Calcium-binding protein that interacts with rotavirus cell receptors once the initial attachment by VP4 has been achieved. Rotavirus attachment and entry into the host cell probably involves multiple sequential contacts between the outer capsid proteins VP4 and VP7, and the cell receptors. Following entry into the host cell, low intracellular or intravesicular Ca(2+) concentration probably causes the calcium-stabilized VP7 trimers to dissociate from the virion. This step is probably necessary for the membrane-disrupting entry step and the release of VP4, which is locked onto the virion by VP7. Homotrimer; disulfide-linked. 2 Ca(2+) ions bound at each subunit interface in the trimer hold the trimer together. Interacts with the intermediate capsid protein VP6. Interacts with the outer capsid protein VP5*. The outer layer contains 780 copies of VP7, grouped as 260 trimers. Immature double-layered particles assembled in the cytoplasm bud across the membrane of the endoplasmic reticulum, acquiring during this process a transient lipid membrane that is modified with the ER resident viral glycoproteins NSP4 and VP7; these enveloped particles also contain VP4. As the particles move towards the interior of the ER. cisternae, the transient lipid membrane and the non-structural protein NSP4 are lost, while the virus surface proteins VP4 and VP7 rearrange to form the outermost virus protein layer, yielding mature infectious triple-layered particles. Intramolecular disulfide bonds. N-glycosylated. The N-terminus is blocked possibly by pyroglutamic acid. Some rotavirus strains are neuraminidase-sensitive and require sialic acid to attach to the cell surface. Some rotavirus strains are integrin-dependent. Some rotavirus strains depend on ganglioside for their entry into the host cell. Hsp70 also seems to be involved in the entry of some strains. In group A rotaviruses, VP7 defines the G serotype. Belongs to the rotavirus VP7 family.