1
|
Chandra M, Kendall AK, Ford MGJ, Jackson LP. VARP binds SNX27 to promote endosomal supercomplex formation on membranes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.11.603126. [PMID: 39026782 PMCID: PMC11257539 DOI: 10.1101/2024.07.11.603126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Multiple essential membrane trafficking pathways converge at endosomes to maintain cellular homeostasis by sorting critical transmembrane cargo proteins to the plasma membrane or the trans-Golgi network (TGN). The Retromer heterotrimer (VPS26/VPS35/VPS29 subunits) binds multiple sorting nexin (SNX) proteins on endosomal membranes, but molecular mechanisms regarding formation and regulation of metazoan SNX/Retromer complexes have been elusive. Here, we combine biochemical and biophysical approaches with AlphaFold2 Multimer modeling to identify a direct interaction between the VARP N-terminus and SNX27 PDZ domain. VARP and SNX27 interact with high nanomolar affinity using the binding pocket established for PDZ binding motif (PDZbm) cargo. Specific point mutations in VARP abrogate the interaction in vitro. We further establish a full biochemical reconstitution system using purified mammalian proteins to directly and systematically test whether multiple endosomal coat complexes are recruited to membranes to generate tubules. We successfully use purified coat components to demonstrate which combinations of Retromer with SNX27, ESCPE-1 (SNX2/SNX6), or both complexes can remodel membranes containing physiological cargo motifs and phospholipid composition. SNX27, alone and with Retromer, induces tubule formation in the presence of PI(3)P and PDZ cargo motifs. ESCPE-1 deforms membranes enriched with Folch I and CI-MPR cargo motifs, but surprisingly does not recruit Retromer. Finally, we find VARP is required to reconstitute a proposed endosomal "supercomplex" containing SNX27, ESCPE-1, and Retromer on PI(3)P-enriched membranes. These data suggest VARP functions as a key regulator in metazoans to promote cargo sorting out of endosomes.
Collapse
Affiliation(s)
- Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Marijn G J Ford
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| |
Collapse
|
2
|
Min WK, Kwon DH, Song JT, Seo HS. Arabidopsis retromer subunit AtVPS29 is involved in SLY1-mediated gibberellin signaling. PLANT CELL REPORTS 2024; 43:53. [PMID: 38315261 PMCID: PMC10844355 DOI: 10.1007/s00299-024-03144-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 12/31/2023] [Indexed: 02/07/2024]
Abstract
KEY MESSAGE Retromer protein AtVPS29 upregulates the SLY1 protein and downregulates the RGA protein, positively stimulating the development of the root meristematic zone, which indicates an important role of AtVPS29 in gibberellin signaling. In plants, the large retromer complex is known to play roles in multiple development processes, including cell polarity, programmed cell death, and root hair growth in Arabidopsis. However, many of its roles in plant development remain unknown. Here, we show that Arabidopsis trimeric retromer protein AtVPS29 (vacuolar protein sorting 29) modulates gibberellin signaling. The SLEEPY1 (SLY1) protein, known as a positive regulator of gibberellic acid (GA) signaling, exhibited lower abundance in vps29-3 mutants compared to wild-type (WT) plants. Conversely, the DELLA repressor protein, targeted by the E3 ubiquitin ligase SCF (Skp, Cullin, F-box) complex and acting as a negative regulator of GA signaling, showed increased abundance in vps29-3 mutants compared to WT. The vps29-3 mutants exhibited decreased sensitivity to exogenous GA supply in contrast to WT, despite an upregulation in the expression of GA receptor genes within the vps29-3 mutants. In addition, the expression of the GA synthesis genes was downregulated in vps29-3 mutants, implying that the loss of AtVPS29 causes the downregulation of GA synthesis and signaling. Furthermore, vps29-3 mutants exhibited a reduced meristematic zone accompanied by a decreased cell number. Together, these data indicate that AtVPS29 positively regulates SLY1-mediated GA signaling and plant growth.
