POLG_HCVE0
ID POLG_HCVE0 Reviewed; 138 AA.
AC P27953;
DT 01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT 01-AUG-1992, sequence version 1.
DT 25-MAY-2022, entry version 92.
DE RecName: Full=Genome polyprotein;
DE Contains:
DE RecName: Full=Envelope glycoprotein E1;
DE AltName: Full=gp32;
DE AltName: Full=gp35;
DE Contains:
DE RecName: Full=Envelope glycoprotein E2;
DE AltName: Full=NS1;
DE AltName: Full=gp68;
DE AltName: Full=gp70;
DE Flags: Fragment;
OS Hepatitis C virus (isolate EC10) (HCV).
OC Viruses; Riboviria; Orthornavirae; Kitrinoviricota; Flasuviricetes;
OC Amarillovirales; Flaviviridae; Hepacivirus.
OX NCBI_TaxID=11106;
OH NCBI_TaxID=9606; Homo sapiens (Human).
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX PubMed=1846505; DOI=10.1016/0042-6822(91)90104-j;
RA Weiner A.J., Brauer M.J., Rosenblatt J., Richman K.H., Tung J.,
RA Crawford K., Bonino F., Saracco G., Choo Q.-L., Houghton M., Han J.H.;
RT "Variable and hypervariable domains are found in the regions of HCV
RT corresponding to the flavivirus envelope and NS1 proteins and the
RT pestivirus envelope glycoproteins.";
RL Virology 180:842-848(1991).
RN [2]
RP REVIEW.
RX PubMed=10718937; DOI=10.1046/j.1365-2893.2000.00201.x;
RA McLauchlan J.;
RT "Properties of the hepatitis C virus core protein: a structural protein
RT that modulates cellular processes.";
RL J. Viral Hepat. 7:2-14(2000).
RN [3]
RP REVIEW.
RX PubMed=14752815; DOI=10.1002/hep.20032;
RA Penin F., Dubuisson J., Rey F.A., Moradpour D., Pawlotsky J.-M.;
RT "Structural biology of hepatitis C virus.";
RL Hepatology 39:5-19(2004).
CC -!- FUNCTION: [Envelope glycoprotein E1]: Forms a heterodimer with envelope
CC glycoprotein E2, which mediates virus attachment to the host cell,
CC virion internalization through clathrin-dependent endocytosis and
CC fusion with host membrane (By similarity). Fusion with the host cell is
CC most likely mediated by both E1 and E2, through conformational
CC rearrangements of the heterodimer required for fusion rather than a
CC classical class II fusion mechanism (By similarity). E1/E2 heterodimer
CC binds host apolipoproteins such as APOB and ApoE thereby forming a
CC lipo-viro-particle (LVP) (By similarity). APOE associated to the LVP
CC allows the initial virus attachment to cell surface receptors such as
CC the heparan sulfate proteoglycans (HSPGs), syndecan-1 (SDC1), syndecan-
CC 1 (SDC2), the low-density lipoprotein receptor (LDLR) and scavenger
CC receptor class B type I (SCARB1) (By similarity). The cholesterol
CC transfer activity of SCARB1 allows E2 exposure and binding of E2 to
CC SCARB1 and the tetraspanin CD81 (By similarity). E1/E2 heterodimer
CC binding on CD81 activates the epithelial growth factor receptor (EGFR)
CC signaling pathway (By similarity). Diffusion of the complex E1-E2-EGFR-
CC SCARB1-CD81 to the cell lateral membrane allows further interaction
CC with Claudin 1 (CLDN1) and occludin (OCLN) to finally trigger HCV entry
CC (By similarity). {ECO:0000250|UniProtKB:P27958}.
