ABSTRACT
The effect of small G-proteins of the Rho family on sodium current conducted by cardiac isoform NaV1.5 of voltage-gated sodium channels was studied in heterologous expression system, CHO-K1 cell line transfected with a plasmid containing the NaV1.5 gene. The influence of cotransfection with genes of wild-type, constitutively-active, and dominant-negative small G-proteins RhoA, Rac1, and Cdc2 on the parameters of sodium current and its noninactivating component (INa,late) was estimated. Among three studied small G-proteins, only RhoA (wild-type and constitutively-active type) strongly affected sodium current reducing its peak amplitude, but not the value of INa,late. Cotransfection with wild-type Rac1 resulted in a minor decrease in sodium current. Thus, small G-protein RhoA has potential capability for suppression of sodium current, although physiological relevance of this property has to be verified.
