About FGF-R4
The protein encoded by this gene is a tyrosine kinase and cell surface receptor for fibroblast growth factors. The encoded protein is involved in the regulation of several pathways, including cell proliferation, cell differentiation, cell migration, lipid metabolism, bile acid biosynthesis, vitamin D metabolism, glucose uptake, and phosphate homeostasis. This protein consists of an extracellular region, composed of three immunoglobulin-like domains, a single hydrophobic membrane-spanning segment, and a cytoplasmic tyrosine kinase domain. The extracellular portion interacts with fibroblast growth factors, setting in motion a cascade of downstream signals, ultimately influencing mitogenesis and differentiation. [provided by RefSeq, Aug 2017]

About PE
Phycoerythrin (PE, R-PE) is a red-emitting fluorescent protein-chromophore complex that can be excited the 488-nm blue, 532-nm green, or 561-nm yellow-green laser with increasing efficiency and captured with a 586/14 nm bandpass filter. PE has an excitation peak at 565 nm and an emission peak at 578 nm. PE is 240kD in size and has an extinction coefficient of ~2x10^6 which makes it one of the brightest fluorophores available and a potent donor upon which to build tandem fluorophores with longer Stoke's Shifts.