scholarly journals Retromer stabilizes transient membrane insertion of L2 capsid protein during retrograde entry of human papillomavirus

2021 ◽  
Vol 7 (27) ◽  
pp. eabh4276
Author(s):  
Jian Xie ◽  
Pengwei Zhang ◽  
Mac Crite ◽  
Christina V. Lindsay ◽  
Daniel DiMaio
Keyword(s):  
Capsid Protein ◽  
Protein Trafficking ◽  
Transmembrane Proteins ◽  
Cellular Protein ◽  
Human Papillomaviruses ◽  
Genetic Interactions ◽  
Cell Penetrating Peptide ◽  
Membrane Insertion ◽  
Associated Proteins ◽  
A Cell

Retromer, a cellular protein trafficking complex, sorts human papillomaviruses (HPVs) into the retrograde pathway for transport of HPV to the nucleus during virus entry. Here, we conducted a protein modulation screen to isolate four artificial transmembrane proteins called traptamers that inhibit different steps of HPV entry. By analyzing cells expressing pairs of traptamers, we ordered the trafficking steps during entry into a coherent pathway. One traptamer stimulates ubiquitination of the L2 capsid protein or associated proteins and diverts incoming virus to the lysosome, whereas the others act downstream by preventing sequential passage of the virus through retrograde compartments. Complex genetic interactions between traptamers revealed that a cell-penetrating peptide (CPP) on L2 mediates transient insertion of L2 into the endosome membrane, which is stabilized by retromer-L2 binding. These results define the retrograde entry route taken by HPV and show that retromer can play a role in CPP-mediated membrane insertion.

scholarly journals Phosphoserine acidic cluster motifs in the cytoplasmic domains of transmembrane proteins bind distinct basic regions on the μ subunits of clathrin adaptor protein complexes

2018 ◽  
Author(s):  
Rajendra Singh ◽  
Charlotte Stoneham ◽  
Christopher Lim ◽  
Xiaofei Jia ◽  
Javier Guenaga ◽  
...  
Keyword(s):  
Protein Trafficking ◽  
Transmembrane Proteins ◽  
Adaptor Protein ◽  
Cellular Protein ◽  
Membrane Lipid ◽  
Dependent Manner ◽  
Cytoplasmic Domains ◽  
Clathrin Adaptor ◽  
Hiv 1

AbstractProtein trafficking in the endosomal system involves the recognition of specific signals within the cytoplasmic domains (CDs) of transmembrane proteins by clathrin adaptors. One such signal is the phosphoserine acidic cluster (PSAC), the prototype of which is in the endoprotease Furin. How PSACs are recognized by clathrin adaptors has been controversial. We reported previously that HIV-1 Vpu, which modulates cellular immunoreceptors, contains a PSAC that binds to the µ subunits of clathrin adaptor protein (AP) complexes. Here, we show that the CD of Furin binds the µ subunits of AP-1 and AP-2 in a phosphorylation-dependent manner. Moreover, we identify a PSAC in a cytoplasmic loop of the cellular transmembrane Serinc3, an inhibitor of the infectivity of retroviruses. The two serines within the PSAC of Serinc3 are phosphorylated by casein kinase II and mediate interaction with the µ subunits in vitro. The sites of these serines vary among mammals in a manner consistent with host-pathogen conflict, yet the Serinc3-PSAC seems dispensible for anti-HIV activity and for counteraction by HIV-1 Nef. The CDs of Vpu, Furin, and the PSAC-containing loop of Serinc3 each bind the μ subunit of AP-2 (µ2) with similar affinities, but they appear to utilize different basic regions on µ2. The Serinc3 loop requires a region previously reported to bind the acidic plasma membrane lipid phosphatidylinositol-4,5-bisphosphate. These data suggest that the PSACs within different proteins recognize different basic regions on the µ surface, providing the potential to inhibit the activity of viral proteins without necessarily affecting cellular protein trafficking.

scholarly journals An ω-3, but Not an ω-6 Polyunsaturated Fatty Acid Decreases Membrane Dipole Potential and Stimulates Endo-Lysosomal Escape of Penetratin

2021 ◽  
Vol 9 ◽  
Author(s):  
Florina Zakany ◽  
Mate Szabo ◽  
Gyula Batta ◽  
Levente Kárpáti ◽  
István M. Mándity ◽  
...  
Keyword(s):  
Linolenic Acid ◽  
Measurement Techniques ◽  
Transmembrane Proteins ◽  
Living Cells ◽  
Cell Penetrating Peptide ◽  
Dipole Potential ◽  
Membrane Dipole Potential ◽  
Cell Penetrating ◽  
A Cell ◽  
Novel Method

Although the largely positive intramembrane dipole potential (DP) may substantially influence the function of transmembrane proteins, its investigation is deeply hampered by the lack of measurement techniques suitable for high-throughput examination of living cells. Here, we describe a novel emission ratiometric flow cytometry method based on F66, a 3-hydroxiflavon derivative, and demonstrate that 6-ketocholestanol, cholesterol and 7-dehydrocholesterol, saturated stearic acid (SA) and ω-6 γ-linolenic acid (GLA) increase, while ω-3 α-linolenic acid (ALA) decreases the DP. These changes do not correlate with alterations in cell viability or membrane fluidity. Pretreatment with ALA counteracts, while SA or GLA enhances cholesterol-induced DP elevations. Furthermore, ALA (but not SA or GLA) increases endo-lysosomal escape of penetratin, a cell-penetrating peptide. In summary, we have developed a novel method to measure DP in large quantities of individual living cells and propose ALA as a physiological DP lowering agent facilitating cytoplasmic entry of penetratin.

scholarly journals γ-Secretase promotes membrane insertion of the human papillomavirus L2 capsid protein during virus infection

