scholarly journals A requirement for Potassium and Calcium Channels during the Endosomal Trafficking of Polyomavirus Virions

2019 ◽  
Author(s):  
Samuel J. Dobson ◽  
Jamel Mankouri ◽  
Adrian Whitehouse
Keyword(s):  
Ion Channels ◽  
Broad Spectrum ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Asymptomatic Infection ◽  
Endocytic Pathway ◽  
Endosomal Trafficking ◽  
Nuclear Entry ◽  
Novel Target

ABSTRACTFollowing internalisation viruses have to escape the endocytic pathway and deliver their genomes to initiate replication. Members of the Polyomaviridae transit through the endolysosomal network and through the endoplasmic reticulum (ER), from which heavily degraded capsids escape into the cytoplasm prior to nuclear entry. Acidification of endosomes and ER entry are essential in the lifecycle of polyomaviruses, however many mechanistic requirements are yet to be elucidated. Alteration of endocytic pH relies upon the activity of ion channels. Using two polyomaviruses with differing capsid architecture, namely Simian virus 40 (SV40) and Merkel cell polyomavirus (MCPyV), we firstly describe methods to rapidly quantify infection using an IncuCyte ZOOM instrument, prior to investigating the role of K+ and Ca2+ channels during early stages of infection. Broad spectrum inhibitors identified that MCPyV, but not SV40, is sensitive to K+ channel modulation. In contrast, both viruses are restricted by the broad spectrum Ca2+ channel inhibitor verapamil, however specific targeting of transient or long lasting Ca2+ channel subfamilies had no detrimental effect. Further investigation revealed that tetrandrine blockage of two-pore channels (TPCs), the activity of which is essential for endolysosomal-ER fusion, ablates infectivity of both MCPyV and SV40 by preventing disassembly of the capsid, which is required for the exposure of minor capsid protein nuclear signals necessary for nuclear transport. This study therefore identifies a novel target to restrict the entry of polyomaviruses.IMPORTANCEPolyomaviruses establish ubiquitous, asymptomatic infection in their host. However, in the immunocompromised these viruses can cause a range of potentially fatal diseases. Through the use of SV40 and MCPyV, two polyomaviruses with different capsid organisation, we have investigated the role of ion channels during infection. Here, we show that Ca2+ channel activity is essential for both polyomaviruses and that MCPyV is also sensitive to K+ channel blockage, highlighting new mechanistic requirements of ion channels during polyomavirus infection. In particular, tetrandrine blockage of endolysosomal-ER fusion is highlighted as an essential modulator of both SV40 and MCPyV. Given that the role of ion channels in disease have been well characterised, there is a large panel of clinically available therapeutics that could be repurposed to restrict persistent polyomavirus infection and may ultimately prevent polyomavirus-associated disease.

Role of specific simian virus 40 sequences in the nuclease-sensitive structure in viral chromatin

1985 ◽  
Vol 5 (1) ◽  
pp. 52-58
Author(s):  
R D Gerard ◽  
B A Montelone ◽  
C F Walter ◽  
J W Innis ◽  
W A Scott
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Origin Of Replication ◽  
Viral Origin ◽  
Deletion Mutations ◽  
Sensitive Region ◽  
Complete Independence ◽  
Sensitive Structure ◽  
Nuclease Sensitivity

A nuclease-sensitive region forms in chromatin containing a 273-base-pair (bp) segment of simian virus 40 DNA encompassing the viral origin of replication and early and late promoters. We have saturated this region with short deletion mutations and compared the nuclease sensitivity of each mutated segment to that of an unaltered segment elsewhere in the partially duplicated mutant. Although no single DNA segment is required for the formation of a nuclease-sensitive region, a deletion mutation (dl45) which disrupted both exact copies of the 21-bp repeats substantially reduced nuclease sensitivity. Deletion mutations limited to only one copy of the 21-bp repeats had little, if any, effect. A mutant (dl135) lacking all copies of the 21- and 72-bp repeats, while retaining the origin of replication and the TATA box, did not exhibit a nuclease-sensitive region. Mutants which showed reduced nuclease sensitivity had this effect throughout the nuclease-sensitive region, not just at the site of the deletion, indicating that although multiple determinants must be responsible for the nuclease-sensitive chromatin structure they do not function with complete independence. Mutant dl9, which lacks the late portion of the 72-bp segment, showed reduced accessibility to BglI, even though the BglI site is 146 bp away from the site of the deletion.

