CD38 molecule: structural and biochemical analysis on human T lymphocytes, thymocytes, and plasma cells.
The structure of the CD38 molecule has been evaluated by one- and two-dimensional gel analysis and by enzymatic digestions. The source of the Ag was mainly membrane preparations obtained from MLC cells, from normal thymocytes, and from the plasmocytoma line LP-1. Membranes were solubilized in NP-40 and the extracts fractionated by immunoaffinity chromatography [using a specific anti-CD38 antibody (A10 mAb) covalently linked to Sepharose protein A]. The purified Ag migrated as a single chain of Mr = 45,000 not associated with beta 2-microglobulin. Two-dimensional IEF gel electrophoresis revealed five spots (isoelectric point (pI) range: 6.5 to 6.9). After neuraminidase treatment, the mobility of the five polypeptides shifted to a more basic pI. Endoglycosidase-H treatment reduced the Mr of CD38 by 20%, revealing a broader band centered at Mr = 36,000. Treatment of CD38 molecule with V8 Staphylococcus aureus protease yielded a single dominant band at Mr = 38,000 which was still reactive with A10 mAb. The CD38 molecular was trypsin-resistant in both denatured or native conditions. These results clearly show the glycoprotein nature of CD38 molecule, which includes 2 to 4 N-linked oligosaccharide chains containing sialic acid residues. Furthermore, the present data indicate that the CD38 molecule does not display an apparent biochemical polymorphism among the different CD38+ cells or lines.
Alessio
M
M
Dipartimento di Genetica, Biologia e Chimica Medica, Università di Torino, Italy.
Roggero
S
S
Funaro
A
A
De Monte
L B
LB
Peruzzi
L
L
Geuna
M
M
Malavasi
F
F
D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000032:analysis*; D000943:Antigens, Differentiation / Q000032:analysis* / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis; D006031:Glycosylation; D006801:Humans; D007525:Isoelectric Focusing; D008214:Lymphocytes / Q000276:immunology*; D008562:Membrane Glycoproteins; D051379:Mice; D010447:Peptide Hydrolases / Q000494:pharmacology; D010449:Peptide Mapping; D010950:Plasma Cells / Q000276:immunology*; D011233:Precipitin Tests; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000943:Antigens, Differentiation; D000939:Epitopes; D008562:Membrane Glycoproteins; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; C498155:Cd38 protein, mouse; D051997:ADP-ribosyl Cyclase 1; D010447:Peptide Hydrolases