In most non-excitable cells, calcium (Ca²⁺) release from the inositol 1,4,5-trisphosphate (InsP₃)-sensitive intracellular Ca²⁺ stores is coupled to Ca²⁺ influx through the plasma membrane Ca²⁺ channels whose molecular composition is poorly understood. Several members of mammalian TRP-related protein family have been implicated to both receptor- and store-operated Ca²⁺ influx. Here we investigated the role of the native transient receptor potential 3 (TRPC3) homologue in mediating the store- and receptor-operated calcium entry in A431 cells. We show that suppression of TRPC3 protein levels by small interfering RNA (siRNA), leads to significant reduction in store-operated calcium influx without affecting the receptor-operated calcium influx. With the single-channel analysis, we further demonstrate that reduction of TRPC3 levels results in suppression of specific subtype of store-operated calcium channels and activation of store-independent channels. Our data suggest that TRPC3 is required for the formation of functional store-operated channels in A431 cells.