Abstract:  Modern microscopy provides opportunities for viewing all aspects of cell biology. It is feasible to image multiple proteins at once by fluorescence microscopy (FM), electron microscopy (EM), or correlative light and electron microscopy (CLEM). These multi-scale studies require protein labels that are versatile: bright organic fluorophores for FM, electron-dense nanoparticles for EM, and other novel reporters. With few options, most researchers rely on immunolabeling for nanoscale imaging, which has many drawbacks. Research in the Beatty Lab is focused on developing innovative and accessible strategies for analyzing cellular proteins across size scales and instrumentation. We developed Versatile Interacting Peptide (VIP) tags for this purpose. VIP tags consist of a heterodimeric coiled-coil between a genetically-encoded peptide tag and a reporter-conjugated “probe peptide”. Coiled-coils are a simple structural motif amenable to optimization by protein engineering. The dimerization specificity and affinity of VIP tags are dictated by the peptide sequence. To date, we have published three VIP tags: VIP Y/Z, VIPER, and miniVIPER. All three VIP tags enabled the selective labeling of a variety of cellular proteins and organelles. Importantly, this technology can be used to deliver a variety of biophysical reporters, including bright fluorophores (e.g., cyanines, BODIPY, xanthenes) and EM-compatible particles (e.g., gold or Qdots). VIP tags have been used in distinct applications, including pulse-chase labeling, observing endocytosis, and quantification of receptors in EM micrographs. This seminar will discuss protein labeling and include progress developing two new genetic tags: TinyVIPER and PunyVIPER

Originally published at chemistry.nd.edu.