CC -!- FUNCTION: [Envelope glycoprotein E2]: Forms a heterodimer with envelope
CC glycoprotein E1, which mediates virus attachment to the host cell,
CC virion internalization through clathrin-dependent endocytosis and
CC fusion with host membrane (By similarity). Fusion with the host cell is
CC most likely mediated by both E1 and E2, through conformational
CC rearrangements of the heterodimer required for fusion rather than a
CC classical class II fusion mechanism (By similarity). The interaction
CC between envelope glycoprotein E2 and host apolipoprotein E/APOE allows
CC the proper assembly, maturation and infectivity of the viral particles
CC (By similarity). This interaction is probably promoted via the up-
CC regulation of cellular autophagy by the virus (By similarity). E1/E2
CC heterodimer binds host apolipoproteins such as APOB and APOE thereby
CC forming a lipo-viro-particle (LVP) (By similarity). APOE associated to
CC the LVP allows the initial virus attachment to cell surface receptors
CC such as the heparan sulfate proteoglycans (HSPGs), syndecan-1 (SDC1),
CC syndecan-1 (SDC2), the low-density lipoprotein receptor (LDLR) and
CC scavenger receptor class B type I (SCARB1) (By similarity). The
CC cholesterol transfer activity of SCARB1 allows E2 exposure and binding
CC of E2 to SCARB1 and the tetraspanin CD81 (By similarity). E1/E2
CC heterodimer binding on CD81 activates the epithelial growth factor
CC receptor (EGFR) signaling pathway (By similarity). Diffusion of the
CC complex E1-E2-EGFR-SCARB1-CD81 to the cell lateral membrane allows
CC further interaction with Claudin 1 (CLDN1) and occludin (OCLN) to
CC finally trigger HCV entry (By similarity). Inhibits host EIF2AK2/PKR
CC activation, preventing the establishment of an antiviral state (By
CC similarity). Viral ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which
CC are respectively found on dendritic cells (DCs), and on liver
CC sinusoidal endothelial cells and macrophage-like cells of lymph node
CC sinuses (By similarity). These interactions allow the capture of
CC circulating HCV particles by these cells and subsequent facilitated
CC transmission to permissive cells such as hepatocytes and lymphocyte
CC subpopulations (By similarity). {ECO:0000250|UniProtKB:P26664,
CC ECO:0000250|UniProtKB:P27958}.
CC -!- SUBUNIT: [Envelope glycoprotein E1]: Forms a heterodimer with envelope
CC glycoprotein E2 (By similarity). Interacts with mature core protein (By
CC similarity). Interacts with protease NS2 (By similarity). The
CC heterodimer E1/E2 interacts with host CLDN1; this interaction plays a
CC role in viral entry into host cell (By similarity). Interacts with host
CC SPSB2 (via C-terminus) (By similarity). Part of the viral assembly
CC initiation complex composed of NS2, E1, E2, NS3, NS4A, NS5A and the
CC mature core protein (By similarity). {ECO:0000250|UniProtKB:P27958,
CC ECO:0000250|UniProtKB:Q99IB8}.
CC -!- SUBUNIT: [Envelope glycoprotein E2]: Forms a heterodimer with envelope
CC glycoprotein E1 (By similarity). Interacts with host CD81 and SCARB1
CC receptors; these interactions play a role in viral entry into host cell
CC (By similarity). Interacts with host EIF2AK2/PKR; this interaction
CC inhibits EIF2AK2 and probably allows the virus to evade the innate
CC immune response (By similarity). Interacts with host CD209/DC-SIGN and
CC CLEC4M/DC-SIGNR (By similarity). Interact with host SPCS1; this
CC interaction is essential for viral particle assembly (By similarity).
CC Interacts with protease NS2 (By similarity). The heterodimer E1/E2
CC interacts with host CLDN1; this interaction plays a role in viral entry
CC into host cell (By similarity). Part of the viral assembly initiation
CC complex composed of NS2, E1, E2, NS3, NS4A, NS5A and the mature core
CC protein (By similarity). {ECO:0000250|UniProtKB:P27958,
CC ECO:0000250|UniProtKB:Q99IB8}.
