Co-localization of galectin-1 with GM1 ganglioside in the course of its clathrin- and raft-dependent endocytosis.
Mammalian galectin-1 (Gal-1), a beta-galactoside-binding lectin has a prominent role in regulating cell adhesion, cell growth and immune responses. Downregulation of these biological functions may occur via internalization of Gal-1. In the present study we have investigated the mechanism and possible mediator(s) of Gal-1 endocytosis. We show that internalization occurs at a temperature higher than 22 degrees C in an energy dependent fashion. After one hour incubation Gal-1 localizes in the Golgi system within the cells, and then disappears without accumulation in degradation compartments, such as lysosomes. Based on their strong intracellular co-localization, two glycoconjugates, GM1 ganglioside and CD7 are implicated in the sorting of internalized Gal-1 into Golgi. Other known Gal-1 binding glycoproteins on T cells (CD2, CD3, CD43 and CD45) do not cointernalize with the lectin. Internalization of Gal-1 depends on its lectin activity and follows dual pathways involving clathrin-coated vesicles and raft-dependent endocytosis.
Fajka-Boja
R
R
Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of the Hungarian Academy of Sciences, Temesvári krt. 62, 6726 Szeged, Hungary. roberta@brc.hu
Blaskó
A
A
Kovács-Sólyom
F
F
Szebeni
G J
GJ
Tóth
G K
GK
Monostori
E
E
D000818:Animals; D019011:Antigens, CD7 / Q000378:metabolism; D002460:Cell Line; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis; D005677:G(M1) Ganglioside / Q000378:metabolism*; D037483:Galectin 1 / Q000378:metabolism*; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D008024:Ligands; D021962:Membrane Microdomains / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors
D019011:Antigens, CD7; D002966:Clathrin; D037483:Galectin 1; D008024:Ligands; D005677:G(M1) Ganglioside