Enables cytokine activity; growth factor activity; and interleukin-3 receptor binding activity. Acts upstream of or within several processes, including cell surface receptor signaling pathway; monocyte differentiation; and regulation of phosphate metabolic process. Located in extracellular space. Is expressed in skin; stomach; thymus; and vascular system. Human ortholog(s) of this gene implicated in Graves' disease; asthma; and rheumatoid arthritis. Orthologous to human IL3 (interleukin 3). [provided by Alliance of Genome Resources, Apr 2022]