CC -!- SUBCELLULAR LOCATION: [Envelope glycoprotein E1]: Virion membrane
CC {ECO:0000305}; Single-pass type I membrane protein {ECO:0000305}. Host
CC endoplasmic reticulum membrane; Single-pass type I membrane protein
CC {ECO:0000250|UniProtKB:P27958}. Note=The C-terminal transmembrane
CC domain acts as a signal sequence and forms a hairpin structure before
CC cleavage by host signal peptidase (By similarity). After cleavage, the
CC membrane sequence is retained at the C-terminus of the protein, serving
CC as ER membrane anchor (By similarity). A reorientation of the second
CC hydrophobic stretch occurs after cleavage producing a single reoriented
CC transmembrane domain (By similarity). These events explain the final
CC topology of the protein (By similarity).
CC {ECO:0000250|UniProtKB:P27958}.
CC -!- SUBCELLULAR LOCATION: [Envelope glycoprotein E2]: Virion membrane
CC {ECO:0000305}; Single-pass type I membrane protein {ECO:0000305}. Host
CC endoplasmic reticulum membrane; Single-pass type I membrane protein
CC {ECO:0000250|UniProtKB:P27958}. Host lipid droplet
CC {ECO:0000250|UniProtKB:Q9WMX2}. Note=The C-terminal transmembrane
CC domain acts as a signal sequence and forms a hairpin structure before
CC cleavage by host signal peptidase (By similarity). After cleavage, the
CC membrane sequence is retained at the C-terminus of the protein, serving
CC as ER membrane anchor (By similarity). A reorientation of the second
CC hydrophobic stretch occurs after cleavage producing a single reoriented
CC transmembrane domain (By similarity). These events explain the final
CC topology of the protein (By similarity).
CC {ECO:0000250|UniProtKB:P27958}.
CC -!- DOMAIN: [Envelope glycoprotein E1]: The transmembrane regions of
CC envelope E1 and E2 glycoproteins are involved in heterodimer formation,
CC ER localization, and assembly of these proteins.
CC {ECO:0000250|UniProtKB:P27958}.
CC -!- DOMAIN: [Envelope glycoprotein E2]: The transmembrane regions of
CC envelope E1 and E2 glycoproteins are involved in heterodimer formation,
CC ER localization, and assembly of these proteins (By similarity).
CC Envelope E2 glycoprotein contain two highly variable regions called
CC hypervariable region 1 and 2 (HVR1 and HVR2) (By similarity). E2 also
CC contain two segments involved in CD81-binding (By similarity). HVR1 is
CC implicated in the SCARB1-mediated cell entry and probably acts as a
CC regulator of the association of particles with lipids (By similarity).
CC {ECO:0000250|UniProtKB:P26663, ECO:0000250|UniProtKB:P27958}.
CC -!- PTM: [Genome polyprotein]: Specific enzymatic cleavages in vivo yield
CC mature proteins (By similarity). The structural proteins, core, E1, E2
CC and p7 are produced by proteolytic processing by host signal peptidases
CC (By similarity). The core protein precursor is synthesized as a 23 kDa,
CC which is retained in the ER membrane through the hydrophobic signal
CC peptide (By similarity). Cleavage by the signal peptidase releases the
CC 21 kDa mature core protein (By similarity). The cleavage of the core
CC protein precursor occurs between aminoacids 176 and 188 but the exact
CC cleavage site is not known (By similarity). Some degraded forms of the
CC core protein appear as well during the course of infection (By
CC similarity). The other proteins (p7, NS2, NS3, NS4A, NS4B, NS5A and
CC NS5B) are cleaved by the viral proteases (By similarity).
CC Autoprocessing between NS2 and NS3 is mediated by the NS2 cysteine
CC protease catalytic domain and regulated by the NS3 N-terminal domain
CC (By similarity). {ECO:0000250|UniProtKB:P26664,
CC ECO:0000250|UniProtKB:P27958}.
CC -!- PTM: [Envelope glycoprotein E1]: Highly N-glycosylated.
CC {ECO:0000250|UniProtKB:P27958}.
CC -!- PTM: [Envelope glycoprotein E2]: Highly N-glycosylated.
CC {ECO:0000250|UniProtKB:P27958}.
