T Cell Receptor Engagement Leads to Phosphorylation of Clathrin Heavy Chain during Receptor Internalization

Crotzer, Victoria L.; Mabardy, Allan; Weiss, Arthur; Brodsky, Frances M.

doi:10.1084/jem.20031105

Cited by 56 publications

(59 citation statements)

References 53 publications

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“…Also, PP1 and PP2, two other SFK inhibitors, had no effect on the toxin uptake (our unpublished data). Thus, in contrast to the results reported for BCR (Stoddart et al, 2002), T-cell receptor (TCR) (Crotzer et al, 2004) and EGF receptor (EGFR) (Wilde et al, 1999), Src or a related kinase does not seem to be involved in regulation of Stx endocytosis. The fact that endocytosis of Stx can be reduced by piceatannol to almost the same extent as observed in the presence of genistein suggests that the main tyrosine kinase involved in Stx uptake in HeLa cells is Syk.…”

contrasting

confidence: 46%

Shiga Toxin Regulates Its Entry in a Syk-dependent Manner

Lauvrak

Wälchli

Iversen

et al. 2006

MBoC

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Shiga toxin (Stx) is composed of an A-moiety that inhibits protein synthesis after translocation into the cytosol, and a B-moiety that binds to Gb3 at the cell surface and mediates endocytosis of the toxin. After endocytosis, Stx is transported retrogradely to the endoplasmic reticulum, and then the A-fragment enters the cytosol. In this study, we have investigated whether toxin-induced signaling is involved in its entry. Stx was found to activate Syk and induce rapid tyrosine phosphorylation of several proteins, one protein being clathrin heavy chain. Toxin-induced clathrin phosphorylation required Syk activity, and in cells overexpressing Syk, a complex containing clathrin and Syk could be demonstrated. Depletion of Syk by small interfering RNA, expression of a dominant negative Syk mutant (Syk KD), or treatment with the Syk inhibitor piceatannol inhibited not only Stx-induced clathrin phosphorylation but also endocytosis of the toxin. Also, Golgi transport of Stx was inhibited under all these conditions. In conclusion, our data suggest that Stx regulates its entry into target cells. INTRODUCTIONThe bacterial toxin Shiga toxin (Stx) inhibits protein synthesis in cells after first binding to Gb3 at the cell surface. Then, the toxin is endocytosed, and thereafter it is transported retrogradely to the Golgi apparatus and the endoplasmic reticulum (ER) before being translocated to the cytosol where it inactivates the ribosomes enzymatically (for reviews, see . The toxin is composed of two moieties: the enzymatically active A-chain that is noncovalently attached to a stable pentamer of B-chains that binds to Gb3 and mediates the endocytic uptake of the toxin. In some cells, Stx is endocytosed mainly by clathrin-dependent endocytosis , although other mechanisms exist (Nichols et al., 2001;Lauvrak et al., 2004;Saint-Pol et al., 2004). Importantly, the toxin can induce its own transport to clathrin-coated pits (Sandvig et al., 1989). When Stx is added to HeLa cells at 0°C, the toxin becomes evenly distributed at the cell surface. However, after a short incubation at 37°C, the toxin moves to clathrin-coated pits and is internalized. In toxin-sensitive cells a larger fraction of the toxin seems to be internalized from clathrin-coated pits at the cell surface, and clathrin is required for endosome-to-Golgi transport of the toxin as well (Lauvrak et al., 2004;Saint-Pol et al., 2004). Because it has been shown by different groups that the fatty acid of Gb3 is important for efficient Golgi transport (Sandvig et al., 1994;Lingwood, 1999), the composition of Gb3 also may play a role for the endocytic pathway used. A raft localization of StxB was recently found to be required for efficient retrograde transport (Falguieres et al., 2001).In some hematopoetic cells, Stx has been shown to trigger a rapid signaling cascade that might lead to apoptosis (for review, see Cherla et al., 2003). In a number of other cell types induction of signaling leading to apoptosis seems to be mediated by the ribocytotoxic stress induced by the A-fr...

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contrasting

confidence: 46%

Shiga Toxin Regulates Its Entry in a Syk-dependent Manner

Lauvrak

Wälchli

Iversen

et al. 2006

MBoC

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“…14,20 Although the exact mechanisms of TCR internalization are still poorly understood, it in part depends on clathrin-mediated endocytosis. 13 Our observations suggest that low-dose CD95 engagement enhances the TCR translocation. However, it is still unclear how this mechanistically relates to CD95 endocytosis and to the generation of a common growthpromoting signaling platform.…”

Section: Modulation Of Primary T-cell Activation By Cd95mentioning

confidence: 66%

“…TCR/ CD3 complex internalization is associated with optimal activation through the formation of intracellular signaling platforms. 13 As shown in Figure 5a and b and Supplementary Figure S10A,B, FACS analyses revealed a significant augmentation of CD3-driven TCR internalization by Figure 4 CD95 promotes upregulation of activation markers and ERK activation. Purified human CD4 þ T cells were incubated in X-VIVO medium with immobilized anti-CD3 mAb or PHA for the indicated time periods in the presence or absence of plate-bound anti-CD95 mAb anti-APO-1 (5 mg/ml) (a-c, e and f) or CD95L-ST-Fc (2,5 mg/ml) (e) as well as high doses of CD95L-ST-Fc (d) or CD95LFc (f) (both 20 mg/ml).…”

