cotransporter

Cotransporters are a subcategory of transporters that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient and include antiporters and symporters. In general, cotransporters consist of two out of the three classes of integral membrane proteins known as transporters that move  molecules and ions across biomembranes.    Uniporters are also transporters but move only one type of molecule down its concentration gradient and are not classified as cotransporters.