Regulation of thioredoxin reductase by calcium in Hermansky-Pudlak syndrome.
Cell cultures of keratinocytes, established from four Hermansky-Pudlak syndrome (HPS) homozygotes yielded low membrane-associated thioredoxin reductase activities compared with normal healthy adult controls. This low activity has been shown to be caused by a special sensitivity of the enzyme to calcium. 45Calcium has been used to compare the kinetics for the transport and bioaccumulation of this regulatory cation in keratinocyte cultures of a kindred with HPS (i.e., one HPS homozygote, one HPS obligate heterozygote, one normal family member, and healthy adult controls). The results show that both HPS-homozygous and -heterozygous cells bind more extracellular calcium than noncarriers of this genetic defect, and HPS homozygous cells appear to have a defective calcium transport system.
Schallreuter
K U
KU
Department of Dermatology, University of Hamburg, Federal Republic of Germany.
Pittelkow
M R
MR
D000042:Absorption; D000328:Adult; D000417:Albinism; D001692:Biological Transport; D001791:Blood Platelet Disorders; D002118:Calcium / Q000032:analysis / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D012871:Skin Diseases / Q000378:metabolism*; D013577:Syndrome; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism*
D009247:NADH, NADPH Oxidoreductases; D013880:Thioredoxin-Disulfide Reductase; D002118:Calcium