Binds as a monomer with high affinity to interleukin-13 (IL13), but not to interleukin-4 (IL4). The WSXWS motif appears to be necessary for proper protein folding and thereby efficient intracellular transport and cell-surface receptor binding. The box 1 motif is required for JAK interaction and/or activation. Belongs to the type I cytokine receptor family. Type 5 subfamily.