title: CD38 is associated with lipid rafts and upon receptor stimulation leads to Akt/protein kinase B and Erk activation in the absence of the CD3-zeta immune receptor tyrosine-based activation motifs.
abstract: T lymphocytes can be activated via the T cell receptor (TCR) or by triggering through a number of other cell surface structures, including the CD38 co-receptor molecule. Here, we show that in TCR+ T cells that express a CD3-zeta lacking the cytoplasmic domain, cross-linking with CD38- or CD3-specific monoclonal antibodies induces tyrosine phosphorylation of CD3-epsilon, zeta-associated protein-70, linker for activation of T cells, and Shc. Moreover, in these cells, anti-CD38 or anti-CD3 stimulation leads to protein kinase B/Akt and Erk activation, suggesting that the CD3-zeta-immunoreceptor tyrosine-based activation motifs are not required for CD38 signaling in T cells. Interestingly, in unstimulated T cells, lipid rafts are highly enriched in CD38, including the T cells lacking the cytoplasmic tail of CD3-zeta. Moreover, CD38 clustering by extensive cross-linking with an anti-CD38 monoclonal antibody and a secondary antibody leads to an increased resistance of CD38 to detergent solubilization, suggesting that CD38 is constitutively associated with membrane rafts. Consistent with this, cholesterol depletion with methyl-beta-cyclodextrin substantially reduces CD38-mediated Akt activation while enhancing CD38-mediated Erk activation. CD38/raft association may improve the signaling capabilities of CD38 via formation of protein/lipid domains to which signaling-competent molecules, such as immunoreceptor tyrosine-based activation motif-bearing CD3 molecules and protein-tyrosine kinases, are recruited.
authors.affiliation: Hospital Universitario San Cecilio, Granada 18012, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Zubiaur
authors.forename: Olga
authors.initials: O
authors.lastname: Fernández
authors.forename: Enza
authors.initials: E
authors.lastname: Ferrero
authors.forename: Javier
authors.initials: J
authors.lastname: Salmerón
authors.forename: Bernard
authors.initials: B
authors.lastname: Malissen
authors.forename: Fabio
authors.initials: F
authors.lastname: Malavasi
authors.forename: Jaime
authors.initials: J
authors.lastname: Sancho
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000502:physiology*; D017252:CD3 Complex / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology; D002460:Cell Line; D002784:Cholesterol / Q000502:physiology; D004789:Enzyme Activation; D008562:Membrane Glycoproteins; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000502:physiology*; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009244:NAD+ Nucleosidase / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000502:physiology; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase
chemical_list: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D015703:Antigens, CD; D000943:Antigens, Differentiation; D017252:CD3 Complex; D002352:Carrier Proteins; D002784:Cholesterol; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D020928:Mitogen-Activated Protein Kinases; D009244:NAD+ Nucleosidase; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011948:Receptors, Antigen, T-Cell; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D051746:ZAP-70 Protein-Tyrosine Kinase; C491734:Lat protein, mouse; C528034:Shc1 protein, mouse; C054979:antigen T cell receptor, zeta chain; C497262:Zap70 protein, mouse; C498155:Cd38 protein, mouse