scholarly journals Role of Endosomes in Simian Virus 40 Entry and Infection

2011 ◽  
Vol 85 (9) ◽  
pp. 4198-4211 ◽  
Author(s):  
S. Engel ◽  
T. Heger ◽  
R. Mancini ◽  
F. Herzog ◽  
J. Kartenbeck ◽  
...  
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus

scholarly journals Human invasive trophoblasts transformed with simian virus 40 provide a new tool to study the role of PPAR  in cell invasion process

2003 ◽  
Vol 24 (8) ◽  
pp. 1325-1336 ◽  
Author(s):  
L. Pavan ◽  
A. Tarrade ◽  
A. Hermouet ◽  
C. Delouis ◽  
M. Titeux ◽  
...  
Keyword(s):  
Cell Invasion ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Invasion Process

Deletion mutants which affect the nuclease-sensitive site in simian virus 40 chromatin

1982 ◽  
Vol 2 (7) ◽  
pp. 782-788
Author(s):  
R D Gerard ◽  
M Woodworth-Gutai ◽  
W A Scott
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Deletion Mutants ◽  
Sequence Information ◽  
Base Pairs ◽  
Deletion Mutations ◽  
Sensitive Site ◽  
Late Side ◽  
Nuclease Sensitivity

A short segment of simian virus 40 (SV40) chromatin on the late side of the origin of replication is hypersensitive to nuclease cleavage. The role of DNA sequence information in this nuclease-sensitive feature was examined by constructing deletion mutations in this region. Deletions were introduced into the inserted segment of in(Or)-1411 (a viable, partially duplicated variant of SV40), and nuclease sensitivity of the inserted segment was compared with that of the unaltered sequences in their normal location in the viral genome. Extended deletions (118 to 161 base pairs) essentially abolished nuclease sensitivity within the inserted segment. Shorter deletions (21 to 52 base pairs) at separate locations retained the nuclease-sensitive feature. In some short-deletion mutants nuclease susceptibility was substantially reduced. We conclude that more than one genetic element in this region contributes to the organization of the nuclease-sensitive feature and that the SV40 72-base repeat is not, in itself, sufficient signal for this feature.

Activation of simian virus 40 promoter by HTLV-I Tax protein: role of NF-κB and CBP

2004 ◽  
Vol 318 (4) ◽  
pp. 1052-1056 ◽  
Author(s):  
Yulia Tabakin-Fix ◽  
Mahmoud Huleihel ◽  
Mordechai Aboud
Keyword(s):  
Simian Virus 40 ◽  
Simian Virus ◽  
Tax Protein

scholarly journals Clathrin- and caveolin-1–independent endocytosis

2005 ◽  
Vol 168 (3) ◽  
pp. 477-488 ◽  
Author(s):  
Eva-Maria Damm ◽  
Lucas Pelkmans ◽  
Jürgen Kartenbeck ◽  
Anna Mezzacasa ◽  
Teymuras Kurzchalia ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Knockout Mouse ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Endocytic Pathway ◽  
Host Cells ◽  
Human Hepatoma ◽  
Wild Type ◽  
Embryonic Fibroblasts ◽  
Caveolin 1

Simian Virus 40 (SV40) has been shown to enter host cells by caveolar endocytosis followed by transport via caveosomes to the endoplasmic reticulum (ER). Using a caveolin-1 (cav-1)–deficient cell line (human hepatoma 7) and embryonic fibroblasts from a cav-1 knockout mouse, we found that in the absence of caveolae, but also in wild-type embryonic fibroblasts, the virus exploits an alternative, cav-1–independent pathway. Internalization was rapid (t1/2 = 20 min) and cholesterol and tyrosine kinase dependent but independent of clathrin, dynamin II, and ARF6. The viruses were internalized in small, tight-fitting vesicles and transported to membrane-bounded, pH-neutral organelles similar to caveosomes but devoid of cav-1 and -2. The viruses were next transferred by microtubule-dependent vesicular transport to the ER, a step that was required for infectivity. Our results revealed the existence of a virus-activated endocytic pathway from the plasma membrane to the ER that involves neither clathrin nor caveolae and that can be activated also in the presence of cav-1.