Section: Modulation Of Primary T-cell Activation By Cd95mentioning

confidence: 98%

Modulation of CD4+ T-cell activation by CD95 co-stimulation

et al. 2010

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CD95 is a dual-function receptor that exerts pro-or antiapoptotic effects depending on the cellular context, the state of activation, the signal threshold and the mode of ligation. In this study, we report that CD95 engagement modulates TCR/CD3-driven signaling pathways in resting T lymphocytes in a dose-dependent manner. While high doses of immobilized CD95 agonists silence T cells, lower concentrations augment activation and proliferation. We analyzed the co-stimulatory capacity of CD95 in detail in resting human CD4 þ T cells, and demonstrate that low-dose ligand-induced co-internalization of CD95 and TCR/CD3 complexes enables non-apoptotic caspase activation, the prolonged activation of MAP kinases, the upregulation of antiapoptotic proteins associated with apoptosis resistance, and the activation of transcription factors and cell-cycle regulators for the induction of proliferation and cytokine production. We propose that the levels of CD95L on antigen-presenting cells (APCs), neighboring T cells or epithelial cells regulate inhibitory or co-stimulatory CD95 signaling, which in turn is crucial for fine-tuning of primary T-cell activation. Cell Death and Differentiation (2011) 18, 619-631; doi:10.1038/cdd.2010.134; published online 5 November 2010For activation of resting T cells, two signals are required. The first signal emerges from an engagement of the T cell receptor (TCR)/CD3 complex, whereas the second signal is generated through the ligation of co-stimulatory receptors (i.e. CD28). Recently, 'tumor necrosis factor (TNF) receptor-associated factor' (TRAF) binding receptors were identified as a second class of co-stimulatory receptors. 1 As an example, Alderson et al. 2,3 provided first evidence for the role of CD95 (Fas, APO-1), the prototypic death receptor of the immune system, in the activation of human T cells. It was subsequently reported that CD3-crosslinking alone or CD3/CD95 costimulation induces the processing of caspase-8 and/or caspase-3 as a prerequisite for full T-cell proliferation. [4][5][6] CD95 co-ligation also influences several other routes of intracellular signal transduction. Kataoka et al. 7 reported the activation of NF-kB-and mitogen-activated protein kinase (MAPK)-related pathways following an interaction of CD95-recruited 'cellular FLICE-inhibitory protein' (cFLIP) with downstream signaling molecules. Apparently, this process required the cleavage of cFLIP into a p43 fragment. More recently, however, it was argued that p22-FLIP (but not p43) can activate NF-kB by directly interacting with the IKK complex. 8 So far, three cFLIP isoforms (cFLIP L , cFLIP S and cFLIP R ) were identified, with cFLIP S/R mediating a block in apoptosis by inhibiting procaspase-8 at the death-inducing signaling complex (DISC). The role of cFLIP L regarding an inhibition at the DISC is still a matter of debate. 8,9 Further downstream, antiapoptotic proteins including Bcl-2/Bcl-X L and 'X-linked inhibitor-of-apoptosis protein' (XIAP) may prevent apoptosis. 9,10 A decreased expression of antiapoptotic c...

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“…The clathrin-dependent pathway has been shown to be the primary pathway for ligand-induced BCR endocytosis, and raft structures appear to be required for efficient phosphorylation of clathrin heavy chain [21,33]. Tyrosine-phosphorylation of clathrin heavy chain is induced by an SRC-type protein kinase in response to stimulation of various receptor types, and the level of phosphorylation correlates with the rate of receptor internalization [21,[34][35][36][37]. Our data support a requirement for phosphorylation of clathrin heavy chain as well as for that of other endocytosis-related factors in BCR internalization.…”

Section: Discussionmentioning

confidence: 99%

Large‐scale proteomic analysis of tyrosine‐phosphorylation induced by T‐cell receptor or B‐cell receptor activation reveals new signaling pathways

et al. 2009

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Activation of the T-cell receptor (TCR) and that of the B-cell receptor (BCR) elicits tyrosinephosphorylation of proteins that belongs to similar functional categories, but result in distinct cellular responses. Large-scale analyses providing an overview of the signaling pathways downstream of TCR or BCR have not been described, so it has been unclear what components of these pathways are shared and which are specific. We have now performed a systematic analysis and provide a comprehensive list of tyrosine-phosphorylated proteins (PY proteome) with quantitative data on their abundance in T cell, B cell, and nonlymphoid cell lines. Our results led to the identification of novel tyrosine-phosphorylated proteins and signaling pathways not previously implicated in immunoreceptor signal transduction, such as clathrin, zonula occludens 2, eukaryotic translation initiation factor 3, and RhoH, suggesting that TCR or BCR signaling may be linked to downstream processes such as endocytosis, cell adhesion, and translation. Thus comparative and quantitative studies of tyrosine-phosphorylation have the potential to expand knowledge of signaling networks and to promote understanding of signal transduction at the system level.

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T Cell Receptor Engagement Leads to Phosphorylation of Clathrin Heavy Chain during Receptor Internalization

Cited by 56 publications

References 53 publications

Shiga Toxin Regulates Its Entry in a Syk-dependent Manner

Shiga Toxin Regulates Its Entry in a Syk-dependent Manner

Modulation of CD4+ T-cell activation by CD95 co-stimulation

Large‐scale proteomic analysis of tyrosine‐phosphorylation induced by T‐cell receptor or B‐cell receptor activation reveals new signaling pathways

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