2018 ◽  
Vol 217 (10) ◽  
pp. 3545-3559 ◽  
Author(s):  
Takamasa Inoue ◽  
Pengwei Zhang ◽  
Wei Zhang ◽  
Kylia Goodner-Bingham ◽  
Allison Dupzyk ◽  
...  
Keyword(s):  
Capsid Protein ◽  
Retrograde Transport ◽  
Hpv Infection ◽  
Human Papillomaviruses ◽  
Membrane Insertion ◽  
Human Pathogens ◽  
Transport Pathway ◽  
Chaperone Function ◽  
Endosomal Membranes

Despite their importance as human pathogens, entry of human papillomaviruses (HPVs) into cells is poorly understood. The transmembrane protease γ-secretase executes a crucial function during the early stages of HPV infection, but the role of γ-secretase in infection and the identity of its critical substrate are unknown. Here we demonstrate that γ-secretase harbors a previously uncharacterized chaperone function, promoting low pH–dependent insertion of the HPV L2 capsid protein into endosomal membranes. Upon membrane insertion, L2 recruits the cytosolic retromer, which enables the L2 viral genome complex to enter the retrograde transport pathway and traffic to the Golgi en route for infection. Although a small fraction of membrane-inserted L2 is also cleaved by γ-secretase, this proteolytic event appears dispensable for HPV infection. Our findings demonstrate that γ-secretase is endowed with an activity that can promote membrane insertion of L2, thereby targeting the virus to the productive infectious pathway.

scholarly journals Structural Analysis of Jumbo Coliphage phAPEC6

2020 ◽  
Vol 21 (9) ◽  
pp. 3119 ◽  
Author(s):  
Jeroen Wagemans ◽  
Jessica Tsonos ◽  
Dominique Holtappels ◽  
Kiandro Fortuna ◽  
Jean-Pierre Hernalsteens ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Capsid Protein ◽  
Tem Analysis ◽  
Host Interaction ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
Tail Sheath ◽  
Associated Proteins ◽  
Contractile Tail ◽  
Phage Capsid

The phAPEC6 genome encodes 551 predicted gene products, with the vast majority (83%) of unknown function. Of these, 62 have been identified as virion-associated proteins by mass spectrometry (ESI-MS/MS), including the major capsid protein (Gp225; present in 1620 copies), which shows a HK97 capsid protein-based fold. Cryo-electron microscopy experiments showed that the 350-kbp DNA molecule of Escherichia coli virus phAPEC6 is packaged in at least 15 concentric layers in the phage capsid. A capsid inner body rod is also present, measuring about 91 nm by 18 nm and oriented along the portal axis. In the phAPEC6 contractile tail, 25 hexameric stacked rings can be distinguished, built of the identified tail sheath protein (Gp277). Cryo-EM reconstruction reveals the base of the unique hairy fibers observed during an initial transmission electron microscopy (TEM) analysis. These very unusual filaments are ordered at three annular positions along the contractile sheath, as well as around the capsid, and may be involved in host interaction.

scholarly journals A Cell-Penetrating Peptide with a Guanidinylethyl Amine Structure Directed to Gene Delivery

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Makoto Oba ◽  
Takuma Kato ◽  
Kaori Furukawa ◽  
Masakazu Tanaka
Keyword(s):  
Gene Delivery ◽  
Cell Penetrating Peptide ◽  
Cell Penetrating ◽  
Amine Structure ◽  
A Cell

Syndesmos, a protein that interacts with the cytoplasmic domain of syndecan-4, mediates cell spreading and actin cytoskeletal organization

2000 ◽  
Vol 113 (2) ◽  
pp. 315-324 ◽  
Author(s):  
P.C. Baciu ◽  
S. Saoncella ◽  
S.H. Lee ◽  
F. Denhez ◽  
D. Leuthardt ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Focal Adhesions ◽  
Cell Spreading ◽  
Cytoplasmic Domain ◽  
Cellular Protein ◽  
Actin Stress Fiber ◽  
Independent Manner ◽  
Intracellular Proteins ◽  
Central Regions ◽  
A Cell

Syndecan-4 is a cell surface heparan sulfate proteoglycan which, in cooperation with integrins, transduces signals for the assembly of focal adhesions and actin stress fibers in cells plated on fibronectin. The regulation of these cellular events is proposed to occur, in part, through the interaction of the cytoplasmic domains of these transmembrane receptors with intracellular proteins. To identify potential intracellular proteins that interact with the cytoplasmic domain of syndecan-4, we carried out a yeast two-hybrid screen in which the cytoplasmic domain of syndecan-4 was used as bait. As a result of this screen, we have identified a novel cellular protein that interacts with the cytoplasmic domain of syndecan-4 but not with those of the other three syndecan family members. The interaction involves both the membrane proximal and variable central regions of the cytoplasmic domain. We have named this cDNA and encoded protein syndesmos. Syndesmos is ubiquitously expressed and can be myristylated. Consistent with its myristylation and syndecan-4 association, syndesmos colocalizes with syndecan-4 in the ventral plasma membranes of cells plated on fibronectin. When overexpressed in NIH 3T3 cells, syndesmos enhances cell spreading, actin stress fiber and focal contact formation in a serum-independent manner.

Pharmacokinetics, Biodistribution, Stability and Toxicity of a Cell-Penetrating Peptide−Morpholino Oligomer Conjugate

2007 ◽  
Vol 18 (4) ◽  
pp. 1325-1331 ◽  
Author(s):  
Adams Amantana ◽  
Hong M. Moulton ◽  
Melissa L. Cate ◽  
Muralimohan T. Reddy ◽  
Tom Whitehead ◽  
...  
Keyword(s):  
Cell Penetrating Peptide ◽  
Cell Penetrating ◽  
A Cell
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