Biochemical analysis suggests distinct functional roles for the BLAST-1 and BLAST-2 antigens.
The biochemical processing of the BLAST-1 and BLAST-2 activation antigens has been studied. Both are glycoproteins that derive from different precursors of the same apparent m.w. on SDS-PAGE. BLAST-1 is synthesized as a 43,000 m.w. light chain in association with a second heavier chain of 55,000 m.w. The light chain acquires sialylated O-linked glycans and is stably expressed at the cell surface with a half-life of 14 hr. BLAST-2 is also synthesized as a 43,000 m.w. precursor, but it acquires only unsialylated N-linked glycans. The mature glycoprotein is only expressed briefly at the cell surface (half-life of 1 to 2 hr), and is then shed into the culture supernatant as a soluble 33,000 m.w. derivative. The different fates of these molecules, one stably expressed at the cell surface and one shed, suggest disparate roles for these two antigens in B cell activation.
Thorley-Lawson
D A
DA
Swendeman
S L
SL
Edson
C M
CM
D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification*; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D008970:Molecular Weight; D011233:Precipitin Tests; D011498:Protein Precursors / Q000096:biosynthesis / Q000276:immunology / Q000302:isolation & purification; D011499:Protein Processing, Post-Translational
D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D006023:Glycoproteins; D011498:Protein Precursors