Abstract: AIM To screen the proteins interacted with human ether-a-go-go-related gene(HERG) potassium channel and to study the modulatory effect of the interacting protein on this channel. METHODS ①The N-terminal fragment of HERG (aa 1-404) was PCR-amplified by using the human cDNA that encoded the HERG potassium channel as template, and the fragment was then cloned into the pGBKT7 to construct the bait plasmid pGBKT7-HERG-NT. ②The yeast two-hybrid technique was used to screen the human heart cDNA library. ③The open reading frame of four and half LIM domain(FHL2) gene was PCR-amplified and cloned into the pcDNA3.0. ④The HEK293 cells were transfected with pcDNA3.0-herg, and the cells were then screened with G418 to obtain the HEK293/HERG cells. The HEK293 cells were transfected with pcDNA3.0-FHL2 to obtain the HEK293/FHL2 cells and the HEK293/FHL2 cells were transfected with pcDNA3.0-herg. ⑤The patch-clamp technique was used to study the effect of the interacting protein on the HERG channel property. RESULTS ①Thirty-seven clones were selected by the yeast two-hybrid screen, one of which was FHL2. ②The patch clamp electrophysiological experiment showed that FHL2 increased the HERG current amplitude and accelerated the activation rate of the HERG potassium channel. CONCLUSION FHL2 interacts with the amino terminus of HERG and modulates the HERG potassium channel function.