The combinatorial extension method reveals a sphingolipid binding domain on pancreatic bile salt-dependent lipase: role in secretion.
Structure similarity searches using a combinatorial extension approach revealed that a protein fold structurally related to the sphingolipid binding domain (SBD) of HIV-1 gp120 (V3 loop) is present on pancreatic bile salt-dependent lipase (BSDL). A synthetic peptide derived from the predicted V3-like domain of BSDL interacted with reconstituted monolayers of sphingolipids such as GalCer and GlcCer. Using Chinese hamster ovary cells stably transfected with the cDNA encoding the rat BSDL (CHO-3B clone) or pancreatic SOJ-6 cells expressing the human BSDL as models, we showed that the enzyme cofractionates with caveolin-1. The secretion of BSDL by CHO-3B cells was inhibited by permeable drugs affecting rafts structure (D609, PDMP, and filipin). Data suggest that the functional interaction between the BSDL SBD and lipid rafts is physiologically relevant and could be essential for sensing the BSDL folding prior to secretion. A tentative model accounting for the phosphorylation-induced dissociation of BSDL from rafts is presented.
Aubert-Jousset
Emeline
E
INSERM U-559, EA-3289, and IPHM, Faculté de Médecine, Timone, 27 Bld Jean Moulin, 13385 Marseille 05, France.
Garmy
Nicolas
N
Sbarra
Véronique
V
Fantini
Jacques
J
Sadoulet
Marie-Odile
MO
Lombardo
Dominique
D
D000595:Amino Acid Sequence; D000818:Animals; D001952:Bridged-Ring Compounds / Q000494:pharmacology; D016466:CHO Cells; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D005372:Filipin / Q000494:pharmacology; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D021962:Membrane Microdomains / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009025:Morpholines / Q000494:pharmacology; D009636:Norbornanes; D010766:Phosphorylation / Q000187:drug effects; D017510:Protein Folding; D051381:Rats; D013107:Sphingolipids / Q000737:chemistry*; D002787:Sterol Esterase / Q000235:genetics / Q000378:metabolism*; D013859:Thiocarbamates; D013871:Thiones / Q000494:pharmacology
D001952:Bridged-Ring Compounds; C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D015699:HIV Envelope Protein gp120; D009025:Morpholines; D009636:Norbornanes; D013107:Sphingolipids; D013859:Thiocarbamates; D013871:Thiones; C046498:tricyclodecane-9-yl-xanthogenate; C033110:RV 538; D005372:Filipin; C054784:bile salt-stimulated lipase; D002787:Sterol Esterase