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. Interacts with a N-linked glycoprotein containing sialic acids on the cell surface to provide virion attachment to target cell. Once attached, the virion is internalized by 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. In late phase of infection, neo-synthesized VP1 encapsulates replicated genomic DNA in the nucleus, and participates in rearranging nucleosomes around the viral DNA. Homomultimer; disulfide-linked. The virus capsid is composed of 72 icosahedral units, each one composed of five disulfide-linked copies of VP1. Interacts with minor capsid proteins VP2 and VP3. A DNA-binding domain overlapping a bipartite nuclear localization signal is present in the N-terminal region of the protein and is required for efficient virus formation. The intrinsically disordered C-terminal arm interacts with neighboring pentamers. The unstructured nature of this region allows to make different interactions depending on the structural context: pentamers present at the 12 icosahedral fivefold axes bind five pentamers, whereas pentamers present at the 60 icosahedral six-fold axes interact with six pentamers. Produced by alternative splicing of the late mRNA. Belongs to the polyomaviruses coat protein VP1 family.