Intracellular retention of glycosylphosphatidyl inositol-linked proteins in caveolin-deficient cells

The relationship between glycosylphosphatidyl inositol (GPI)-linked proteins and caveolins remains controversial. Here, we derived fibroblasts from Cav-1 null mouse embryos to study the behavior of GPI-linked proteins in the absence of caveolins. These cells lack morphological caveolae, do not expre...

Celý popis

Uloženo v:
Podrobná bibliografie
Vydáno v:Molecular and cellular biology Ročník 22; číslo 11; s. 3905
Hlavní autoři: Sotgia, Federica, Razani, Babak, Bonuccelli, Gloria, Schubert, William, Battista, Michela, Lee, Hyangkyu, Capozza, Franco, Schubert, Ann Lane, Minetti, Carlo, Buckley, J Thomas, Lisanti, Michael P
Médium: Journal Article
Jazyk:angličtina
Vydáno: United States 01.06.2002
Témata:
3T3 Cells
Animals
Binding Sites
Biological Transport, Active
Caveolin 1
Caveolins - chemistry
Caveolins - deficiency
Caveolins - genetics
Caveolins - metabolism
Cell Compartmentation
CSK Tyrosine-Protein Kinase
Glycoproteins - metabolism
Glycosylphosphatidylinositols - metabolism
Intracellular Fluid - metabolism
Kidney Tubules - metabolism
Lung - metabolism
Membrane Microdomains - metabolism
Mice
Mice, Knockout
Muscle, Skeletal - metabolism
Palmitic Acid - metabolism
Protein-Tyrosine Kinases - metabolism
src-Family Kinases
Transfection
ISSN:0270-7306
On-line přístup:Zjistit podrobnosti o přístupu
Tagy: Přidat tag
Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!
Popis
Shrnutí:The relationship between glycosylphosphatidyl inositol (GPI)-linked proteins and caveolins remains controversial. Here, we derived fibroblasts from Cav-1 null mouse embryos to study the behavior of GPI-linked proteins in the absence of caveolins. These cells lack morphological caveolae, do not express caveolin-1, and show a approximately 95% down-regulation in caveolin-2 expression; these cells also do not express caveolin-3, a muscle-specific caveolin family member. As such, these caveolin-deficient cells represent an ideal tool to study the role of caveolins in GPI-linked protein sorting. We show that in Cav-1 null cells GPI-linked proteins are preferentially retained in an intracellular compartment that we identify as the Golgi complex. This intracellular pool of GPI-linked proteins is not degraded and remains associated with intracellular lipid rafts as judged by its Triton insolubility. In contrast, GPI-linked proteins are transported to the plasma membrane in wild-type cells, as expected. Furthermore, recombinant expression of caveolin-1 or caveolin-3, but not caveolin-2, in Cav-1 null cells complements this phenotype and restores the cell surface expression of GPI-linked proteins. This is perhaps surprising, as GPI-linked proteins are confined to the exoplasmic leaflet of the membrane, while caveolins are cytoplasmically oriented membrane proteins. As caveolin-1 normally undergoes palmitoylation on three cysteine residues (133, 143, and 156), we speculated that palmitoylation might mechanistically couple caveolin-1 to GPI-linked proteins. In support of this hypothesis, we show that palmitoylation of caveolin-1 on residues 143 and 156, but not residue 133, is required to restore cell surface expression of GPI-linked proteins in this complementation assay. We also show that another lipid raft-associated protein, c-Src, is retained intracellularly in Cav-1 null cells. Thus, Golgi-associated caveolins and caveola-like vesicles could represent part of the transport machinery that is necessary for efficiently moving lipid rafts and their associated proteins from the trans-Golgi to the plasma membrane. In further support of these findings, GPI-linked proteins were also retained intracellularly in tissue samples derived from Cav-1 null mice (i.e., lung endothelial and renal epithelial cells) and Cav-3 null mice (skeletal muscle fibers).
Bibliografie:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0270-7306
DOI:10.1128/MCB.22.11.3905-3926.2002