title: Differences between OK and LLC-PK1 cells: cystine handling.
abstract: Cultured opossum kidney (OK) and porcine kidney (LLC-PK1) cells were compared for biochemical characteristics and cystine transport systems. The cell lines differ in amount of protein per cell, with OK cells having approximately one-half the amount found in LLC-PK1. Both cell lines contain 19 micrograms DNA/10(6) cells. As cells reach confluence, cystine uptake increases in OK and decreases in LLC-PK1 cells. Throughout the growth period, only lysine inhibits cystine uptake in OK, whereas glutamate is the inhibitor in LLC-PK1. The predominant site of cystine transport in OK cells is across the apical membrane, and the basolateral membrane is the corresponding site of transport in LLC-PK1 cells. Although the intracellular reduced glutathione pool is the same, the cysteine pool in OK cells is approximately one-fourth that found in LLC-PK1 cells. The ability of OK cells to reflect the shared cystine-dibasic amino acid transport system and LLC-PK1 to exhibit the cystine-glutamate antiporter system makes available two models for investigation of the development and structure of cystine transport systems.
authors.affiliation: Division of Biochemical Development and Molecular Diseases, Children's Hospital of Philadelphia, Pennsylvania.
authors.forename: B
authors.initials: B
authors.lastname: States
authors.forename: D
authors.initials: D
authors.lastname: Harris
authors.forename: S
authors.initials: S
authors.lastname: Segal
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002452:Cell Count; D002455:Cell Division; D002460:Cell Line / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D003553:Cystine / Q000378:metabolism*; D004247:DNA / Q000032:analysis; D020558:GTP Phosphohydrolases / Q000378:metabolism; D007700:Kinetics; D008854:Microscopy, Electron; D009893:Opossums; D010281:Parathyroid Hormone / Q000502:physiology; D011506:Proteins / Q000032:analysis; D013438:Sulfhydryl Compounds / Q000032:analysis; D013552:Swine; D014667:Vasopressins / Q000502:physiology
chemical_list: D010281:Parathyroid Hormone; D011506:Proteins; D013438:Sulfhydryl Compounds; D014667:Vasopressins; D003553:Cystine; D004247:DNA; D020558:GTP Phosphohydrolases