 12/11/2022]
Abstract
The purification of coated vesicles and the discovery of clathrin by Barbara Pearse in 1975 was a landmark in cell biology. Over the past 40 years, work from many labs has uncovered the molecular details of clathrin and its associated proteins, including how they assemble into a coated vesicle and how they select cargo. Unexpected connections have been found with signalling, development, neuronal transmission, infection, immunity and genetic disorders. But there are still a number of unanswered questions, including how clathrin-mediated trafficking is regulated and how the machinery evolved.
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Affiliation(s)
- Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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14
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Mattera R, Guardia CM, Sidhu SS, Bonifacino JS. Bivalent Motif-Ear Interactions Mediate the Association of the Accessory Protein Tepsin with the AP-4 Adaptor Complex. J Biol Chem 2015; 290:30736-49. [PMID: 26542808 DOI: 10.1074/jbc.m115.683409] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Indexed: 01/11/2023] Open
Abstract
The heterotetrameric (ϵ-β4-μ4-σ4) complex adaptor protein 4 (AP-4) is a component of a non-clathrin coat involved in protein sorting at the trans-Golgi network (TGN). Considerable interest in this complex has arisen from the recent discovery that mutations in each of its four subunits are the cause of a congenital intellectual disability and movement disorder in humans. Despite its physiological importance, the structure and function of this coat remain poorly understood. To investigate the assembly of the AP-4 coat, we dissected the determinants of interaction of AP-4 with its only known accessory protein, the ENTH/VHS-domain-containing protein tepsin. Using a variety of protein interaction assays, we found that tepsin comprises two phylogenetically conserved peptide motifs, [GS]LFXG[ML]X[LV] and S[AV]F[SA]FLN, within its C-terminal unstructured region, which interact with the C-terminal ear (or appendage) domains of the β4 and ϵ subunits of AP-4, respectively. Structure-based mutational analyses mapped the binding site for the [GS]LFXG[ML]X[LV] motif to a conserved, hydrophobic surface on the β4-ear platform fold. Both peptide-ear interactions are required for efficient association of tepsin with AP-4, and for recruitment of tepsin to the TGN. The bivalency of the interactions increases the avidity of tepsin for AP-4 and may enable cross-linking of multiple AP-4 heterotetramers, thus contributing to the assembly of the AP-4 coat. In addition to revealing critical aspects of this coat, our findings extend the paradigm of peptide-ear interactions, previously established for clathrin-AP-1/AP-2 coats, to a non-clathrin coat.
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Affiliation(s)
- Rafael Mattera
- From the Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Carlos M Guardia
- From the Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Sachdev S Sidhu
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Juan S Bonifacino
- From the Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892 and
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15
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Law IKM, Bakirtzi K, Polytarchou C, Oikonomopoulos A, Hommes D, Iliopoulos D, Pothoulakis C. Neurotensin--regulated miR-133α is involved in proinflammatory signalling in human colonic epithelial cells and in experimental colitis. Gut 2015; 64:1095-104. [PMID: 25112884 PMCID: PMC4422787 DOI: 10.1136/gutjnl-2014-307329] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 07/22/2014] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Neurotensin (NT) mediates colonic inflammation through its receptor neurotensin receptor 1 (NTR1). NT stimulates miR-133α expression in colonic epithelial cells. We investigated the role of miR-133α in NT-associated colonic inflammation in vitro and in vivo. DESIGN miR-133α and aftiphilin (AFTPH) levels were measured by quantitative PCR. Antisense (as)-miR-133α was administrated intracolonicaly prior to induction of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis and dextran sodium sulfate (DSS)-induced colitis. The effect of AFTPH was examined by gene silencing in vitro. RESULTS NT increased miR-133α levels in NCM-460 overexpressing NTR1 (NCM460-NTR1) and HCT-116 cells. NT-induced p38, ERK1/2, c-Jun, and NF-κB activation, as well as IL-6, IL-8 and IL-1β messenger RNA (mRNA) expression in NCM-460-NTR1 cells were reduced in miR-133α-silenced cells, while overexpression of miR-133α reversed these effects. MiR-133α levels were increased in TNBS (2 day) and DSS (5 day) colitis, while NTR1 deficient DSS-exposed mice had reduced miR-133α levels, compared to wild-type colitic mice. Intracolonic as-miR-133α attenuated several parameters of colitis as well expression of proinflammatory mediators in the colonic mucosa. In silico search coupled with qPCR identified AFTPH as a downstream target of miR-133α, while NT decreased AFTPH expression in NCM-460-NTR1 colonocytes. Gene silencing of AFTPH enhanced NT-induced proinflammatory responses and AFTPH levels were downregulated in experimental colitis. Levels of miR-133α were significantly upregulated, while AFTPH levels were downregulated in colonic biopsies of patients with ulcerative colitis compared to controls. CONCLUSIONS NT-associated colitis and inflammatory signalling are regulated by miR-133α-AFTPH interactions. Targeting of miR-133α or AFTPH may represent a novel therapeutic approach in inflammatory bowel disease.
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Affiliation(s)
- Ivy Ka Man Law
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Kyriaki Bakirtzi
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Christos Polytarchou
- Center for Systems Biomedicine, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Angelos Oikonomopoulos
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Daniel Hommes
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Dimitrios Iliopoulos
- Center for Systems Biomedicine, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
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16
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Law IKM, Pothoulakis C. MicroRNA-133α regulates neurotensin-associated colonic inflammation in colonic epithelial cells and experimental colitis. RNA & DISEASE 2015; 2. [PMID: 26005712 DOI: 10.14800/rd.472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Ulcerative colitis (UC) and Crohn's Disease (CD) are the two most common forms of Inflammatory Bowel Diseases (IBD) marked by chronic and persistent inflammation. Neurotensin (NT), together with its receptor, NT receptor 1 (NTR1), are important mediators in intestinal inflammation and their expression is upregulated in the intestine of experimental colitis models and UC colonic biopsies. MicroRNAs (miRNAs) are short, non-coding RNA molecules which act as transcription repressors. We have previously shown that NT exposure upregulates miR-133α expression in human colonocytes NCM460 cells overexpressing NTR1 (NCM460-NTR1). Recently, miR-133α was further examined forits role in NT-associated proinflammatory signaling cascades and acute colitis in vivo. Our study shows that NT-induced miR-133α upregulation modulates NF-κB phosphorylation and promotes proinflammatory cytokine production. In addition, intracolonicinjection of antisense-miR-133α before colitis induction improves histological scores and proinflammatory cytokine transcription. More importantly, dysregulation of miR-133α levels and aftiphilin (AFTPH), a newly-identified miR-133α downstream target, is found only in UC patients, but not in patients with CD. Taken together, we identified NTR1/miR-133α/aftiphilin as a novel regulatory axis involved in NT-associated colonic inflammation in human colonocytes, acute colitis mouse model and in colonic biopsies from UC patients. Our results also provide evidence that colonic levels of NTR1, miR-133α and aftiphilin may also serve as potential biomarkers in UC.
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Affiliation(s)
- Ivy Ka Man Law
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease Center, Division of Digestive Diseases, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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17
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Zhang W, Zhang Q, Zhang M, Zhang Y, Li F, Lei P. Network analysis in the identification of special mechanisms between small cell lung cancer and non-small cell lung cancer. Thorac Cancer 2014; 5:556-64. [PMID: 26767052 DOI: 10.1111/1759-7714.12134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/04/2014] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND To explore the similar and different pathogenesis between non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). METHODS This study used bioinformatics methods, including functional enrichment analysis, compared the topological features of SCLC and NSCLC in the human protein interaction network in a system aspect, and analyzed the highly intense modules from an integrated network. RESULTS This study included 5082 and 2781 significantly different expression genes for NSCLC and SCLC, respectively. The differently expressed genes of NSCLC are mainly distributed in the extracellular region and synapse. By contrast, the genes of SCLC are located in the organelle, macromolecular complex, membrane-enclosed lumen, cell part, envelope, and synapse. Compared with SCLC, the differently expressed genes of NSCLC act in the biological regulation, multicellular organismal process, and viral reproduction and locomotion, which show that NSCLC is more likely to cause a wide range of cancer cell proliferation and virus infection than SCLC. The network topological properties of SCLC and NSCLC are similar, except the average shortest path length, which indicates that most of the genes of the two lung cancers play a similar function in the entire body. The commonly expressed genes show that all of the genes in the module may also cause NSCLC and SCLC, simultaneously. CONCLUSIONS The proteins in module will involve the same or similar biological functions and the interactions among them induce the occurrence of lung cancer. Moreover, a potential biomarker of SCLC is the interaction between APIP and apoptotic protease activating factor (APAF)1, which share a common module.
