Problem
Loss-of-function mutations in the parkin gene PARK 2 cause juvenile onset of parkinsonism, a disease characterized by brain function alterations that cause dystonia (involuntary muscle contraction) and hyperreflexia (twitching and spastic tendencies). Remarkably, similar mutations in PARK 2 also increase the risk for contracting leprosy, a disease caused by a type of soil bacteria (Mycobacterium leprae). Thus, loss of PARK 2 separately affects the brain (parkinsonism) and bacterial infection of the peripheral nerves (leprosy). Parkin is thus necessary to prevent such diseases. To treat such diseases, we need to better understand the function of parkin. With this objective in mind, discuss four other types of aspects of parkin - its sufficiency, location, timing, interactions - that are analyzed to better understand its role in cell and tissue function and how its absence can lead to disease.