VP1 is one of three simian virus 40 (SV40) capsid proteins. VP1 assembles into pentamers which have a central cavity that contains a copy of one of the other capsid proteins, VP2 or VP3. This complex is then imported into the cell nucleus. Here, 72 of the complexes assemble around the newly synthesised viral genome to form the icosahedral capsid.
Function:
Forms an icosahedral capsid with a T=7 symmetry and a 40 nm diameter. The capsid is composed of 72 pentamers linked to each other by disulfide bonds and associated with VP2 or VP3 proteins. Binds to N-glycolylneuraminic analog of the ganglioside GM1 on the cell surface to provide virion attachment to target cell. Once attached, the virion is internalized by caveolin-mediated endocytosis and traffics to the endoplasmic reticulum. Inside the endoplasmic reticulum, the protein folding machinery isomerizes VP1 interpentamer disulfide bonds, thereby triggering initial uncoating. Next, the virion uses the endoplasmic reticulum-associated degradation machinery to probably translocate in the cytosol before reaching the nucleus. Nuclear entry of the viral DNA involves the selective exposure and importin recognition of VP2/Vp3 nuclear localization signal. The assembly takes place in the cell nucleus. Encapsulates the genomic DNA and participates in rearranging nucleosomes around the viral DNA. The viral progenies exit the cells by lytic release.
Subunit:
Homomultimer; disulfide-linked. The virus capsid is composed of 72 icosahedral units, each one composed of five disulfide-linked copies of VP1. Interacts with agnoprotein. Interacts with minor capsid proteins VP2 and VP3. Interacts with host HSPA8; this interaction probably participates in virus assembly. Interacts with host SP1; this interaction enhances the efficiency of viral packaging.By similarity4 Publications.
Subcellular Location:
Virion. Host nucleus. Host endoplasmic reticulum. Note=Following host cell entry, the virion enters into the endoplasmic reticulum through a calveolar-dependent pathway. Then, viral DNA is translocated to the nucleus. Shortly after synthesis, a nuclear localization signal directs VP1 to the cell nucleus where virion assembly occurs.
Similarity:
Belongs to the polyomaviruses coat protein VP1 family.
SWISS:
P03087
Gene ID:
1849530
Database links:
SwissProt: P03087 Simian Virus 40
Gene ID: 1489530 Simian Virus 40
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