VLPs induce a multicomponent intracellular calcium rise. The scheme summarizes the hypothetic mechanisms by which VLPs increase intracellular calcium concentration. Inset: Representative multicomponent effect of VLPs on intracellular calcium concentration in Fura-2 loaded isolated insect neuron cell body using the calcium imaging ratiometric method (C. Deshayes, unpublished data). VDCC, voltage-dependent calcium channel; TRP, transient receptor potential channel; SOCE, store-operated calcium entry; NCX, sodium–calcium exchanger; RYR, ryanodine receptor; IP3R, inositol triphosphate receptor; ER, endoplasmic reticulum.