Collapse
Affiliation(s)
- Wang Ki Min
- Department of Agriculture, Forestry and Bioresources, College of Agriculture and Life Sciences, Seoul National University, Gwanakro 200, Gwanak-Gu, Seoul, 08826, Korea
| | - Dae Hwan Kwon
- Department of Agriculture, Forestry and Bioresources, College of Agriculture and Life Sciences, Seoul National University, Gwanakro 200, Gwanak-Gu, Seoul, 08826, Korea
| | - Jong Tae Song
- Department of Applied Biosciences, Kyungpook National University, Daegu, 41566, Korea
| | - Hak Soo Seo
- Department of Agriculture, Forestry and Bioresources, College of Agriculture and Life Sciences, Seoul National University, Gwanakro 200, Gwanak-Gu, Seoul, 08826, Korea.
| |
Collapse
|
3
|
Huang J, Tiu AC, Jose PA, Yang J. Sorting nexins: role in the regulation of blood pressure. FEBS J 2023; 290:600-619. [PMID: 34847291 PMCID: PMC9149145 DOI: 10.1111/febs.16305] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 10/13/2021] [Accepted: 11/29/2021] [Indexed: 02/06/2023]
Abstract
Sorting nexins (SNXs) are a family of proteins that regulate cellular cargo sorting and trafficking, maintain intracellular protein homeostasis, and participate in intracellular signaling. SNXs are also important in the regulation of blood pressure via several mechanisms. Aberrant expression and dysfunction of SNXs participate in the dysregulation of blood pressure. Genetic studies show a correlation between SNX gene variants and the response to antihypertensive drugs. In this review, we summarize the progress in SNX-mediated regulation of blood pressure, discuss the potential role of SNXs in the pathophysiology and treatment of hypertension, and propose novel strategies for the medical therapy of hypertension.
Collapse
Affiliation(s)
- Juan Huang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing 410020, P.R. China
| | - Andrew C. Tiu
- Department of Medicine, Einstein Medical Center Philadelphia, Philadelphia, PA 19141, USA
| | - Pedro A. Jose
- Division of Renal Diseases & Hypertension, Department of Medicine, and Department of Physiology and Pharmacology, The George Washington University School of Medicine & Health Sciences, Washington, DC 20052, USA
| | - Jian Yang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing 410020, P.R. China
| |
Collapse
|
4
|
Kendall AK, Chandra M, Xie B, Wan W, Jackson LP. Improved mammalian retromer cryo-EM structures reveal a new assembly interface. J Biol Chem 2022; 298:102523. [PMID: 36174678 PMCID: PMC9636581 DOI: 10.1016/j.jbc.2022.102523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 08/30/2022] [Accepted: 09/03/2022] [Indexed: 12/05/2022] Open
Abstract
Retromer (VPS26/VPS35/VPS29 subunits) assembles with multiple sorting nexin proteins on membranes to mediate endosomal recycling of transmembrane protein cargoes. Retromer has been implicated in other cellular processes, including mitochondrial homeostasis, nutrient sensing, autophagy, and fission events. Mechanisms for mammalian retromer assembly remain undefined, and retromer engages multiple sorting nexin proteins to sort cargoes to different destinations. Published structures demonstrate mammalian retromer forms oligomers in vitro, but several structures were poorly resolved. We report here improved retromer oligomer structures using single-particle cryo-EM by combining data collected from tilted specimens with multiple advancements in data processing, including using a 3D starting model for enhanced automated particle picking in RELION. We used a retromer mutant (3KE retromer) that breaks VPS35-mediated interfaces to determine a structure of a new assembly interface formed by the VPS26A and VPS35 N-termini. The interface reveals how an N-terminal VPS26A arrestin saddle can link retromer chains by engaging a neighboring VPS35 N- terminus, on the opposite side from the well-characterized C-VPS26/N-VPS35 interaction observed within heterotrimers. The new interaction interface exhibits substantial buried surface area (∼7000 Å2) and further suggests that metazoan retromer may serve as an adaptable scaffold.
