Cell surface receptor for IL3 expressed on hematopoietic progenitor cells, monocytes and B-lymphocytes that controls the production and differentiation of hematopoietic progenitor cells into lineage-restricted cells (By similarity). Ligand stimulation rapidly induces hetrodimerization with IL3RB, phosphorylation and enzyme activity of effector proteins such as JAK2 and PI3K that play a role in signaling cell proliferation and differentiation (PubMed:10477686). Activation of JAK2 leads to STAT5-mediated transcriptional program (PubMed:10376805). Interacts with IL3. Heterodimer of an alpha and a beta subunit (PubMed:10477686). The beta subunit is common to the IL3, IL5 and GM-CSF receptors. Expressed on the cell surface. Mostly distributed inside the cells, except in the nuclei and is not transported to the cell surface. 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.