Plasma membrane subdomain partitioning of Lck in primary human T lymphocytes

2010 ◽  
Vol 88 (4) ◽  
pp. 487-496 ◽  
Author(s):  
Claudine Irles ◽  
Joel Arias-Martinez ◽  
José Guzmán-Bárcenas ◽  
Alicia Ortega

Uncovering the plasma membrane distribution of tyrosine kinase Lck is crucial to understanding T lymphocyte triggering. Several studies of Lck species partitioning have given contradictory results. We decided to re-address this point by using phospho-specific antibodies to characterize active and inactive Lck partitioning in raft and non-raft membranes from primary human peripheral blood T lymphocytes. We show that most inactive Lck was localized in rafts and was associated with nearly all CD4 coreceptors and its negative regulator Csk in resting cells, while T cell receptor (TCR) engagement promoted a sustained dephosphorylation of inactive Lck. In contrast, active Lck had a more discrete distribution interacting with only a small number of CD4 coreceptors, and the kinase showed a rapid and short phosphorylation after TCR triggering. The differences in distribution and kinetics may be related to T lymphocyte signalling threshold modulation by Lck species and suggest how TCR triggering is first initiated. This study furthers our knowledge of the TCR activation model in primary human T lymphocytes.

Blood ◽  
1996 ◽  
Vol 87 (2) ◽  
pp. 682-690 ◽  
Author(s):  
OR Baricordi ◽  
D Ferrari ◽  
L Melchiorri ◽  
P Chiozzi ◽  
S Hanau ◽  
...  

We investigated the effect of pharmacologic modulation of the ATP receptor on intracellular ion changes and proliferative response of human peripheral blood lymphocytes (PBLs) and purified T lymphocytes. Extracellular ATP (ATPe) triggered in these cells an increase in the cytoplasmic Ca2+ concentration ([Ca2+]i) and plasma membrane depolarization. Whereas both Ca2+ release from intracellular stores and influx across the plasma membrane were detected in the whole PBL population, only Ca2+ influx was observed in T cells. In the presence of near physiologic extracellular Na+ concentrations (125 mmol/L), Ca2+ permeability through the ATPe-gated channel was very low, suggesting a higher selectivity for monovalent over divalent cations. The selective P2Z agonist benzoylbenzoic ATP (BzATP) increased [Ca2+]i in the presence but not the absence of extracellular Ca2+ and also caused plasma membrane depolarization. The covalent blocker oxidized ATP (oATP), an inhibitor of P2X and P2Z receptors, prevented Ca2+ influx and plasma membrane depolarization, but had no effect on Ca2+ release from stores. Stimulation with ATPe alone had no significant effects on PBL 3H-thymidine incorporation. On the contrary, ATPe or BzATP had a synergistic effect on DNA synthesis stimulated by selective T-cell mitogens such as phytohemagglutinin, anti-CD3 monoclonal antibody, or allogenic PBLs (mixed lymphocyte cultures). Treatment with oATP inhibited mitogenic stimulation by these receptor-directed agents but not by the combined application of the Ca2+ ionophore ionomycin and phorbol myristate acetate. Interleukin-2 partially relieved inhibition by oATP. These results suggest that human T lymphocytes express a plasma membrane channel gated by ATPe that is involved in mitogenic stimulation.


2002 ◽  
Vol 364 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Alessandra GAMBERUCCI ◽  
Emanuele GIURISATO ◽  
Paola PIZZO ◽  
Maristella TASSI ◽  
Roberta GIUNTI ◽  
...  

