Signal transduction wasn't exactly the first thing that came to mind when my mother told me that she had medullary thyroid cancer. Thoughts of not having my mother around when I finally got married or had my first baby were more immediate. Now that she's in remission, I've had the chance to marvel at how a mutation in a receptor known as c-Ret could cause the calcitonin-producing C cells of the thyroid to proliferate uncontrollably.1
Known as a receptor tyrosine kinase (RTK), membrane-bound c-Ret is the first player in one of the many signal transduction pathways of the C cells. In response to ligand binding, RTKs--such as the receptors for insulin, platelet-derived growth factor, and epidermal growth factor-- phosphorylate either themselves or nearby proteins to initiate a signaling cascade.2
Researchers now know that many diseases beyond cancer, including diabetes, heart disease, and asthma, ultimately stem from messaging systems gone awry. ...