Identification of the interleukin-3 receptor using an iodinatable, cleavable, photoreactive cross-linking agent

Murine interleukin-3 (mIL-3) is a lymphokine that stimulates the proliferation and differentiation of both pluripotent hemopoietic stem cells and their committed progeny. However, very little is known about the mechanism by which this growth factor elicits its effects on responsive cell populations. To gain insight into early events following mIL-3 receptor interaction, we initiated studies to isolate the receptor and study its properties. In this report, we demonstrate the use of a new iodinatable, cleavable, photoreactive cross-linking agent, sulfosuccinimidyl 2-(p-azidosalicylamido)-1,3'-dithiopropionate to identify the mIL-3 receptor. These studies reveal the mIL-3 receptor to be a single polypeptide chain with a molecular weight of 67 kDa and an isoelectric point of approximately 6.2.