The Actin Cytoskeleton in T Cell Activation

Burkhardt, Janis K.; Carrizosa, Esteban; Shaffer, Meredith H.

doi:10.1146/annurev.immunol.26.021607.090347

Cited by 287 publications

(320 citation statements)

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“…A proline-rich domain enables binding to SH3 domain-containing proteins including the Src kinases Lck [20] and Lyn [21]. An SH3 domain forms the C-terminal part of the molecule [3,22]. Moreover, HS1 contains several tyrosine motifs and is a substrate of Src and Syk kinases in several hematopoietic cell types [23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…Since all these processes crucially depend on dynamic changes of the lymphocyte cytoskeleton, the engagement of T-cell surface receptors (including the TCR, chemokine receptors, and integrins) activates multiple actin-regulatory proteins that work in concert to adjust actin polymerization. This regulatory network also includes the adapter proteins Nck and HS1 (reviewed in [1][2][3][4]). The Nck (noncatalytic region of tyrosine kinase) family of adapter proteins comprises two members (Nck1/Nckα and Nck2/Nckβ, also termed Grb4) that are structurally and functionally redundant in many aspects [5].…”

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SDF1α‐induced interaction of the adapter proteins Nck and HS1 facilitates actin polymerization and migration in T cells

2014

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Noncatalytic region of tyrosine kinase (Nck) is an adapter protein that comprises one SH2 (Src homology) domain and three SH3 domains. Nck links receptors and receptorassociated tyrosine kinases or adapter proteins to proteins that regulate the actin cytoskeleton. Whereas the SH2 domain binds to phosphorylated receptors or associated phosphoproteins, individual interactions of the SH3 domains with proline-based recognition motifs result in the formation of larger protein complexes. In T cells, changes in cell polarity and morphology during T-cell activation and effector function require the T-cell receptor-mediated recruitment and activation of actin-regulatory proteins to initiate cytoskeletal reorganization at the immunological synapse. We previously identified the adapter protein HS1 as a putative Nck-interacting protein. We now demonstrate that the SH2 domain of Nck specifically interacts with HS1 upon phosphorylation of its tyrosine residue 378. We report that in human T cells, ligation of the chemokine receptor CXCR4 by stromal cell-derived factor 1α (SDF1α) induces a rapid and transient phosphorylation of tyrosine 378 of HS1 resulting in an increased association with Nck. Consequently, siRNA-mediated downregulation of HS1 and/or Nck impairs SDF1α-induced actin polymerization and T-cell migration.Keywords: CXCR4 r HS1 r Nck r SDF1α r T cells IntroductionT cells govern adaptive immunity by cytokine secretion or cytotoxic effector function. After development in the thymus, naive T lymphocytes constantly recirculate between the blood stream and lymphoid tissues. At the molecular level, this homing and migration processes rely on complex interactions of selected chemokines with their receptors on respective T cells and of T-cell adhesion molecules binding to their ligands on endothelial cells or the extracellular matrix. Individual interactions elicit specific signaling pathways that induce dynamic cytoskeletal rearrangements, which enable lymphocytes to adhere to or pass a certain substrate or to transmigrate through a given endothelium. Morphologically, circular floating T cells adopt a migratory phenotype characterized Correspondence: Dr. Marcus Lettau e-mail: lettau@immunologie.uni-kiel.de by a leading edge at the front and an uropod at the rear. When T cells encounter their antigen on an antigen-presenting cell in the lymph nodes or spleen, migration is halted and the cells rapidly polarize toward the intercellular contact area. The subsequent formation of the so-called immunological synapse (IS) is again accompanied by complex cytoskeletal changes and comprises the structural basis for T-cell activation. This primary antigenic stimulation ultimately results in cell-cycle progression, clonal expansion, and differentiation to T-effector cells. The activated T cells regain migratory potential, leave the lymphoid tissue, and search the periphery for infected or transformed cells displaying their cognate antigen. Upon antigen encounter, the T cells adhere to their target cell and polarize toward the intercell...

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

SDF1α‐induced interaction of the adapter proteins Nck and HS1 facilitates actin polymerization and migration in T cells

2014

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“…ezrin ͉ kinase specificity ͉ knockout ͉ migration ͉ moesin T he ERM family in mammals consists of 3 closely related members: ezrin, radixin and moesin whose major function is to link cortical actin filaments to the plasma membrane (1)(2)(3)(4). ERM N terminus (the FERM/band 4.1 domain) binds to plasma membrane both by direct interaction with phospholipids and by binding cytoplasmic tails of transmembrane proteins such as CD43, CD44, and ICAMs.…”

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confidence: 99%

LOK is a major ERM kinase in resting lymphocytes and regulates cytoskeletal rearrangement through ERM phosphorylation

