Lentil lectin enriched microsomes from the plasma membrane of the human B-lymphocyte cell line H2LCL carry a heavy load of type-1 porin.
Using an established biochemical approach, five subcellular fractions of human B lymphocytes were prepared by differential centrifugation. Crude membranes were passed over a lentil lectin column to enrich carbohydrate-coated cell surface microsomes. The lectin-bound fraction contained a high amount of plasma membrane-derived microsomes as indicated by cell surface markers. All subcellular fractions in Western blots proved to contain distinct but variable amounts of porin. There was a strong increase in porin content from crude membranes to plasma membrane-derived vesicles. The porin content of this fraction appeared to be higher than that of mitochondria. In the final step the plasma membrane-derived microsome fraction proved to be devoid of contamination by outer mitochondrial membranes, as revealed by antibodies against the established markers MAO B and Tom20 applied in Western blots. These data prove the extramitochondrial expression of human type-1 porin/ type-1 VDAC.
Eben-Brunnen
J
J
Max-Planck-Institute for Experimental Medicine, Department of Immunochemistry, Göttingen, Germany.
Reymann
S
S
Awni
L A
LA
Cole
T
T
Hellmann
T
T
Hellmann
K P
KP
Paetzold
G
G
Kleineke
J
J
Thinnes
F P
FP
Götz
H
H
Hilschmann
N
N
D001402:B-Lymphocytes / Q000378:metabolism*; D015153:Blotting, Western; D002451:Cell Compartmentation; D002461:Cell Line, Transformed; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D037102:Lectins / Q000008:administration & dosage*; D008861:Microsomes / Q000378:metabolism*; D037121:Plant Lectins; D018272:Porins / Q000378:metabolism*
D037102:Lectins; D037121:Plant Lectins; D018272:Porins; C033619:lentil lectin