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Affiliation(s)
- Weisan Zhang
- Department of Geriatrics, Tianjin Geriatric Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Qiang Zhang
- Department of Geriatrics, Tianjin Geriatric Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Mingpeng Zhang
- Department of Geriatrics, Tianjin Geriatric Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Yun Zhang
- Department of Geriatrics, Tianjin Geriatric Institute, Tianjin Medical University General Hospital Tianjin, China
| | - Fengtan Li
- Department of Radiology, Tianjin Medical University General Hospital Tianjin, China
| | - Ping Lei
- Department of Geriatrics, Tianjin Geriatric Institute, Tianjin Medical University General Hospital Tianjin, China
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18
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The hepatitis B virus preS1 domain hijacks host trafficking proteins by motif mimicry. Nat Chem Biol 2013; 9:540-7. [PMID: 23851574 DOI: 10.1038/nchembio.1294] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/12/2013] [Indexed: 01/05/2023]
Abstract
Hepatitis B virus (HBV) is an infectious, potentially lethal human pathogen. However, there are no effective therapies for chronic HBV infections. Antiviral development is hampered by the lack of high-resolution structures for essential HBV protein-protein interactions. The interaction between preS1, an HBV surface-protein domain, and its human binding partner, γ2-adaptin, subverts the membrane-trafficking apparatus to mediate virion export. This interaction is a putative drug target. We report here atomic-resolution descriptions of the binding thermodynamics and structural biology of the interaction between preS1 and the EAR domain of γ2-adaptin. NMR, protein engineering, X-ray crystallography and MS showed that preS1 contains multiple γ2-EAR-binding motifs that mimic the membrane-trafficking motifs (and binding modes) of host proteins. These motifs localize together to a relatively rigid, functionally important region of preS1, an intrinsically disordered protein. The preS1-γ2-EAR interaction was relatively weak and efficiently outcompeted by a synthetic peptide. Our data provide the structural road map for developing peptidomimetic antivirals targeting the γ2-EAR-preS1 interaction.
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19
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Sip1, a conserved AP-1 accessory protein, is important for Golgi/endosome trafficking in fission yeast. PLoS One 2012; 7:e45324. [PMID: 23028933 PMCID: PMC3444471 DOI: 10.1371/journal.pone.0045324] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/15/2012] [Indexed: 01/20/2023] Open
Abstract
We had previously identified the mutant allele of apm1+ that encodes a homolog of the mammalian μ 1A subunit of the clathrin-associated adaptor protein-1 (AP-1) complex and demonstrated that the AP-1 complex plays a role in Golgi/endosome trafficking, secretion, and vacuole fusion in fission yeast. Here, we isolated a mutant allele of its4+/sip1+, which encodes a conserved AP-1 accessory protein. The its4-1/sip1-i4 mutants and apm1-deletion cells exhibited similar phenotypes, including sensitivity to the calcineurin inhibitor FK506, Cl− and valproic acid as well as various defects in Golgi/endosomal trafficking and cytokinesis. Electron micrographs of sip1-i4 mutants revealed vacuole fragmentation and accumulation of abnormal Golgi-like structures and secretory vesicles. Overexpression of Apm1 suppressed defective membrane trafficking in sip1-i4 mutants. The Sip1-green fluorescent protein (GFP) co-localized with Apm1-mCherry at Golgi/endosomes, and Sip1 physically interacted with each subunit of the AP-1 complex. We found that Sip1 was a Golgi/endosomal protein and the sip1-i4 mutation affected AP-1 localization at Golgi/endosomes, thus indicating that Sip1 recruited the AP-1 complex to endosomal membranes by physically interacting with each subunit of this complex. Furthermore, Sip1 is required for the correct localization of Bgs1/Cps1, 1,3-β-D-glucan synthase to polarized growth sites. Consistently, the sip1-i4 mutants displayed a severe sensitivity to micafungin, a potent inhibitor of 1,3-β-D-glucan synthase. Taken together, our findings reveal a role for Sip1 in the regulation of Golgi/endosome trafficking in coordination with the AP-1 complex, and identified Bgs1, required for cell wall synthesis, as the new cargo of AP-1-dependent trafficking.
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20
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Kametaka S, Kametaka A, Yonekura S, Haruta M, Takenoshita S, Goto S, Waguri S. AP-1 clathrin adaptor and CG8538/Aftiphilin are involved in Notch signaling during eye development in Drosophila melanogaster. J Cell Sci 2012; 125:634-48. [PMID: 22389401 DOI: 10.1242/jcs.090167] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Clathrin adaptor protein complex-1 (AP-1) and its accessory proteins play a role in the sorting of integral membrane proteins at the trans-Golgi network and endosomes. Their physiological functions in complex organisms, however, are not fully understood. In this study, we found that CG8538p, an uncharacterized Drosophila protein, shares significant structural and functional characteristics with Aftiphilin, a mammalian AP-1 accessory protein. The Drosophila Aftiphilin was shown to interact directly with the ear domain of γ-adaptin of Drosophila AP-1, but not with the GAE domain of Drosophila GGA. In S2 cells, Drosophila Aftiphilin and AP-1 formed a complex and colocalized at the Golgi compartment. Moreover, tissue-specific depletion of AP-1 or Aftiphilin in the developing eyes resulted in a disordered alignment of photoreceptor neurons in larval stage and roughened eyes with aberrant ommatidia in adult flies. Furthermore, AP-1-depleted photoreceptor neurons showed an intracellular accumulation of a Notch regulator, Scabrous, and downregulation of Notch by promoting its degradation in the lysosomes. These results suggest that AP-1 and Aftiphilin are cooperatively involved in the intracellular trafficking of Notch during eye development in Drosophila.
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Affiliation(s)
- Satoshi Kametaka
- Department of Anatomy and Histology, Fukushima Medical University, 1 Hikarigaoka, Fukushima, Fukushima 960-1295, Japan.
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21
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Hung CW, Aoh QL, Joglekar AP, Payne GS, Duncan MC. Adaptor autoregulation promotes coordinated binding within clathrin coats. J Biol Chem 2012; 287:17398-17407. [PMID: 22457357 PMCID: PMC3366796 DOI: 10.1074/jbc.m112.349035] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Membrane traffic is an essential process that allows protein and lipid exchange between the endocytic, lysosomal, and secretory compartments. Clathrin-mediated traffic between the trans-Golgi network and endosomes mediates responses to the environment through the sorting of biosynthetic and endocytic protein cargo. Traffic through this pathway is initiated by the controlled assembly of a clathrin-adaptor protein coat on the cytosolic surface of the originating organelle. In this process, clathrin is recruited by different adaptor proteins that act as a bridge between clathrin and the transmembrane cargo proteins to be transported. Interactions between adaptors and clathrin and between different types of adaptors lead to the formation of a densely packed protein network within the coat. A key unresolved issue is how the highly complex adaptor-clathrin interaction and adaptor-adaptor interaction landscape lead to the correct spatiotemporal assembly of the clathrin coat. Here we report the discovery of a new autoregulatory motif within the clathrin adaptor Gga2 that drives synergistic binding of Gga2 to clathrin and the adaptor Ent5. This autoregulation influences the temporal and/or spatial location of the Gga2-Ent5 interaction. We propose that this synergistic binding provides built-in regulation to ensure the correct assembly of clathrin coats.
