抄録
To overcome difficulties of conventional fusion with fluorescent/luminescent proteins, post-translational labeling methods using pairs of small genetically-encodable ‘tags’ and synthetic ‘probes’ targeting the tags have been widely studied in recent years. We have developed a quick tag-probe labeling method using a high-affinity heterodimeric coiled-coil formation between the E3 tag (EIAALEK)3 attached to the target protein and the Kn probe (KIAALKE)n (n = 3 or 4) labeled with a fluorophore. The labeling is cell-surface-specific and completed within 1 min, therefore suitable for monitoring oligomerization/internalization of membrane proteins on living cell surface. Taking advantage of easiness in multicolor labeling, the degree of internalization of the β2 adrenergic receptors following agonist stimulation was evaluated by ratiometric detection of pH decrease in endosomes.