CC -!- MISCELLANEOUS: Viral particle assembly takes place at the surface of
CC ER-derived membranes in close proximity to lipid droplets. NS2
CC associates with E1/E2 glycoproteins, NS3 and NS5A, which interacts with
CC the viral RNA and core protein to promote genome encapsidation. The
CC nucleocapsid buds at the ER membrane where E1/E2 glycoproteins are
CC anchored and afterward associate with nascent lipid droplet to acquire
CC APOE and APOC. Secretion of viral particles is probably regulated by
CC viroporin p7. {ECO:0000305}.
CC -!- SIMILARITY: Belongs to the hepacivirus polyprotein family.
CC {ECO:0000305}.
CC -!- WEB RESOURCE: Name=Virus Pathogen Resource;
CC URL="https://www.viprbrc.org/brc/home.spg?decorator=flavi_hcv";
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DR EMBL; X53136; CAA37296.1; -; Genomic_RNA.
DR BMRB; P27953; -.
DR SMR; P27953; -.
DR euHCVdb; X53136; -.
DR GO; GO:0044167; C:host cell endoplasmic reticulum membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0044186; C:host cell lipid droplet; IEA:UniProtKB-SubCell.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0019031; C:viral envelope; IEA:UniProtKB-KW.
DR GO; GO:0055036; C:virion membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0075512; P:clathrin-dependent endocytosis of virus by host cell; IEA:UniProtKB-KW.
DR GO; GO:0039654; P:fusion of virus membrane with host endosome membrane; IEA:UniProtKB-KW.
DR GO; GO:0019062; P:virion attachment to host cell; IEA:UniProtKB-KW.
DR InterPro; IPR002519; HCV_Env.
DR InterPro; IPR002531; HCV_NS1.
DR Pfam; PF01539; HCV_env; 1.
DR Pfam; PF01560; HCV_NS1; 1.
PE 3: Inferred from homology;
KW Clathrin-mediated endocytosis of virus by host;
KW Fusion of virus membrane with host endosomal membrane;
KW Fusion of virus membrane with host membrane; Glycoprotein;
KW Host endoplasmic reticulum; Host lipid droplet; Host membrane;
KW Host-virus interaction; Membrane; Transmembrane; Transmembrane helix;
KW Viral attachment to host cell; Viral envelope protein;
KW Viral penetration into host cytoplasm; Virion; Virus endocytosis by host;
KW Virus entry into host cell.
FT CHAIN <1..>138
FT /note="Genome polyprotein"
FT /id="PRO_0000450898"
FT CHAIN <1..84
FT /note="Envelope glycoprotein E1"
FT /id="PRO_0000037553"
FT CHAIN 85..>138
FT /note="Envelope glycoprotein E2"
FT /id="PRO_0000037554"
FT TOPO_DOM <1..59
FT /note="Lumenal"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT TRANSMEM 60..80
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT TOPO_DOM 81..>138
FT /note="Lumenal"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT REGION 85..111
FT /note="HVR1"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT SITE 84..85
FT /note="Cleavage; by host signal peptidase"
FT /evidence="ECO:0000250|UniProtKB:P26662"
FT CARBOHYD 6
FT /note="N-linked (GlcNAc...) asparagine; by host"
FT /evidence="ECO:0000255"
FT CARBOHYD 118
FT /note="N-linked (GlcNAc...) (high mannose) asparagine; by
FT host"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT CARBOHYD 124
FT /note="N-linked (GlcNAc...) (high mannose) asparagine; by
FT host"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT CARBOHYD 131
FT /note="N-linked (GlcNAc...) (high mannose) asparagine; by
FT host"
FT /evidence="ECO:0000250|UniProtKB:P27958"
FT NON_TER 1
FT NON_TER 138
SQ SEQUENCE 138 AA; 14781 MW; CD3F0A962DEAB1AD CRC64;
TTQGCNCSIY PGHITGHRMA WDMMMNWSPT TALVVAQLLR IPQAILDMIA GAHWGVLAGI
AYFSMVGNWA KVLAVLLLFA GVDAETHVTG GIAAKTTASL TGLFNLGAKQ NIQLINTNGS
WHINRTALNC NDSLNTGW
