Functional analysis of four tetraspans, CD9, CD53, CD81, and CD82, suggests a common role in costimulation, cell adhesion, and migration: only CD9 upregulates HB-EGF activity.
Molecules of the tetraspan superfamily are engaged in multimolecular complexes containing other proteins such as beta 1 integrins and MHC antigens. Although their functions are not clear, they have been suggested to play a role in cell adhesion and migration, signal transduction, and costimulation. We have in this paper directly compared the functional properties of four tetraspans, CD9, CD53, CD81, and CD82. mAbs to any of these molecules were able to deliver a costimulatory signal for CD3-mediated activation of the T cell line Jurkat. CD82 mAbs were the most efficient in triggering this effect. Moreover, engagement of CD9, CD81, and CD82 induced the homotypic aggregation of the megakaryocytic cell line HEL, and inhibited the migration of this cell line. Similar results were obtained with the preB cell line NALM-6 using the CD9 and CD81 mAbs. The CD81 mAb 5A6 produced the strongest effects. Therefore, the tetraspans are recognized by mAbs which produce similar effects on the same cell lines. This is consistent with the tetraspans being included in large molecular complexes and possibly forming a tetraspan network (the tetraspan web). We also demonstrate that the tetraspans are likely to keep specific functional properties inside this network. Indeed, we have demonstrated that the human CD9 is able, like the monkey molecule, to upregulate the activity of the transmembrane precursor of heparin-binding EGF as a receptor for the diphtheria toxin when cotransfected in murine LM cells. Neither CD81, nor CD82 had such activity. By using chimeric CD9/CD81 molecules we demonstrate that this activity requires the second half of CD9, which contains the large extracellular loop, the fourth transmembrane region, and the last short cytoplasmic domain.
Lagaudrière-Gesbert
C
C
INSERM U283, Hôpital Cochin, Paris, France.
Le Naour
F
F
Lebel-Binay
S
S
Billard
M
M
Lemichez
E
E
Boquet
P
P
Boucheix
C
C
Conjeaud
H
H
Rubinstein
E
E
D000818:Animals; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D002465:Cell Movement / Q000276:immunology; D017931:DNA Primers / Q000235:genetics; D004167:Diphtheria Toxin / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007376:Interleukin-2 / Q000096:biosynthesis; D051861:Kangai-1 Protein; D007739:L Cells; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins; D051379:Mice; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D060265:Tetraspanin 25; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D014162:Transfection; D015854:Up-Regulation
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; C554894:CD53 protein, human; C554798:CD81 protein, human; C497688:CD82 protein, human; C554869:CD9 protein, human; C554895:Cd53 protein, mouse; C554799:Cd81 protein, mouse; C497689:Cd82 antigen, mouse; C554870:Cd9 protein, mouse; D017931:DNA Primers; D004167:Diphtheria Toxin; C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D007376:Interleukin-2; D051861:Kangai-1 Protein; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D060265:Tetraspanin 25; D060225:Tetraspanin 28; D060245:Tetraspanin 29; D004815:Epidermal Growth Factor; D006493:Heparin