Collapse
Affiliation(s)
- Amy K Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Boyang Xie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - William Wan
- Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
| |
Collapse
|
5
|
Brunori M, Gianni S. An Outlook on the Complexity of Protein Morphogenesis in Health and Disease. Front Mol Biosci 2022; 9:909567. [PMID: 35769915 PMCID: PMC9234464 DOI: 10.3389/fmolb.2022.909567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/28/2022] [Indexed: 11/21/2022] Open
Abstract
The study of the mechanisms whereby proteins achieve their native functionally competent conformation has been a key issue in molecular biosciences over the last 6 decades. Nevertheless, there are several debated issues and open problems concerning some aspects of this fundamental problem. By considering the emerging complexity of the so-called “native state,” we attempt hereby to propose a personal account on some of the key topics in the field, ranging from the relationships between misfolding and diseases to the significance of protein disorder. Finally, we briefly describe the recent and exciting advances in predicting protein structures from their amino acid sequence.
Collapse
Affiliation(s)
- Maurizio Brunori
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche “A. Rossi Fanelli” and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università, Rome, Italy
- Accademia Nazionale dei Lincei, Rome, Italy
- *Correspondence: Maurizio Brunori,
| | - Stefano Gianni
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche “A. Rossi Fanelli” and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università, Rome, Italy
| |
Collapse
|
6
|
Genetic disorders of cellular trafficking. Trends Genet 2022; 38:724-751. [DOI: 10.1016/j.tig.2022.02.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 02/11/2022] [Accepted: 02/28/2022] [Indexed: 02/06/2023]
|
7
|
Chandra M, Kendall AK, Jackson LP. Toward Understanding the Molecular Role of SNX27/Retromer in Human Health and Disease. Front Cell Dev Biol 2021; 9:642378. [PMID: 33937239 PMCID: PMC8083963 DOI: 10.3389/fcell.2021.642378] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/22/2021] [Indexed: 11/30/2022] Open
Abstract
Aberrations in membrane trafficking pathways have profound effects in cellular dynamics of cellular sorting processes and can drive severe physiological outcomes. Sorting nexin 27 (SNX27) is a metazoan-specific sorting nexin protein from the PX-FERM domain family and is required for endosomal recycling of many important transmembrane receptors. Multiple studies have shown SNX27-mediated recycling requires association with retromer, one of the best-known regulators of endosomal trafficking. SNX27/retromer downregulation is strongly linked to Down's Syndrome (DS) via glutamate receptor dysfunction and to Alzheimer's Disease (AD) through increased intracellular production of amyloid peptides from amyloid precursor protein (APP) breakdown. SNX27 is further linked to addiction via its role in potassium channel trafficking, and its over-expression is linked to tumorigenesis, cancer progression, and metastasis. Thus, the correct sorting of multiple receptors by SNX27/retromer is vital for normal cellular function to prevent human diseases. The role of SNX27 in regulating cargo recycling from endosomes to the cell surface is firmly established, but how SNX27 assembles with retromer to generate tubulovesicular carriers remains elusive. Whether SNX27/retromer may be a putative therapeutic target to prevent neurodegenerative disease is now an emerging area of study. This review will provide an update on our molecular understanding of endosomal trafficking events mediated by the SNX27/retromer complex on endosomes.
Collapse
Affiliation(s)
- Mintu Chandra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Amy K. Kendall
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Lauren P. Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
| |
Collapse
|
8
|
Find your coat: Using correlative light and electron microscopy to study intracellular protein coats. Curr Opin Cell Biol 2021; 71:21-28. [PMID: 33684808 DOI: 10.1016/j.ceb.2021.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/14/2022]
Abstract
Protein coats, important for vesicular trafficking in eukaryotic cells, help shape membranes and package cargo. But their dynamic construction cannot be fully understood until the distinct steps of their assembly in their native intracellular context at molecular resolution can be visualized. For this, correlative light and electron microscopy (CLEM) is an essential tool. Here, we discuss how emerging CLEM techniques have been used to study the assembly of protein coats inside cells. We review how current and developing CLEM technologies are poised to answer fundamental questions of protein coat architecture at the nanoscale.
Collapse
|
9
|
Abstract
For decades, recycling of membrane proteins has been represented in figures by arrows between the "endosome" and the plasma membrane, but recently there has been an explosion in the understanding of the mechanisms and protein complexes required to facilitate protein recycling. Here, some key discoveries will be introduced, including assigning function to a number of recently recognized protein complexes and linking their function to protein recycling. Furthermore, the importance of lipid interactions and links to diseases and epithelial polarity will be summarized.
Collapse
Affiliation(s)
- Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| |
Collapse
|