In Jurkat and human peripheral blood T-lymphocytes, 1-oleoyl-2-acetyl-sn-glycerol (OAG), a membrane-permeant analogue of diacylglycerol, activated the influx of Ca2+, Ba2+ and Sr2+. OAG also caused plasma-membrane depolarization in Ca2+-free media that was recovered by the addition of bivalent cation, indicating the activation of Na+ influx. OAG-induced cation influx was (i) mimicked by the natural dacylglycerol 1-stearoyl-2-arachidonyl-sn-glycerol, (ii) not blocked by inhibiting protein kinase C or in the absence of phopholipase C activity and (iii) blocked by La3+ and Gd3+. Differently from OAG, both thapsigargin and phytohaemagglutinin activated a potent influx of Ca2+, but little influx of Ba2+ and Sr2+. Moreover, the influx of Ca2+ activated by thapsigargin and that activated by OAG were additive. Furthermore, several drugs (i.e. econazole, SKF96365, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, 2-aminoethoxy diphenylborate and calyculin-A), while inhibiting the influx of Ca2+ induced by both thapsigargin and phytohaemagglutinin, did not affect OAG-stimulated cation influx. Transient receptor potential (TRP) 3 and TRP6 proteins have been shown previously to be activated by diacylglycerol when expressed heterologously in animal cells [Hofmann, Obukhov, Schaefer, Harteneck, Gudermann and Schultz (1999) Nature (London) 397, 259–263]. In both Jurkat and peripheral blood T-lymphocytes, mRNA encoding TRP proteins 1, 3, 4 and 6 was detected by reverse transcriptase PCR, and the TRP6 protein was detected by Western blotting in a purified plasma-membrane fraction. We conclude that T-cells express a diacylglycerol-activated cation channel, unrelated to the channel involved in capacitative Ca2+ entry, and associated with the expression of TRP6 protein.


Blood ◽  
1995 ◽  
Vol 85 (4) ◽  
pp. 1043-1052 ◽  
Author(s):  
H Schwarz ◽  
J Valbracht ◽  
J Tuckwell ◽  
J von Kempis ◽  
M Lotz

We recently identified a gene that is induced by lymphocyte activation (ILA). The sequence of the full-length 1.4-kb cDNA characterized ILA as a new member of the nerve growth factor/tumor necrosis factor (NGF/TNF) receptor family and the human homologue of the murine T-cell-specific receptor 4–1BB. The present study demonstrates ILA mRNA isoforms at 4.4, 4.0, and 1.8 kb in poly-A+ RNA from activated, but not from resting human peripheral blood T lymphocytes. A reverse transcriptase- polymerase chain reaction (RT-PCR) assay was used to study tissue distribution and regulation of ILA expression. The gene was induced in T lymphocytes by phytohemagglutinin (PHA), phorbol myristate acetate (PMA), and antibody to CD3, in B lymphocytes by PMA and antibodies to cell surface Ig, and in blood monocytes by interleukin-1 beta (IL-1 beta), lipopolysaccharide (LPS), and PMA. In T lymphocytes, ILA mRNA was detectable 1.5 hours after stimulation, reached maximal levels at 8 hours, and declined to background levels by 48 hours. Induction of ILA mRNA required protein synthesis and was primarily due to increased transcription. Actinomycin D reduced ILA mRNA levels in activated lymphocytes 50% within 30 minutes, demonstrating a relatively short half-life of this mRNA. Analysis of nonlymphoid cells showed that ILA mRNA was not detectable in resting cells. However, in contrast to the lymphoid-specific expression of the murine 4-–1BB gene, ILA was detected in nonlymphoid cells, including epithelial and hepatoma cells after stimulation with IL-1 beta. ILA was not detectable in several brain derived cell lines. The ILA cDNA encodes a 30-kD protein as demonstrated by in vitro translation, and this protein is immunoprecipitated by antisera that were raised against ILA peptides or a glutathione-S-transferase fusion protein. Flow cytometry showed expression of ILA protein on a subset of activated T or B lymphocytes. In conclusion, activation-dependent expression of ILA is found not only in T lymphocytes, but also in B lymphocytes, monocytes, and diverse nonlymphoid cell types.


2012 ◽  
Vol 287 (45) ◽  
pp. 38168-38177 ◽  
Author(s):  
Madhumouli Chatterjee ◽  
Christian M. Hedrich ◽  
Thomas Rauen ◽  
Christina Ioannidis ◽  
Cox Terhorst ◽  
...  