Belkina

Liu

Hao

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

131

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ERM (ezrin-radixin-moesin) proteins mediate linkage of actin cytoskeleton to plasma membrane in many cells. ERM activity is regulated in part by phosphorylation at a C-terminal threonine, but the identity of ERM kinases is unknown in lymphocytes and incompletely defined in other mammalian cells. Our studies show that lymphocyte-oriented kinase (LOK) is an ERM kinase in vitro and in vivo. Mass spectrometric analysis indicates LOK is abundant at the lymphocyte plasma membrane and immunofluorescence studies show LOK enrichment at the plasma membrane near ERM. In vitro peptide specificity analyses characterize LOK as a basophilic kinase whose optimal substrate sequence resembles the ERM site, including unusual preference for tyrosine at P-2. LOK's activity on moesin peptide and protein was comparable to reported ERM kinases ROCK and PKC but unlike them LOK displayed preferential specificity for moesin compared to traditional basophilic kinase substrates. Two genetic approaches demonstrate a role for LOK in ERM phosphorylation: cell transfection with LOK kinase domain augments ERM phosphorylation and lymphocytes from LOK knockout mice have >50% reduction in ERM phosphorylation. The findings on localization and specificity argue that LOK is a direct ERM kinase. The knockout mice have normal hematopoietic cell development but notably lymphocyte migration and polarization in response to chemokine are enhanced. These functional alterations fit the current understanding of the role of ERM phosphorylation in regulating cortical reorganization. Thus, these studies identify a new ERM kinase of importance in lymphocytes and confirm the role of ERM phosphorylation in regulating cell shape and motility.ezrin ͉ kinase specificity ͉ knockout ͉ migration ͉ moesin T he ERM family in mammals consists of 3 closely related members: ezrin, radixin and moesin whose major function is to link cortical actin filaments to the plasma membrane (1-4). ERM N terminus (the FERM/band 4.1 domain) binds to plasma membrane both by direct interaction with phospholipids and by binding cytoplasmic tails of transmembrane proteins such as CD43, CD44, and ICAMs. ERM C terminus (''tail'') binds to filamentous actin. ERMs exist not only in this active conformation, but also in an inactive conformation where the C terminus binds to the FERM domain, thereby blocking binding sites on both FERM and tail. There is an evolutionarily conserved phosphorylation site near the C terminus whose phosphorylation contributes to stabilizing the active conformation. In mitotic cells ERM phosphorylation is critical for achieving spherical morphology and rigidity (5, 6). For lymphocytes circulating in blood, ERM phosphorylation is understood to contribute to rigidity and maintenance of microvilli. In response to chemotactic factors (especially chemokines) those lymphocytes transition into flexible migrating cells concurrent with rapid extensive dephosphorylation of ERM, which facilitates their polarization (7-10).Given the importance of ERM phosphorylation, it is essential to...

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“…The nodes added were restricted to proteins within our list and those which are directly interacting with each other. Some additional nodes such as cofilin1, STAT3 and stathmin previously demonstrated to be involved in LFA-1 signalling (Verma et al, 2009;Burkhardt et al, 2008) were subsequently added to further enrich the network (Fig. 8).…”

Section: In-silico Protein Network Analysis Of Identified Tyrosine Phmentioning

confidence: 99%

Analysis of dynamic tyrosine phosphoproteome in LFA‐1 triggered migrating t‐cells

Verma

Dempsey

Freeley

et al. 2011

Journal Cellular Physiology

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The ordered, directional migration of T-lymphocytes is a key process during immune surveillance and response. This requires cell adhesion to the high endothelial venules or to the extracellular matrix by a series of surface receptor/ligand interactions involving adhesion molecules of the integrin family including lymphocyte function associated molecule-1 (LFA-1) and intercellular adhesion molecules (ICAMs). Reversible protein phosphorylation is emerging as a key player in the regulation of biological functions with tyrosine phosphorylation playing a crucial role in signal transduction. Thus, the study of this type of post-translational modification at the proteomic level has great biological significance. In this work, phospho-enriched cell lysates from LFA-1-triggered migrating human T-cells were subjected to immunoaffinity purification of tyrosine phosphorylated proteins, mass spectrometric and bioinformatic analysis.In addition to the identification of several well-documented proteins, the analysis suggested involvement of a number of new and novel proteins in LFA-1 induced T-cell migration. This dataset expands the list of the signalling components of the LFA-1 induced phosphotyrosine protein complexes in migrating T-cells that will be extremely useful in the study of their specific roles within LFA-1 associated signalling pathways. Identification of proteins previously not reported in the context of LFA-1 stimulated signal transduction may provide new insights into understanding the LFA-1 signalling networks and aid in the search for new potential therapeutic targets.

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The Actin Cytoskeleton in T Cell Activation

Cited by 287 publications

References 167 publications

SDF1α‐induced interaction of the adapter proteins Nck and HS1 facilitates actin polymerization and migration in T cells

SDF1α‐induced interaction of the adapter proteins Nck and HS1 facilitates actin polymerization and migration in T cells

LOK is a major ERM kinase in resting lymphocytes and regulates cytoskeletal rearrangement through ERM phosphorylation

Analysis of dynamic tyrosine phosphoproteome in LFA‐1 triggered migrating t‐cells

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