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Affiliation(s)
- Chao-Wei Hung
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina 27599
| | - Quyen L Aoh
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina 27599
| | - Ajit P Joglekar
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Gregory S Payne
- Department of Biological Chemistry, The David Geffen School of Medicine at the University of California, Los Angeles, California 90095
| | - Mara C Duncan
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, North Carolina 27599.
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22
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Maritzen T, Haucke V. Gadkin: A novel link between endosomal vesicles and microtubule tracks. Commun Integr Biol 2011; 3:299-302. [PMID: 20798811 DOI: 10.4161/cib.3.4.11835] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Accepted: 03/21/2010] [Indexed: 12/21/2022] Open
Abstract
Different types of endosomal vesicles show distinct distribution patterns within cells. While early endosomes can be found throughout the cell, recycling endosomal vesicles and tubules tend to cluster near the microtubule organizing center in the perinuclear region in most cell types. The molecular mechanisms underlying the steady-state distribution and dynamics of various types of endosomal vesicles has long remained enigmatic. However, during the past decade it has become evident that microtubule-based motor proteins of the kinesin family play a pivotal role in the positioning of endosomes. Early endosomes were shown to cluster in the perinuclear area in the absence of KIF16B,1 KIF3A is required for the steady-state distribution of late endosomes/lysosomes,2 and KIF13A directs M6PR-containing vesicles from the TGN to the plasma membrane3 to name only a few examples. In the case of Tf-containing recycling endosomes antibody-injection experiments implicated kinesin-1, a heteromer comprised of KIF5 heavy and KLC light chains, as a motor for their transport towards the cell periphery.4 Indeed, KIF5B knockdown experiments confirmed that kinesin-1 is necessary to maintain the peripheral pool of recycling endosomes.5 But how is kinesin-1 linked to endosomal vesicles? Work from our own laboratory has identified the AP-1-binding protein Gadkin as a molecular link between AP-1-mediated traffic and kinesin-1-based transport along microtubules.5 This work as well as hypothetical models for kinesin-dependent endosomal membrane traffic will be discussed here.
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23
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Doolittle JM, Gomez SM. Structural similarity-based predictions of protein interactions between HIV-1 and Homo sapiens. Virol J 2010; 7:82. [PMID: 20426868 PMCID: PMC2877021 DOI: 10.1186/1743-422x-7-82] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 04/28/2010] [Indexed: 01/05/2023] Open
Abstract
Background In the course of infection, viruses such as HIV-1 must enter a cell, travel to sites where they can hijack host machinery to transcribe their genes and translate their proteins, assemble, and then leave the cell again, all while evading the host immune system. Thus, successful infection depends on the pathogen's ability to manipulate the biological pathways and processes of the organism it infects. Interactions between HIV-encoded and human proteins provide one means by which HIV-1 can connect into cellular pathways to carry out these survival processes. Results We developed and applied a computational approach to predict interactions between HIV and human proteins based on structural similarity of 9 HIV-1 proteins to human proteins having known interactions. Using functional data from RNAi studies as a filter, we generated over 2000 interaction predictions between HIV proteins and 406 unique human proteins. Additional filtering based on Gene Ontology cellular component annotation reduced the number of predictions to 502 interactions involving 137 human proteins. We find numerous known interactions as well as novel interactions showing significant functional relevance based on supporting Gene Ontology and literature evidence. Conclusions Understanding the interplay between HIV-1 and its human host will help in understanding the viral lifecycle and the ways in which this virus is able to manipulate its host. The results shown here provide a potential set of interactions that are amenable to further experimental manipulation as well as potential targets for therapeutic intervention.
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Affiliation(s)
- Janet M Doolittle
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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24
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Maritzen T, Schmidt MR, Kukhtina V, Higman VA, Strauss H, Volkmer R, Oschkinat H, Dotti CG, Haucke V. A novel subtype of AP-1-binding motif within the palmitoylated trans-Golgi network/endosomal accessory protein Gadkin/gamma-BAR. J Biol Chem 2009; 285:4074-4086. [PMID: 19965873 DOI: 10.1074/jbc.m109.049197] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Membrane traffic between the trans-Golgi network (TGN) and endosomes is mediated in part by the assembly of clathrin-AP-1 adaptor complex-coated vesicles. This process involves multiple accessory proteins that directly bind to the ear domain of AP-1gamma via degenerate peptide motifs that conform to the consensus sequence diameterG(P/D/E)(diameter/L/M) (with diameter being a large hydrophobic amino acid). Recently, gamma-BAR (hereafter referred to as Gadkin for reasons explained below) has been identified as a novel AP-1 recruitment factor involved in AP-1-dependent endosomal trafficking of lysosomal enzymes. How precisely Gadkin interacts with membranes and with AP-1gamma has remained unclear. Here we show that Gadkin is an S-palmitoylated peripheral membrane protein that lacks stable tertiary structure. S-Palmitoylation is required for the recruitment of Gadkin to TGN/endosomal membranes but not for binding to AP-1. Furthermore, we identify a novel subtype of AP-1-binding motif within Gadkin that specifically associates with the gamma1-adaptin ear domain. Mutational inactivation of this novel type of motif, either alone or in combination with three more conventional AP-1gamma binding peptides, causes Gadkin to mislocalize to the plasma membrane and interferes with its ability to render AP-1 brefeldin A-resistant, indicating its physiological importance. Our studies thus unravel the molecular basis for Gadkin-mediated AP-1 recruitment to TGN/endosomal membranes and identify a novel subtype of the AP-1-binding motif.
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Affiliation(s)
- Tanja Maritzen
- From the Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität and Charité-Universitätsmedizin Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Michael R Schmidt
- From the Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität and Charité-Universitätsmedizin Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Viktoria Kukhtina
- From the Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität and Charité-Universitätsmedizin Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Victoria A Higman
- the Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Holger Strauss
- the Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Rudolf Volkmer
- the Institut für Medizinische Immunologie, Charité-Universitätsmedizin Berlin, Hessische Strasse 3-4, 10115 Berlin, Germany
| | - Hartmut Oschkinat
- the Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Carlos G Dotti
- the Vlanders Institute for Biotechnology, Molecular & Developmental Genetics Program and Department of Human Genetics, University of Leuven Medical School, Herestraat 49, 3000 Leuven, Belgium, and
| | - Volker Haucke
- From the Institute of Chemistry and Biochemistry, Department of Membrane Biochemistry, Freie Universität and Charité-Universitätsmedizin Berlin, Takustrasse 6, 14195 Berlin, Germany; the Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.
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25
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Zhang Z, Li W. [Formation and function of Weibel-Palade bodies]. YI CHUAN = HEREDITAS 2009; 31:882-8. [PMID: 19819840 DOI: 10.3724/sp.j.1005.2009.00882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Weibel-Palade bodies (WPB) are specialized cigar-shaped secretory organelles in endothelial cells, which contain a variety of biologically active molecules. These contents can be released rapidly by stimulation and involved in hemostasis, inflammation and angiogenesis. The main component of WPB is von Willebrand factor (vWF), whose expression and tubulation are necessary for the formation of the unique rod-like WPBs. Different molecules such as vWF, P-selectin, CD63, Rab27A and Rab3D are recruited into WPB mediated by the AP-1, AP-3 or other transport machinery. The underlying mechanism of the formation of WPB remains further investigation, which will gain insights into its function. The molecular mechanism of WPB formation and its function were discussed in this review.
