Inner capsid protein that self-assembles to form an icosahedral capsid with a T=2 symmetry, which consists of 120 copies of VP2, with channels at each of its five-fold vertices (PubMed:19036817). This capsid constitutes the innermost concentric layer of the viral mature particle (PubMed:19036817). It encapsidates the polymerase VP1, the capping enzyme VP3 and the genomic dsRNA, thereby defining the core. The innermost VP2 capsid and the intermediate VP6 capsid remain intact following cell entry to protect the dsRNA from degradation and to prevent unfavorable antiviral responses in the host cell during all the replication cycle of the virus. Nascent transcripts are transcribed within the structural confines of this double-layered particle (DLP) and are extruded through the channels formed by VP2 N-termini. VP2 is required for the replicase activity of VP1 polymerase. Probably recruits a copy of a VP1-VP3 complex, potentially along with a segment of plus-strand RNA, as a decamer of VP2 assembles (By similarity). May activate the autoinhibited VP1/RNA complex to coordinate packaging and genome replication (PubMed:19000820). Homodecamer; each decamer is made up of two conformers of VP2, called VP2A and VP2B (By similarity). Interacts with a VP1-VP3 complex (By similarity). Interacts with the intermediate capsid protein VP6 (PubMed:19036817). Interacts with NSP5 (By similarity). Interacts (via N-terminus) with NSP2 (By similarity). Inner capsid protein. Also found in spherical cytoplasmic structures, called virus factories, that appear early after infection and are the site of viral replication and packaging. The N-terminus binds RNA. It is necessary for encapsidation of VP1 and VP3. The N-termini of 10 VP2 molecules form a cylindrical hub underneath each 5-fold axis of the inner capsid. Sumoylated with SUMO1 and SUMO2. Sumoylation of viral proteins seems to have a positive role on viral replication. Belongs to the rotavirus VP2 family.