1987 ◽  
Vol 166 (1) ◽  
pp. 277-282 ◽  
Author(s):  
S Ferrini ◽  
C Bottino ◽  
R Biassoni ◽  
A Poggi ◽  
R P Sekaly ◽  
...  

Four clones were derived from human peripheral blood T lymphocytes from which CD4+ and CD8+ cells had been removed by treatment with specific mAbs and complement. All expressed the CD2+, 3+, 4-, 8-, T44- phenotype, and did not react with the WT31 mAb, which is specific for a framework determinant of the CD3-associated alpha/beta heterodimer which serves as receptor for antigen on most human T lymphocytes. Surface iodination followed by crosslinking with dithiobis-succinimidyl propionate (DSP) and immunoprecipitation with anti-CD3 mAbs indicated that, in all four clones, the CD3-associated molecules consisted of a major 45 kD band and a minor band of 43 kD. Northern blot analysis showed that mRNA for the gamma chain was expressed at high levels, whereas mRNA for the alpha chain was missing; beta chain mRNA was present in a defective form (1 kb instead of 1.3 kb). These data support the concept that these clones may express, in association with CD3, the molecular product of the T cell receptor gamma genes instead of the typical alpha/beta heterodimer. CD3+, WT31- clones lysed the NK-sensitive K562 target cells and produced IL-2 upon stimulation with PHA. In addition, they released IL-2 after triggering with soluble anti-CD3 mAbs or with an appropriate combination of anti-CD2 mAbs (in the presence of adherent cells). When CD3+, WT31- clones were incubated with an anti-CD3 producing hybridoma as triggering target, the latter was efficiently lysed. Target cell lysis also occurred when a suitable combination of anti-CD2 mAbs-producing hybridomas was used. Therefore, CD3+, WT31- cells appear to use two pathways of cell activation that function also in conventional CD3+, WT31+ T cells, but they lack a third putative pathway initiated by T44 surface molecules.


2005 ◽  
Vol 564 (1) ◽  
pp. 131-143 ◽  
Author(s):  
Jennifer R. Robbins ◽  
Susan Molleran Lee ◽  
Alexandra H. Filipovich ◽  
Peter Szigligeti ◽  
Lisa Neumeier ◽  
...  

Blood ◽  
1998 ◽  
Vol 91 (10) ◽  
pp. 3901-3908 ◽  
Author(s):  
Subburaj Ilangumaran ◽  
Anne Briol ◽  
Daniel C. Hoessli

CD44 is the major cell surface receptor for the extracellular matrix glycosaminoglycan hyaluronan and is implicated in a variety of biological events that include embryonic morphogenesis, lymphocyte recirculation, inflammation, and tumor metastasis. CD44 delivers activation signals to T lymphocytes, B lymphocytes, natural killer cells, polymorphonuclear leukocytes, and macrophages by stimulating protein tyrosine phosphorylation and calcium influx. The mechanism of signal transduction via CD44 remains undefined, although CD44 was shown to physically associate with intracellular protein tyrosine kinase Lck in T lymphocytes. In the present report, we show that a significant proportion of CD44 in human peripheral blood T lymphocytes and endothelial cells is associated with low-density plasma membrane fractions that represent specialized plasma membrane domains enriched in glycosphingolipids and glycosylphosphatidylinositol (GPI)-anchored proteins. CD44 and the GPI-anchored CD59 do not appear to directly interact in the low-density membrane fractions. In human peripheral blood T lymphocytes, 20% to 30% of the Src family protein tyrosine kinases, Lck and Fyn, are recovered from these fractions. CD44-associated protein kinase activity was selectively recovered from the low-density membrane fractions, corresponding to glycosphingolipid-rich plasma membrane microdomains. Reprecipitation of the in vitro phosphorylated proteins showed that CD44 associates not only with Lck but also with Fyn kinase in these membrane domains. Our results suggest that cellular stimulation via CD44 may proceed through the signaling machinery of glycosphingolipid-enriched plasma membrane microdomains and, hence, depend on the functional integrity of such domains.


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