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Affiliation(s)
- Zhe Zhang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
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26
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Rüder C, Höpken UE, Wolf J, Mittrücker HW, Engels B, Erdmann B, Wollenzin S, Uckert W, Dörken B, Rehm A. The tumor-associated antigen EBAG9 negatively regulates the cytolytic capacity of mouse CD8+ T cells. J Clin Invest 2009; 119:2184-203. [PMID: 19620783 PMCID: PMC2719940 DOI: 10.1172/jci37760] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 05/20/2009] [Indexed: 11/17/2022] Open
Abstract
CTLs eliminate virus-infected and tumorigenic cells through exocytosis of cytotoxic agents from lytic granules. While insights into the intracellular mechanisms facilitating lytic granule release have been obtained through analysis of loss-of-function mutations in humans and mice, there is a paucity of information on negative regulators of secretory lysosome release at the molecular level. By generating and analyzing estrogen receptor-binding fragment-associated antigen 9-KO (Ebag9 KO) mice, we show here that loss of EBAG9 confers CTLs with enhanced cytolytic capacity in vitro and in vivo. Although loss of EBAG9 did not affect lymphocyte development, it led to an increase in CTL secretion of granzyme A, a marker of lytic granules. This resulted in increased cytotoxicity in vitro and an enhanced cytolytic primary and memory T cell response in vivo. We further found that EBAG9 interacts with the adaptor molecule gamma2-adaptin, suggesting EBAG9 is involved in endosomal-lysosomal biogenesis and membrane fusion. Indeed, granzyme B was sorted to secretory lysosomes more efficiently in EBAG9-deficient CTLs than it was in WT CTLs, a finding consistent with the observed enhanced kinetics of cathepsin D proteolytic processing. While EBAG9 deficiency did not disrupt the formation of the immunological synapse, lytic granules in Ebag9-/- CTLs were smaller than in WT CTLs. These data suggest that EBAG9 is a tunable inhibitor of CTL-mediated adaptive immune response functions.
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Affiliation(s)
- Constantin Rüder
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Uta E. Höpken
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Jana Wolf
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Hans-Willi Mittrücker
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Boris Engels
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Bettina Erdmann
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Susanne Wollenzin
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Wolfgang Uckert
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Bernd Dörken
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
| | - Armin Rehm
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany.
Institute for Immunology, University Medical Center, Hamburg-Eppendorf, Germany.
Universitätsmedizin Berlin, Charité, Virchow Clinics, Berlin, Germany
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Sorting of lysosomal proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2008; 1793:605-14. [PMID: 19046998 DOI: 10.1016/j.bbamcr.2008.10.016] [Citation(s) in RCA: 572] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 10/07/2008] [Accepted: 10/30/2008] [Indexed: 11/24/2022]
Abstract
Lysosomes are composed of soluble and transmembrane proteins that are targeted to lysosomes in a signal-dependent manner. The majority of soluble acid hydrolases are modified with mannose 6-phosphate (M6P) residues, allowing their recognition by M6P receptors in the Golgi complex and ensuing transport to the endosomal/lysosomal system. Other soluble enzymes and non-enzymatic proteins are transported to lysosomes in an M6P-independent manner mediated by alternative receptors such as the lysosomal integral membrane protein LIMP-2 or sortilin. Sorting of cargo receptors and lysosomal transmembrane proteins requires sorting signals present in their cytosolic domains. These signals include dileucine-based motifs, DXXLL or [DE]XXXL[LI], and tyrosine-based motifs, YXXØ, which interact with components of clathrin coats such as GGAs or adaptor protein complexes. In addition, phosphorylation and lipid modifications regulate signal recognition and trafficking of lysosomal membrane proteins. The complex interaction of both luminal and cytosolic signals with recognition proteins guarantees the specific and directed transport of proteins to lysosomes.
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28
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Lui-Roberts WWY, Ferraro F, Nightingale TD, Cutler DF. Aftiphilin and gamma-synergin are required for secretagogue sensitivity of Weibel-Palade bodies in endothelial cells. Mol Biol Cell 2008; 19:5072-81. [PMID: 18815278 DOI: 10.1091/mbc.e08-03-0301] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Formation of secretory organelles requires the coupling of cargo selection to targeting into the correct exocytic pathway. Although the assembly of regulated secretory granules is driven in part by selective aggregation and retention of content, we recently reported that adaptor protein-1 (AP-1) recruitment of clathrin is essential to the initial formation of Weibel-Palade bodies (WPBs) at the trans-Golgi network. A selective co-aggregation process might include recruitment of components required for targeting to the regulated secretory pathway. However, we find that acquisition of the regulated secretory phenotype by WPBs in endothelial cells is coupled to but can be separated from formation of the distinctive granule core by ablation of the AP-1 effectors aftiphilin and gamma-synergin. Their depletion by small interfering RNA leads to WPBs that fail to respond to secretagogue and release their content in an unregulated manner. We find that these non-responsive WPBs have density, markers of maturation, and highly multimerized von Willebrand factor similar to those of wild-type granules. Thus, by also recruiting aftiphilin/gamma-synergin in addition to clathrin, AP-1 coordinates formation of WPBs with their acquisition of a regulated secretory phenotype.
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Affiliation(s)
- Winnie W Y Lui-Roberts
- MRC Laboratory of Molecular Cell Biology, Cell Biology Unit and Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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Park JJ, Loh YP. How peptide hormone vesicles are transported to the secretion site for exocytosis. Mol Endocrinol 2008; 22:2583-95. [PMID: 18669645 DOI: 10.1210/me.2008-0209] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Post-Golgi transport of peptide hormone-containing vesicles from the site of genesis at the trans-Golgi network to the release site at the plasma membrane is essential for activity-dependent hormone secretion to mediate various endocrinological functions. It is known that these vesicles are transported on microtubules to the proximity of the release site, and they are then loaded onto an actin/myosin system for distal transport through the actin cortex to just below the plasma membrane. The vesicles are then tethered to the plasma membrane, and a subpopulation of them are docked and primed to become the readily releasable pool. Cytoplasmic tails of vesicular transmembrane proteins, as well as many cytosolic proteins including adaptor proteins, motor proteins, and guanosine triphosphatases, are involved in vesicle budding, the anchoring of the vesicles, and the facilitation of movement along the transport systems. In addition, a set of cytosolic proteins is also necessary for tethering/docking of the vesicles to the plasma membrane. Many of these proteins have been identified from different types of (neuro)endocrine cells. Here, we summarize the proteins known to be involved in the mechanisms of sorting various cargo proteins into regulated secretory pathway hormone-containing vesicles, movement of these vesicles along microtubules and actin filaments, and their eventual tethering/docking to the plasma membrane for hormone secretion.
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Affiliation(s)
- Joshua J Park
- Section on Cellular Neurobiology, National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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30
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Erpapazoglou Z, Froissard M, Nondier I, Lesuisse E, Haguenauer-Tsapis R, Belgareh-Touzé N. Substrate- and ubiquitin-dependent trafficking of the yeast siderophore transporter Sit1. Traffic 2008; 9:1372-91. [PMID: 18489705 DOI: 10.1111/j.1600-0854.2008.00766.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Eukaryotic plasma membrane transporters are subjected to a tightly regulated intracellular trafficking. The yeast siderophore iron transporter1 (Sit1) displays substrate-regulated trafficking. It is targeted to the plasma membrane or to a vacuolar degradative pathway when synthesized in the presence or absence of external substrate, respectively. Sorting of Sit1 to the vacuolar pathway is dependent on the clathrin adaptor Gga2, and more specifically on its C-GAT subdomain. Plasma membrane undergoes substrate-induced ubiquitylation dependent on the Rsp5 ubiquitin protein ligase. Sit1 is also ubiquitylated in an Rsp5-dependent manner in internal compartments when expressed in the absence of substrate. In several rsp5 mutants including cells deleted for RSP5, Sit1 expressed in the absence of substrate is correctly targeted to the endosomal pathway but its sorting to multivesicular bodies (MVBs) is impaired. Consequently, it displays endosome to plasma membrane targeting, with kinetics similar to those observed in vps mutants defective for MVB sorting. Plasma membrane Sit1 is modified by Lys63-linked ubiquitin chains. We also show for the first time in yeast that modification by this latter type of ubiquitin chains is required directly or indirectly for efficient MVB sorting, as it is for efficient internalization at the plasma membrane.
