Objective        To express heterologously Na

+

-H

+

antiporter 2 that potentially benefits the differentiation and maturation of the osteoclast in Saccharomyces cerevisiae

directly mutate the conservative key amino acid

and identify its function in transporting Na

+

as a salt transporter.       Methods       In turn mutating was carried out to make one of the two Asp of the antiporter into Cys by mutation kit. After two different mutants were achieved

two gene yeast vector was constructed to express them simultaneously in Saccharomyces cerevisiae. The obtained vectors were electroporated into yeast. The express of the two antiporter mutants in the

strain was detected by Western blotting. Their interaction of the two mutants was observed by the growth curve of BW31a in high salty concentration medium.       Results       Several vectors which can be transformed into yeast was successfully constructed. Each vector expressed the Na

+

-H

+

antiporter 2 in the yeast after induction by galactose in the solid or liquid medium. The growth curve revealed that the two mutants interacted to partly rescue the ability of yeast growing into high salt concentration medium.       Conclusion       The D278 and D279 sites are the key point for Na

+

-H

+

antiporter 2

which transports sodium possibly through forming dimmer in cells to maintain their regular growth.