title: In Cellulo Mapping of Subcellular Localized Bilirubin.
abstract: Bilirubin (BR) is a de novo synthesized metabolite of human cells. However, subcellular localization of BR in the different organelles of human cells has been largely unknown. Here, utilizing UnaG as a genetically encoded fluorescent BR sensor, we report the existence of relatively BR-enriched and BR-depleted microspaces in various cellular organelles of live cells. Our studies indicate that (i) the cytoplasmic facing membrane of the endoplasmic reticulum (ER) and the nucleus are relatively BR-enriched spaces and (ii) mitochondrial intermembrane space and the ER lumen are relatively BR-depleted spaces. Thus, we demonstrate a relationship between such asymmetrical BR distribution in the ER membrane and the BR metabolic pathway. Furthermore, our results suggest plausible BR-transport and BR-regulating machineries in other cellular compartments, including the nucleus and mitochondria.
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulju-gun, Ulsan, 44919, Republic of Korea.
authors.forename: Jong-Seok
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulju-gun, Ulsan, 44919, Republic of Korea.
authors.forename: Eunju
authors.initials: E
authors.lastname: Nam
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulju-gun, Ulsan, 44919, Republic of Korea.
authors.forename: Hye-Kyeong
authors.initials: HK
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulju-gun, Ulsan, 44919, Republic of Korea.
authors.forename: Mi Hee
authors.initials: MH
authors.lastname: Lim
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST) , Ulju-gun, Ulsan, 44919, Republic of Korea.
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Rhee
mesh_terms: D001663:Bilirubin / Q000378:metabolism; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D001663:Bilirubin