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Affiliation(s)
- Zoi Erpapazoglou
- Département de Biologie Cellulaire, Laboratoire Trafic Intracellulaire des Protéines dans la Levure, Institut Jacques Monod, UMR 7592 CNRS-Universités Paris 6 et 7, 75251 Paris cedex 05, France
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31
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Metcalf DJ, Nightingale TD, Zenner HL, Lui-Roberts WW, Cutler DF. Formation and function of Weibel-Palade bodies. J Cell Sci 2008; 121:19-27. [PMID: 18096688 DOI: 10.1242/jcs.03494] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Weibel-Palade bodies (WPBs) are secretory organelles used for post-synthesis storage in endothelial cells that can, very rapidly, be triggered to release their contents. They carry a variety of bioactive molecules that are needed to mount a rapid response to the complex environment of cells that line blood vessels. They store factors that are essential to haemostasis and inflammation, as well as factors that modulate vascular tonicity and angiogenesis. The number of WPBs and their precise content vary between endothelial tissues, reflecting their differing physiological circumstances. The particular functional demands of the highly multimerised haemostatic protein von Willebrand Factor (VWF), which is stored in WPBs as tubules until release, are responsible for the cigar shape of these granules. How VWF tubules drive the formation of these uniquely shaped organelles, and how WPB density increases during maturation, has recently been revealed by EM analysis using high-pressure freezing and freeze substitution. In addition, an AP1/clathrin coat has been found to be essential to WPB formation. Following recruitment of cargo at the TGN, there is a second wave of recruitment that delivers integral and peripheral membrane proteins to WPBs, some of which is AP3 dependent.
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Affiliation(s)
- Daniel J Metcalf
- MRC Laboratory of Molecular Cell Biology, Cell Biology Unit, University College London, Gower Street, London, WC1E 6BT, UK
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Håberg K, Lundmark R, Carlsson SR. SNX18 is an SNX9 paralog that acts as a membrane tubulator in AP-1-positive endosomal trafficking. J Cell Sci 2008; 121:1495-505. [PMID: 18411244 DOI: 10.1242/jcs.028530] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
SNX9, SNX18 and SNX30 constitute a separate subfamily of PX-BAR-containing sorting nexin (SNX) proteins. We show here that most tissues express all three paralogs, and immunoprecipitation and immunofluorescence experiments demonstrated that the SNX9-family proteins act as individual entities in cells. Their SH3 domains displayed a high selectivity for dynamin 2, and the PX-BAR units had the capacity to tubulate membranes when expressed in HeLa cells. As previously described for the PX-BAR domain of SNX9 (SNX9-PX-BAR), purified SNX18-PX-BAR caused liposome tubulation in vitro and had a binding preference for PtdIns(4,5)P(2). However, contrary to SNX9, which primarily acts in clathrin-mediated endocytosis at the plasma membrane, endogenous SNX18 localized to AP-1- and PACS1-positive endosomal structures, which were devoid of clathrin and resistant to Brefeldin A. Moreover, a gamma-adaptin recognition motif was defined in a low-complexity region of SNX18, and a complex of endogenous SNX18 and AP-1 could be immunoprecipitated after Brefeldin A treatment. Overexpression of SNX18 sequestered AP-1 from peripheral endosomes and resulted in the formation of short SNX18-decorated tubes with distinct dynamin puncta. The results indicate that SNX9-family members make up discrete membrane-scission units together with dynamin, and suggest that SNX18 mediates budding of carriers for AP-1-positive endosomal trafficking.
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Affiliation(s)
- Karin Håberg
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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33
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Olesen LE, Ford MG, Schmid EM, Vallis Y, Babu MM, Li PH, Mills IG, McMahon HT, Praefcke GJ. Solitary and Repetitive Binding Motifs for the AP2 Complex α-Appendage in Amphiphysin and Other Accessory Proteins. J Biol Chem 2008; 283:5099-109. [DOI: 10.1074/jbc.m708621200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Medigeshi GR, Krikunova M, Radhakrishnan K, Wenzel D, Klingauf J, Schu P. AP-1 Membrane–Cytoplasm Recycling Regulated by μ1A-Adaptin. Traffic 2008; 9:121-32. [DOI: 10.1111/j.1600-0854.2007.00672.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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35
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Ritter B, Denisov AY, Philie J, Allaire PD, Legendre-Guillemin V, Zylbergold P, Gehring K, McPherson PS. The NECAP PHear domain increases clathrin accessory protein binding potential. EMBO J 2007; 26:4066-77. [PMID: 17762867 PMCID: PMC2230672 DOI: 10.1038/sj.emboj.7601836] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Accepted: 07/30/2007] [Indexed: 11/08/2022] Open
Abstract
AP-2 is a key regulator of the endocytic protein machinery driving clathrin-coated vesicle (CCV) formation. One critical function, mediated primarily by the AP-2 alpha-ear, is the recruitment of accessory proteins. NECAPs are alpha-ear-binding proteins that enrich on CCVs. Here, we have solved the structure of the conserved N-terminal region of NECAP 1, revealing a unique module in the pleckstrin homology (PH) domain superfamily, which we named the PHear domain. The PHear domain binds accessory proteins bearing FxDxF motifs, which were previously thought to bind exclusively to the AP-2 alpha-ear. Structural analysis of the PHear domain reveals the molecular surface for FxDxF motif binding, which was confirmed by site-directed mutagenesis. The reciprocal analysis of the FxDxF motif in amphiphysin I identified distinct binding requirements for binding to the alpha-ear and PHear domain. We show that NECAP knockdown compromises transferrin uptake and establish a functional role for NECAPs in clathrin-mediated endocytosis. Our data uncover a striking convergence of two evolutionarily and structurally distinct modules to recognize a common peptide motif and promote efficient endocytosis.
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Affiliation(s)
- Brigitte Ritter
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Alexei Yu Denisov
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Jacynthe Philie
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Patrick D Allaire
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Valerie Legendre-Guillemin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Peter Zylbergold
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Kalle Gehring
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, Canada H3G 1Y6. Tel.: +514 398 7287; Fax: +514 847 0220; E-mail:
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Canada H3A 2B4. Tel.: +514 398 7355; Fax: +514 398 8106; E-mail:
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Krzyzaniak M, Mach M, Britt WJ. The cytoplasmic tail of glycoprotein M (gpUL100) expresses trafficking signals required for human cytomegalovirus assembly and replication. J Virol 2007; 81:10316-28. [PMID: 17626081 PMCID: PMC2045486 DOI: 10.1128/jvi.00375-07] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The virion envelope of human cytomegalovirus (HCMV) is complex and consists of an incompletely defined number of glycoproteins. The gM/gN protein complex is the most abundant protein component of the envelope. Studies have indicated that deletion of the viral gene encoding either gM or gN is a lethal mutation. Analysis of the amino acid sequence of gM disclosed a C-terminal acidic cluster of amino acids and a tyrosine-containing trafficking motif, both of which are well-described trafficking/sorting signals in the cellular secretory pathway. To investigate the roles of these signals in the trafficking of the gM/gN complex during virus assembly, we made a series of gM (UL100 open reading frame) mutants in the AD169 strain of HCMV. Mutant viruses that lacked the entire C-terminal cytoplasmic tail of gM were not viable, suggesting that the cytoplasmic tail of gM is essential for virus replication. In addition, the gM mutant protein lacking the cytoplasmic domain exhibited decreased protein stability. Mutant viruses with a deletion of the acidic cluster or alanine substitutions in tyrosine-based motifs were viable but exhibited a replication-impaired phenotype suggestive of a defect in virion assembly. Analysis of these mutant gMs using static immunofluorescence and fluorescence recovery after photobleaching demonstrated delayed kinetics of intracellular localization of the gM/gN protein to the virus assembly compartment compared to the wild-type protein. These data suggest an important role of the glycoprotein gM during virus assembly, particularly in the dynamics of gM trafficking during viral-particle assembly.
