Interaction of cholesterol-crystallization-promoting proteins with vesicles.
In this study, the interaction of mucin and concanavalin A-binding proteins isolated from human bile with cholesterol/phospholipid vesicles was investigated. Using resonance energy transfer assays originally developed by Struck, Hoekstra and Pagano [(1981) Biochemistry 20, 4093-4099], no significant protein-induced fusion or aggregation of vesicles was demonstrated. Instead of fusion, these proteins induced destabilization of cholesterol/phospholipid vesicles, as monitored by release of entrapped carboxyfluorescein. A good correlation (rho = 0.81) was obtained between the extent of leakage and the nucleation-promoting activity of the concanavalin A-binding proteins. We conclude that aggregation or fusion of cholesterol/phospholipid vesicles is not an obligatory step in cholesterol crystallization. Biliary protein-induced crystallization seems to be preceded by vesicle disruption.
de Bruijn
M A
MA
Division of Gastrointestinal and Liver Diseases, Academic Medical Centre, Amsterdam, The Netherlands.
Goldhoorn
B G
BG
Zijlstra
A I
AI
Tytgat
G N
GN
Groen
A K
AK
D001646:Bile / Q000737:chemistry; D002352:Carrier Proteins / Q000494:pharmacology; D002784:Cholesterol / Q000737:chemistry* / Q000502:physiology*; D003460:Crystallization; D004337:Drug Carriers; D004735:Energy Transfer; D005452:Fluoresceins; D006801:Humans; D008081:Liposomes; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D009077:Mucins / Q000494:pharmacology*; D010743:Phospholipids / Q000737:chemistry* / Q000502:physiology*; D011952:Receptors, Concanavalin A / Q000378:metabolism*
D002352:Carrier Proteins; D004337:Drug Carriers; D005452:Fluoresceins; D008081:Liposomes; D008562:Membrane Glycoproteins; D009077:Mucins; D010743:Phospholipids; D011952:Receptors, Concanavalin A; C024098:6-carboxyfluorescein; D002784:Cholesterol