Mouse skin from transgenic mice shows prominent expression of a protein called Fyn (brown color, left). Levels of Fyn drop dramatically in Fyn/Srcasm mice, which has increased levels of the protein Srcasm (center). Fyn levels remain prominent in Fyn/Srcasm-P mice, which express an inactive form of Srcasm (right).

Image Credit: Weijie Li, MD, PhD, University of Pennsylvania School of Medicine