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Affiliation(s)
- Magdalena Krzyzaniak
- Department of Microbiology, University of Alabama School of Medicine, and Department of Pediatrics, Room 107, Harbor Bldg. Childrens Hospital, 1600 7th Ave. South, Birmingham, AL 35233, USA
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Mardones GA, Burgos PV, Brooks DA, Parkinson-Lawrence E, Mattera R, Bonifacino JS. The trans-Golgi network accessory protein p56 promotes long-range movement of GGA/clathrin-containing transport carriers and lysosomal enzyme sorting. Mol Biol Cell 2007; 18:3486-501. [PMID: 17596511 PMCID: PMC1951763 DOI: 10.1091/mbc.e07-02-0190] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The sorting of acid hydrolase precursors at the trans-Golgi network (TGN) is mediated by binding to mannose 6-phosphate receptors (MPRs) and subsequent capture of the hydrolase-MPR complexes into clathrin-coated vesicles or transport carriers (TCs) destined for delivery to endosomes. This capture depends on the function of three monomeric clathrin adaptors named GGAs. The GGAs comprise a C-terminal "ear" domain that binds a specific set of accessory proteins. Herein we show that one of these accessory proteins, p56, colocalizes and physically interacts with the three GGAs at the TGN. Moreover, overexpression of the GGAs enhances the association of p56 with the TGN, and RNA interference (RNAi)-mediated depletion of the GGAs decreases the TGN association and total levels of p56. RNAi-mediated depletion of p56 or the GGAs causes various degrees of missorting of the precursor of the acid hydrolase, cathepsin D. In the case of p56 depletion, this missorting correlates with decreased mobility of GGA-containing TCs. Transfection with an RNAi-resistant p56 construct, but not with a p56 construct lacking the GGA-ear-interacting motif, restores the mobility of the TCs. We conclude that p56 tightly cooperates with the GGAs in the sorting of cathepsin D to lysosomes, probably by enabling the movement of GGA-containing TCs.
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Affiliation(s)
- Gonzalo A. Mardones
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Patricia V. Burgos
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Doug A. Brooks
- Sansom Institute, University of South Australia, Adelaide, SA 5001, Australia; and
- Lysosomal Diseases Research Unit, Department of Genetic Medicine, Children Youth and Women's Health Service, North Adelaide, SA 5006, Australia
| | - Emma Parkinson-Lawrence
- Sansom Institute, University of South Australia, Adelaide, SA 5001, Australia; and
- Lysosomal Diseases Research Unit, Department of Genetic Medicine, Children Youth and Women's Health Service, North Adelaide, SA 5006, Australia
| | - Rafael Mattera
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Juan S. Bonifacino
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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38
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Kametaka S, Moriyama K, Burgos PV, Eisenberg E, Greene LE, Mattera R, Bonifacino JS. Canonical interaction of cyclin G associated kinase with adaptor protein 1 regulates lysosomal enzyme sorting. Mol Biol Cell 2007; 18:2991-3001. [PMID: 17538018 PMCID: PMC1949374 DOI: 10.1091/mbc.e06-12-1162] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The adaptor protein 1 (AP1) complex is a heterotetramer that participates in cargo sorting into clathrin-coated vesicles at the trans-Golgi network (TGN) and endosomes. The gamma subunit of AP1 possesses a C-terminal "ear" domain that recruits a cohort of accessory proteins through recognition of a shared canonical motif, PsiG[PDE][PsiLM] (where Psi is an aromatic residue). The physiological relevance of these ear-motif interactions, however, remains to be demonstrated. Here we report that the cyclin G-associated kinase (GAK) has two sequences fitting this motif, FGPL and FGEF, which mediate binding to the AP1-gamma-ear domain in vitro. Mutation of both gamma-ear-binding sequences or depletion of AP1-gamma by RNA interference (RNAi) decreases the association of GAK with the TGN in vivo. Depletion of GAK by RNAi impairs the sorting of the acid hydrolase, cathepsin D, to lysosomes. Importantly, expression of RNAi-resistant GAK restores the lysosomal sorting of cathepsin D in cells depleted of endogenous GAK, whereas expression of a similar construct bearing mutations in both gamma-ear-binding sequences fails to correct the sorting defect. Thus, interactions between the PsiG[PDE][PsiLM]-motif sequences in GAK and the AP1-gamma-ear domain are critical for the recruitment of GAK to the TGN and the function of GAK in lysosomal enzyme sorting.
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Affiliation(s)
- Satoshi Kametaka
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, and
| | - Kengo Moriyama
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, and
| | - Patricia V. Burgos
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, and
| | - Evan Eisenberg
- Laboratory of Cell Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Lois E. Greene
- Laboratory of Cell Biology, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892
| | - Rafael Mattera
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, and
| | - Juan S. Bonifacino
- *Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, and
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Inoue M, Shiba T, Ihara K, Yamada Y, Hirano S, Kamikubo H, Kataoka M, Kawasaki M, Kato R, Nakayama K, Wakatsuki S. Molecular Basis for Autoregulatory Interaction Between GAE Domain and Hinge Region of GGA1. Traffic 2007; 8:904-13. [PMID: 17506864 DOI: 10.1111/j.1600-0854.2007.00577.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Golgi-localizing, gamma-adaptin ear domain homology, ADP ribosylation factor-binding (GGA) proteins and the adaptor protein (AP) complex, AP-1, are involved in membrane traffic between the trans Golgi network and the endosomes. The gamma-adaptin ear (GAE) domain of GGAs and the gamma1 ear domain of AP-1 interact with an acidic phenylalanine motif found in accessory proteins. The GAE domain of GGA1 (GGA1-GAE) interacts with a WNSF-containing peptide derived from its own hinge region, although the peptide sequence deviates from the standard acidic phenylalanine motif. We report here the structure of GGA1-GAE in complex with the GGA1 hinge peptide, which revealed that the two aromatic side chains of the WNSF sequence fit into a hydrophobic groove formed by aliphatic portions of the side chains of conserved arginine and lysine residues of GGA1-GAE, in a similar manner to the interaction between GGA-GAEs and acidic phenylalanine sequences from the accessory proteins. Fluorescence quenching experiments indicate that the GGA1 hinge region binds to GGA1-GAE and competes with accessory proteins for binding. Taken together with the previous observation that gamma1 ear binds to the GGA1 hinge region, the interaction between the hinge region and the GAE domain underlies the autoregulation of GGA function in clathrin-mediated trafficking through competing with the accessory proteins and the AP-1 complex.
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Affiliation(s)
- Michio Inoue
- Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
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40
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Schmid EM, Ford MGJ, Burtey A, Praefcke GJK, Peak-Chew SY, Mills IG, Benmerah A, McMahon HT. Role of the AP2 beta-appendage hub in recruiting partners for clathrin-coated vesicle assembly. PLoS Biol 2007; 4:e262. [PMID: 16903783 PMCID: PMC1540706 DOI: 10.1371/journal.pbio.0040262] [Citation(s) in RCA: 188] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 06/06/2006] [Indexed: 11/19/2022] Open
Abstract
Adaptor protein complex 2 α and β-appendage domains act as hubs for the assembly of accessory protein networks involved in clathrin-coated vesicle formation. We identify a large repertoire of β-appendage interactors by mass spectrometry. These interact with two distinct ligand interaction sites on the β-appendage (the “top” and “side” sites) that bind motifs distinct from those previously identified on the α-appendage. We solved the structure of the β-appendage with a peptide from the accessory protein Eps15 bound to the side site and with a peptide from the accessory cargo adaptor β-arrestin bound to the top site. We show that accessory proteins can bind simultaneously to multiple appendages, allowing these to cooperate in enhancing ligand avidities that appear to be irreversible in vitro. We now propose that clathrin, which interacts with the β-appendage, achieves ligand displacement in vivo by self-polymerisation as the coated pit matures. This changes the interaction environment from liquid-phase, affinity-driven interactions, to interactions driven by solid-phase stability (“matricity”). Accessory proteins that interact solely with the appendages are thereby displaced to areas of the coated pit where clathrin has not yet polymerised. However, proteins such as β-arrestin (non-visual arrestin) and autosomal recessive hypercholesterolemia protein, which have direct clathrin interactions, will remain in the coated pits with their interacting receptors. Formation of clathrin-coated vesicles, important in endocytosis, relies on accessory proteins assembled by adaptor protein complex 2 (AP2). Here, mass spectrometry and crystallization identifies proteins recruited by AP2's β-appendage for this purpose.
