title: Lysosomal biogenesis in lysosomal storage disorders.
abstract: Lysosomal biogenesis is an orchestration of the structural and functional elements of the lysosome to form an integrated organelle and involves the synthesis, targeting, functional residence, and turnover of the proteins that comprise the lysosome. We have investigated lysosomal biogenesis during the formation and dissipation of storage vacuoles in two model systems. One involves the formation of sucrosomes in normal skin fibroblasts and the other utilizes storage disorder-affected skin fibroblasts; both of these systems result in an increase in the size and the number of lysosomal vacuoles. Lysosomal proteins, beta-hexosaminidase, alpha-mannosidase, N-acetylgalactosamine-4-sulfatase, acid phosphatase, and the lysosome-associated membrane protein, LAMP-1, were shown to be elevated between 2- and 28-fold above normal during lysosomal storage. Levels of mRNA for the lysosome-associated membrane proteins LAMP-1 and LAMP-2, N-acetylgalactosamine-4-sulfatase, and the 46- and 300-kDa mannose-6-phosphate receptors were also elevated 2- to 8-fold. The up-regulation of protein and mRNA lagged 2-4 days behind the formation of lysosomal storage vacuoles. Correction of storage, in both systems, resulted in the rapid decline of the mRNA to basal levels, with a slower decrease in the levels of lysosomal proteins. Lysosomal biogenesis in storage disorders is shown to be a regulated process which is partially controlled at, or prior to, the level of mRNA. Although lysosomal proteins were differentially regulated, the coordination of these events in lysosomal biogenesis would suggest that a common mechanism(s) may be in operation.
authors.affiliation: Department of Chemical Pathology, Women's and Children's Hospital, North Adelaide, South Australia.
authors.forename: L E
authors.initials: LE
authors.lastname: Karageorgos
authors.forename: E L
authors.initials: EL
authors.lastname: Isaac
authors.forename: D A
authors.initials: DA
authors.lastname: Brooks
authors.forename: E M
authors.initials: EM
authors.lastname: Ravenscroft
authors.forename: R
authors.initials: R
authors.lastname: Davey
authors.forename: J J
authors.initials: JJ
authors.lastname: Hopwood
authors.forename: P J
authors.initials: PJ
authors.lastname: Meikle
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D016464:Lysosomal Storage Diseases / Q000378:metabolism*; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008854:Microscopy, Electron; D012333:RNA, Messenger / Q000378:metabolism; D012867:Skin / Q000166:cytology; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D013395:Sucrose