scholarly journals SGTA-Dependent Regulation of Hsc70 Promotes Cytosol Entry of Simian Virus 40 from the Endoplasmic Reticulum

2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Allison Dupzyk ◽  
Jeffrey M. Williams ◽  
Parikshit Bagchi ◽  
Takamasa Inoue ◽  
Billy Tsai
Keyword(s):  
Endoplasmic Reticulum ◽  
Biological Membrane ◽  
Critical Role ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Membrane Penetration ◽  
Critical Function ◽  
Nonenveloped Virus ◽  
Er Membrane

ABSTRACT Membrane penetration by nonenveloped viruses remains enigmatic. In the case of the nonenveloped polyomavirus simian virus 40 (SV40), the virus penetrates the endoplasmic reticulum (ER) membrane to reach the cytosol and then traffics to the nucleus to cause infection. We previously demonstrated that the cytosolic Hsc70-SGTA-Hsp105 complex is tethered to the ER membrane, where Hsp105 and SGTA facilitate the extraction of SV40 from the ER and transport of the virus into the cytosol. We now find that Hsc70 also ejects SV40 from the ER into the cytosol in a step regulated by SGTA. Although SGTA's N-terminal domain, which mediates homodimerization and recruits cellular adaptors, is dispensable during ER-to-cytosol transport of SV40, this domain appears to exert an unexpected post-ER membrane translocation function during SV40 entry. Our study thus establishes a critical function of Hsc70 within the Hsc70-SGTA-Hsp105 complex in promoting SV40 ER-to-cytosol membrane penetration and unveils a role of SGTA in controlling this step. IMPORTANCE How a nonenveloped virus transports across a biological membrane to cause infection remains mysterious. One enigmatic step is whether host cytosolic components are co-opted to transport the viral particle into the cytosol. During ER-to-cytosol membrane transport of the nonenveloped polyomavirus SV40, a decisive infection step, a cytosolic complex composed of Hsc70-SGTA-Hsp105 was previously shown to associate with the ER membrane. SGTA and Hsp105 have been shown to extract SV40 from the ER and transport the virus into the cytosol. We demonstrate here a critical role of Hsc70 in SV40 ER-to-cytosol penetration and reveal how SGTA controls Hsc70 to impact this process.

scholarly journals Cell Penetration and Trafficking of Polyomavirus

2003 ◽  
Vol 77 (4) ◽  
pp. 2615-2622 ◽  
Author(s):  
Joanna M. Gilbert ◽  
Ilya G. Goldberg ◽  
Thomas L. Benjamin
Keyword(s):  
Actin Filaments ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Endocytic Pathway ◽  
Dynamic State ◽  
Cell Penetration ◽  
Stabilizing Agents ◽  
Virus Particles ◽  
Murine Polyomavirus ◽  
Microfilament System

ABSTRACT The murine polyomavirus (Py) enters mouse fibroblasts and kidney epithelial cells via an endocytic pathway that is caveola-independent (as well as clathrin-independent). In contrast, uptake of simian virus 40 into the same cells is dependent on caveola. Following the initial uptake of Py, both microtubules and microfilaments play roles in trafficking of the virus to the nucleus. Colcemid, which disrupts microtubules, inhibits the ability of Py to reach the nucleus and replicate. Paclitaxel, which stabilizes microtubules and prevents microtubule turnover, has no effect, indicating that intact but not dynamic microtubules are required for Py infectivity. Compounds that disrupt actin filaments enhance Py uptake while stabilization of actin filaments impedes Py infection. Virus particles are seen in association with actin in cells treated with microfilament-disrupting or filament-stabilizing agents at levels comparable to those in untreated cells, suggesting that a dynamic state of the microfilament system is important for Py infectivity.

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