Binding to retinoblastoma pocket domain does not alter the inter-domain flexibility of the J domain of SV40 large T antigen.

Simian Virus 40 uses the large T antigen (Tag) to bind and inactivate retinoblastoma tumor suppressor proteins (Rb), which can result in cellular transformation. Tag is a modular protein with four domains connected by flexible linkers. The N-terminal J domain of Tag is necessary for Rb inactivation.

Calcium-dependent regulation of the voltage-gated sodium channel hH1: intrinsic and extrinsic sensors use a common molecular switch.

The function of the human cardiac voltage-gated sodium channel Na(V)1.5 (hH1) is regulated in part by binding of calcium to an EF hand in the C-terminal cytoplasmic domain. hH1 is also regulated via an extrinsic calcium-sensing pathway mediated by calmodulin (CaM) via binding to an IQ motif immediately adjacent to the EF-hand domain.