The preparation and in vivo applications of caged peptides and proteins.

Cellular behavior, such as mitosis and motility, are controlled by both when and where specific intracellular signaling pathways are activated in response to environmental cues. Analogous temporally and spatially controlled events occur throughout the lifetime of an organism (e.g. embryogenesis). Consequently, reagents that can be switched on (or off) at any time or at any place in a cell, a tissue, or a living animal, represent the means by which the biochemical basis of spatially and temporally sensitive biological behavior can be evaluated. This review summarizes recent advances in the design and synthesis of light-activated ('caged') peptides and proteins as well as the application of these caged reagents to unanswered questions in biology.