The central question behind the work of Tim Stearns's lab is how the centrosome and primary cilium control cell function and influence development, and how defects in these structures cause a remarkable range of human disease, ranging from cancer, polycystic kidney disease, and obesity, to neurocognitive defects including mental retardation, schizophrenia, and dyslexia.

The centrosome consists of a pair of centrioles and pericentriolar material and organizes the cytoplasmic microtubules of most animal cells. Most importantly, the mother centriole (the older of the two in the pair) nucleates the formation of a primary cilium in most cells in the body. First seen by cell biologists in the 1950's, the primary cilium was ignored for many years until a combination of human and model organism genetics revealed that it is a critical sensory organelle with functions in many important processes. Defects in primary cilium structure and function cause a set of human conditions, called ciliopathies, that share a set of phenotypes that reflect the importance of the cilium in signaling pathways.