protein dynamics inside live cells

Photobleaching can be used to reveal the dynamicsunderlying the steady-state distribution of a fluoro-phore. A fluorophore within a small region is madenon-fluorescent with very high intensity illumina-tion, and exchange between the bleached and un-bleached populations of fluorophore is then moni-tored. In most cases, the exact physical basis forbleaching is not known; the fluorophore is not de-stroyed but rather irreversibly, photochemically al-tered so that it no longer fluoresces