Enables cytokine activity. Predicted to be involved in several processes, including positive regulation of interleukin-5 production; positive regulation of mast cell activation; and positive regulation of receptor signaling pathway via STAT. Predicted to act upstream of or within inflammatory response. Predicted to be integral component of membrane. Predicted to be part of receptor complex. Predicted to be active in external side of plasma membrane. Orthologous to human CRLF2 (cytokine receptor like factor 2). [provided by Alliance of Genome Resources, Apr 2022]