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Affiliation(s)
- Eva M Schmid
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Marijn G. J Ford
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Anne Burtey
- Department of Infectious Diseases, Institut Cochin, Paris, France
| | - Gerrit J. K Praefcke
- Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Köln, Germany
| | - Sew-Yeu Peak-Chew
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Ian G Mills
- The Oncology Department, University of Cambridge Hutchison/MRC Cancer Research Centre, Cambridge, United Kingdom
| | | | - Harvey T McMahon
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
- * To whom correspondence should be addressed. E-mail:
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Kamikura DM, Cooper JA. Clathrin interaction and subcellular localization of Ce-DAB-1, an adaptor for protein secretion in Caenorhabditis elegans. Traffic 2006; 7:324-36. [PMID: 16497226 DOI: 10.1111/j.1600-0854.2006.00386.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Growth factors must be secreted appropriately to co-ordinate cell proliferation, specification and movement during development and to control cell numbers and migrations in adult animals. Previous results showed that the secretion of the Caenorhabditis elegans fibroblast growth factor homologue, EGL-17, from vulval precursor cells in vivo involves the cytoplasmic adaptor protein Ce-DAB-1 and two lipoprotein receptors that bind Ce-DAB-1 and EGL-17. Here, we confirm the Ce-DAB-1 requirement for EGL-17 secretion using mutant animals. In vitro, Ce-DAB-1 binds to clathrin and APT-4, the C. elegans homologue of the alpha-adaptin subunit of adaptor protein 2 (AP2), and weakly to the gamma-appendage domains of APT-1 (AP1gamma-adaptin) and APT-9 (GGA protein). In tissue-culture cells, Ce-DAB-1 localizes to various compartments, including AP2-containing vesicles near the cell surface and perinuclear vesicles that contain AP1. The latter also contain Rab8, but not Rab5 or Rab11, as well as proteins en route from the trans Golgi network (TGN) to the surface. In vivo, EGL-17 secretion was inhibited by depletion of apt-1, apt-9 or ce-rab-8 and partially inhibited by RNAi of ce-rab-5, consistent with an important role for these proteins in the secretion of EGL-17 in vivo. These results suggest that Ce-DAB-1 might co-ordinate the assembly of endocytic or secretory vesicles in vivo and may mediate EGL-17 secretion directly, by recruiting clathrin to lipoprotein receptors at the TGN, or indirectly, by affecting lipoprotein receptor endocytosis and recycling.
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Fernández GE, Payne GS. Laa1p, a conserved AP-1 accessory protein important for AP-1 localization in yeast. Mol Biol Cell 2006; 17:3304-17. [PMID: 16687571 PMCID: PMC1483057 DOI: 10.1091/mbc.e06-02-0096] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AP-1 and Gga adaptors participate in clathrin-mediated protein transport between the trans-Golgi network and endosomes. Both adaptors contain homologous domains that act to recruit accessory proteins involved in clathrin-coated vesicle formation, but the spectrum of known adaptor-binding partners is limited. This study describes an evolutionarily conserved protein of Saccharomyces cerevisiae, Laa1p (Yjl207cp), that interacts and functions specifically with AP-1. Deletion of LAA1, when combined with a conditional mutation in clathrin heavy chain or deletion of GGA genes, accentuated growth defects and increased disruption of clathrin-dependent alpha-factor maturation and transport of carboxypeptidase Y to the vacuole. In contrast, such genetic interactions were not observed between deletions of LAA1 and AP-1 subunit genes. Laa1p preferentially interacted with AP-1 compared with Gga proteins by glutathione S-transferase-fusion affinity binding and coimmunoprecipitations. Localization of AP-1 and Laa1p, but not Gga proteins, was highly sensitive to brefeldin A, an inhibitor of ADP-ribosylation factor (Arf) activation. Importantly, deletion of LAA1 caused mislocalization of AP-1, especially in cells at high density (postdiauxic shift), but it did not affect Gga protein distribution. Our results identify Laa1p as a new determinant of AP-1 localization, suggesting a model in which Laa1p and Arf cooperate to direct stable association of AP-1 with appropriate intracellular membranes.
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Affiliation(s)
- G. Esteban Fernández
- Department of Biological Chemistry, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
| | - Gregory S. Payne
- Department of Biological Chemistry, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA 90095
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Traub LM. Common principles in clathrin-mediated sorting at the Golgi and the plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1744:415-37. [PMID: 15922462 DOI: 10.1016/j.bbamcr.2005.04.005] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 04/17/2005] [Accepted: 04/19/2005] [Indexed: 12/12/2022]
Abstract
Clathrin-mediated vesicular trafficking events underpin the vectorial transfer of macromolecules between several eukaryotic membrane-bound compartments. Classical models for coat operation, focused principally on interactions between clathrin, the heterotetrameric adaptor complexes, and cargo molecules, fail to account for the full complexity of the coat assembly and sorting process. New data reveal that targeting of clathrin adaptor complexes is generally supported by phosphoinositides, that cargo recognition by heterotetrameric adaptors depends on phosphorylation-driven conformational alterations, and that dedicated clathrin-associated sorting proteins (CLASPs) exist to promote the selective trafficking of specific categories of cargo. A host of accessory factors also participate in coat polymerization events, and the independently folded appendage domains that project off the heterotetrameric adaptor core function as recruitment platforms that appear to oversee assembly operations. It is also now clear that focal polymerization of branched actin microfilaments contributes to clathrin-coated vesicle assembly and movement at both plasma membrane and Golgi sites. This improved appreciation of the complex mechanisms governing clathrin-dependent sorting events reveals several common principles of clathrin operation at the Golgi and the plasma membrane.
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Affiliation(s)
- Linton M Traub
- Department of Cell Biology and Physiology University of Pittsburgh School of Medicine 3500 Terrace Street, S325BST Pittsburgh, PA 15206, USA.
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Knodler LA, Steele-Mortimer O. The Salmonella effector PipB2 affects late endosome/lysosome distribution to mediate Sif extension. Mol Biol Cell 2005; 16:4108-23. [PMID: 15987736 PMCID: PMC1196323 DOI: 10.1091/mbc.e05-04-0367] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
After internalization into mammalian cells, the bacterial pathogen Salmonella enterica resides within a membrane-bound compartment, the Salmonella-containing vacuole (SCV). During its maturation process, the SCV interacts extensively with host cell endocytic compartments, especially late endosomes/lysosomes (LE/Lys) at later stages. These interactions are mediated by the activities of multiple bacterial and host cell proteins. Here, we show that the Salmonella type III effector PipB2 reorganizes LE/Lys compartments in mammalian cells. This activity results in the centrifugal extension of lysosomal glycoprotein-rich membrane tubules, known as Salmonella-induced filaments, away from the SCV along microtubules. Salmonella overexpressing pipB2 induce the peripheral accumulation of LE/Lys compartments, reducing the frequency of LE/Lys tubulation. Furthermore, ectopic expression of pipB2 redistributes LE/Lys, but not other cellular organelles, to the cell periphery. In coexpression studies, PipB2 can overcome the effects of dominant-active Rab7 or Rab34 on LE/Lys positioning. Deletion of a C-terminal pentapeptide motif of PipB2, LFNEF, prevents its peripheral targeting and effect on organelle positioning. The PipB2 homologue PipB does not possess this motif or the same biological activity as PipB2. Therefore, it seems that a divergence in the biological functions of these two effectors can be accounted for by sequence divergence in their C termini.
