Functions as component of the ISW1A complex, which acts in remodeling the chromatin by catalyzing an ATP-dependent alteration in the structure of nucleosomal DNA. The ISW1A complex represses gene expression at initiation through specific positioning of a promoter proximal dinucleosome. Component of the ISW1A complex, which at least consists of ISW1 and IOC3. Present with 1770 molecules/cell in log phase SD medium.