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Affiliation(s)
- Leigh A Knodler
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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Burman JL, Wasiak S, Ritter B, de Heuvel E, McPherson PS. Aftiphilin is a component of the clathrin machinery in neurons. FEBS Lett 2005; 579:2177-84. [PMID: 15811338 DOI: 10.1016/j.febslet.2005.03.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Revised: 03/03/2005] [Accepted: 03/03/2005] [Indexed: 11/20/2022]
Abstract
Aftiphilin was identified through a database search for proteins containing binding motifs for the gamma-ear domain of clathrin adaptor protein 1 (AP-1). Here, we demonstrate that aftiphilin is expressed predominantly in brain where it is enriched on clathrin-coated vesicles. In addition to eight gamma-ear-binding motifs, aftiphilin contains two WXXF-acidic motifs that mediate binding to the alpha-ear of clathrin adaptor protein 2 (AP-2) and three FXXFXXF/L motifs that mediate binding to the alpha- and beta2-ear. We demonstrate that aftiphilin uses these motifs for interactions with AP-1 and AP-2 and that it immunoprecipitates these APs but not AP-3 or AP-4 from brain extracts. Aftiphilin demonstrates a brefeldin A sensitive localization to the trans-Golgi network in hippocampal neurons where it co-localizes with AP-1. Aftiphilin is also found at synapses where it co-localizes with synaptophysin and AP-2. Our data suggest a role for aftiphilin in clathrin-mediated trafficking in neurons.
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Affiliation(s)
- Jonathon L Burman
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Que., Canada H3A 2B4
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Hirst J, Borner GHH, Harbour M, Robinson MS. The aftiphilin/p200/gamma-synergin complex. Mol Biol Cell 2005; 16:2554-65. [PMID: 15758025 PMCID: PMC1087257 DOI: 10.1091/mbc.e04-12-1077] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 02/11/2005] [Accepted: 02/24/2005] [Indexed: 11/11/2022] Open
Abstract
Aftiphilin is a protein that was recently identified in database searches for proteins with motifs that interact with AP-1 and clathrin, but its function is unknown. Here we demonstrate that aftiphilin has a second, atypical clathrin binding site, YQW, that colocalizes with AP-1 by immunofluorescence, and that is enriched in clathrin-coated vesicles (CCVs), confirming that it is a bona fide component of the CCV machinery. By gel filtration, aftiphilin coelutes with two other AP-1 binding partners, p200a and gamma-synergin. Antibodies against any one of these three proteins immunoprecipitate the other two, and knocking down any of the three proteins by siRNA causes a reduction in the levels of the other two, indicating that they form a stable complex. Like AP-1-depleted cells, aftiphilin-depleted cells missort a CD8-furin chimera and the lysosomal enzyme cathepsin D. However, whereas AP-1-depleted cells recycle endocytosed transferrin more slowly than untreated cells, aftiphilin-depleted cells accumulate endocytosed transferrin in a peripheral compartment and recycle it more rapidly. These observations show that in general, the aftiphilin/p200/gamma-synergin complex facilitates AP-1 function, but the complex may have additional functions as well, because of the opposing effects of the two knockdowns on transferrin recycling.
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Affiliation(s)
- Jennifer Hirst
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 2XY, United Kingdom
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47
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Neubrand VE, Will RD, Möbius W, Poustka A, Wiemann S, Schu P, Dotti CG, Pepperkok R, Simpson JC. Gamma-BAR, a novel AP-1-interacting protein involved in post-Golgi trafficking. EMBO J 2005; 24:1122-33. [PMID: 15775984 PMCID: PMC556403 DOI: 10.1038/sj.emboj.7600600] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Accepted: 02/04/2005] [Indexed: 01/31/2023] Open
Abstract
A novel peripheral membrane protein (2c18) that interacts directly with the gamma 'ear' domain of the adaptor protein complex 1 (AP-1) in vitro and in vivo is described. Ultrastructural analysis demonstrates a colocalization of 2c18 and gamma1-adaptin at the trans-Golgi network (TGN) and on vesicular profiles. Overexpression of 2c18 increases the fraction of membrane-bound gamma1-adaptin and inhibits its release from membranes in response to brefeldin A. Knockdown of 2c18 reduces the steady-state levels of gamma1-adaptin on membranes. Overexpression or downregulation of 2c18 leads to an increased secretion of the lysosomal hydrolase cathepsin D, which is sorted by the mannose-6-phosphate receptor at the TGN, which itself involves AP-1 function for trafficking between the TGN and endosomes. This suggests that the direct interaction of 2c18 and gamma1-adaptin is crucial for membrane association and thus the function of the AP-1 complex in living cells. We propose to name this protein gamma-BAR.
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Affiliation(s)
- Veronika E Neubrand
- Cell Biology and Cell Biophysics Programme, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Rainer D Will
- Molecular Genome Analysis, German Cancer Research Centre, Heidelberg, Germany
| | - Wiebke Möbius
- Max Planck Institute for Experimental Medicine, Neurogenetics, Göttingen, Germany
| | - Annemarie Poustka
- Molecular Genome Analysis, German Cancer Research Centre, Heidelberg, Germany
| | - Stefan Wiemann
- Molecular Genome Analysis, German Cancer Research Centre, Heidelberg, Germany
| | - Peter Schu
- Zentrum fuer Biochemie und Molekulare Zellbiologie, Department Biochemie II, Universitaet Göttingen, Goettingen, Germany
| | - Carlos G Dotti
- Cavalieri Ottolenghi Scientific Institute, Unversita degli Studi di Torino, AO San Luigi Gonzaga, Orbassano (Torino), Italy
| | - Rainer Pepperkok
- Cell Biology and Cell Biophysics Programme, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Cell Biology and Cell Biophysics Programme, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany. Tel.: +49 6221 387 8332; Fax: +49 6221 387 8306; E-mail:
| | - Jeremy C Simpson
- Cell Biology and Cell Biophysics Programme, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
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Abstract
Clathrin-coated vesicles (CCVs) are responsible for the transport of proteins between various compartments of the secretory and endocytic systems. Clathrin forms a scaffold around these vesicles that is linked to membranes by clathrin adaptors. The adaptors simultaneously bind to clathrin and to transmembrane proteins and/or phospholipids and can also interact with each other and with other components of the CCV formation machinery. The result is a collection of proteins that can make multiple, moderate strength (microM Kd) interactions and thereby establish the dynamic regulatable networks to drive vesicle genesis at the correct time and place in the cell. This review focuses on the structure of clathrin adaptors and how these structures provide functional information on the mechanism of CCV formation.
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Affiliation(s)
- David J Owen
- Cambridge Institute for Medical Research, Department of Clinical Biochemistry, University of Cambridge, Cambridge CB2 2XY, UK.
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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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Mishra SK, Hawryluk MJ, Brett TJ, Keyel PA, Dupin AL, Jha A, Heuser JE, Fremont DH, Traub LM. Dual Engagement Regulation of Protein Interactions with the AP-2 Adaptor α Appendage. J Biol Chem 2004; 279:46191-203. [PMID: 15292237 DOI: 10.1074/jbc.m408095200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Clathrin-mediated endocytosis depends upon the coordinated assembly of a large number of discrete clathrin coat components to couple cargo selection with rapid internalization from the cell surface. Accordingly, the heterotetrameric AP-2 adaptor complex binds not only to clathrin and select cargo molecules, but also to an extensive family of endocytic accessory factors and alternate sorting adaptors. Physical associations between accessory proteins and AP-2 occur primarily through DP(F/W) or FXDXF motifs, which engage an interaction surface positioned on the C-terminal platform subdomain of the independently folded alpha subunit appendage. Here, we find that the WXX(F/W)X(D/E) interaction motif found in several endocytic proteins, including synaptojanin 1, stonin 2, AAK1, GAK, and NECAP1, binds a second interaction site on the bilobal alpha appendage, located on the N-terminal beta sandwich subdomain. Both alpha appendage binding sites can be engaged synchronously, and our data reveal that varied assemblies of interaction motifs with different affinities for two sites upon the alpha appendage can provide a mechanism for temporal ordering of endocytic accessory proteins during clathrin-mediated endocytosis.
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Affiliation(s)
- Sanjay K Mishra
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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