Human T-cell receptor triggering requires inactivation of Lim kinase-1 by Slingshot-1 phosphatase.

Actin dynamics control early T-cell receptor (TCR) signalling during T-cell activation. However, the precise regulation of initial actin rearrangements is not completely understood. Here, we have investigated the regulatory role of the phosphatase Slingshot-1 (SSH1) in this process.

T cell activation and effector function in the human Jurkat T cell model.

In order to understand T cell function, it is necessary to completely decipher the molecular dynamics underlying T cell activation and effector function. In vitro easy-to-handle cellular models are valuable tools to study intracellular molecular mechanisms in live cells. The CD4 T cell line Jurkat (JK) has been widely employed to investigate intracellular signaling leading to T cell activation in response to T cell receptor (TCR) triggering.

Activation kinetics of regulatory molecules during immunological synapse in T cells.

T cell activation through TCR stimulation leads to the formation of the immunological synapse (IS), a specialized adhesion organized between T lymphocytes and antigen presenting cells (APCs) in which a dynamic interaction among signaling molecules, the cytoskeleton and intracellular organelles achieves proper antigen-mediated stimulation and effector function. The kinetics of molecular reactions at the IS is essential to determine the quality of the response to the antigen stimulation. Herein, we describe methods based on biochemistry, flow cytometry and imaging in live and fixed cells to study the activation state and dynamics of regulatory molecules at the IS in the Jurkat T cell line CH7C17 and primary human and mouse CD4 T lymphocytes stimulated by antigen presented by Raji and HOM2 B cell lines and human and mouse dendritic cells.

Erythroid SLC7A5/SLC3A2 amino acid carrier controls red blood cell size and maturation.

Inhibition of the heterodimeric amino acid carrier SLC7A5/SLC3A2 (LAT1/CD98) has been widely studied in tumor biology but its role in physiological conditions remains largely unknown. Here we show that the SLC7A5/SLC3A2 heterodimer is constitutively present at different stages of erythroid differentiation but absent in mature erythrocytes. Administration of erythropoietin (EPO) further induces SLC7A5/SLC3A2 expression in circulating reticulocytes, as it also occurs in anemic conditions.

T cell asymmetry and metabolic crosstalk can fine-tune immunological synapses.

T cell asymmetry upon specific cell-cell interactions during mammalian immunological synapse (IS) contacts requires mammalian target of rapamycin complex (mTORC) activation and chaperones, such as the eukaryotic chaperonin containing TCP1 (CCT) for protein synthesis and folding. This mechanism can control cytoskeleton dynamics, and regulate mitochondrial fate, respiration, and metabolic rates, ultimately underlying cell reprogramming events that are relevant for CD4 T cell functional outcomes.

Folding for the Immune Synapse: CCT Chaperonin and the Cytoskeleton.

Lymphocytes rearrange their shape, membrane receptors and organelles during cognate contacts with antigen-presenting cells (APCs). Activation of T cells by APCs through pMHC-TCR/CD3 interaction (peptide-major histocompatibility complex-T cell receptor/CD3 complexes) involves different steps that lead to the reorganization of the cytoskeleton and organelles and, eventually, activation of nuclear factors allowing transcription and ultimately, replication and cell division. Both the positioning of the lymphocyte centrosome in close proximity to the APC and the nucleation of a dense microtubule network beneath the plasma membrane from the centrosome support the T cell's intracellular polarity.

Adhesive Interactions Delineate the Topography of the Immune Synapse.

T cells form adhesive contacts with antigen-presenting cells (APCs) as part of the normal surveillance process that occurs in lymph nodes and other tissues. Most of these adhesive interactions are formed by integrins that interact with ligands expressed on the surface of the APC. The interactive strength of integrins depends on their degree of membrane proximity as well as intracellular signals that dictate the conformation of the integrin.

Sailing to and Docking at the Immune Synapse: Role of Tubulin Dynamics and Molecular Motors.

The different cytoskeleton systems and their connecting molecular motors move vesicles and intracellular organelles to shape cells. Polarized cells with specialized functions display an exquisite spatio-temporal regulation of both cytoskeletal and organelle arrangements that support their specific tasks. In particular, T cells rapidly change their shape and cellular function through the establishment of cell surface and intracellular polarity in response to a variety of cues.

Microtubule-associated protein-4 controls nanovesicle dynamics and T cell activation.

The immune synapse (IS) is a specialized structure formed at the contact area between T lymphocytes and antigen-presenting cells (APCs) that is essential for the adaptive immune response. Proper T cell activation requires its polarization towards the APC, which is highly dependent on the tubulin cytoskeleton. Microtubule-associated protein-4 (MAP4) is a microtubule (MT)-stabilizing protein that controls MTs in physiological processes, such as cell division, migration, vesicular transport or primary cilia formation.

Orchestrating Lymphocyte Polarity in Cognate Immune Cell-Cell Interactions.

The immune synapse (IS) is a specialized structure established between different immune cells that fulfills several functions, including a role as a communication bridge. This intimate contact between a T cell and an antigen-presenting cell promotes the proliferation and differentiation of lymphocytes involved in the contact. T-cell activation requires the specific triggering of the T-cell receptor (TCR), which promotes the activation of different signaling pathways inducing the polarization of the T cell.

HDAC6 is a Regulator of CTL Function through Control of Lytic Granule Dynamics.

Viral infections involve specific stress exposure that can influence the quality and average lifespan of an organism. The immune system acts through virus clearance from the organism. Many aspects of immune cells accounting for this response are still under study.

HDAC6 regulates the dynamics of lytic granules in cytotoxic T lymphocytes.

HDAC6 is a tubulin deacetylase involved in many cellular functions related to cytoskeleton dynamics, including cell migration and autophagy. In addition, HDAC6 affects antigen-dependent CD4(+)T cell activation. In this study, we show that HDAC6 contributes to the cytotoxic function of CD8(+)T cells.

Immune synapse: conductor of orchestrated organelle movement.

To ensure proper cell function, intracellular organelles are not randomly distributed within the cell, but polarized and highly constrained by the cytoskeleton and associated adaptor proteins. This relationship between distribution and function was originally found in neurons and epithelial cells; however, recent evidence suggests that it is a general phenomenon occurring in many highly specialized cells including T lymphocytes. Recent studies reveal that the orchestrated redistribution of organelles is dependent on antigen-specific activation of and immune synapse (IS) formation by T cells.

The diagnostic and therapeutic importance of human growth hormone isoforms.

The study of human growth hormone isoforms has conduced to the elaboration of patents related to very important items: codifying and regulatory sequences, production of the protein at large-scale, modifications to prolong half-life as monomer, dimer and fusion protein for treatments directed to growth-associated diseases. The designs to identification and quantification of hGH are besides the formers establishing very important basis of patented sources that can be used for a specific and opportune diagnosis and treatment of biological abnormalities or undesirable effects when these growth hormones are involved.

Tubulin and actin interplay at the T cell and antigen-presenting cell interface.

T cells reorganize their actin and tubulin-based cytoskeletons to provide a physical basis to the immune synapse. However, growing evidence shows that their roles on T cell activation are more dynamic than merely serving as tracks or scaffold for different molecules. The crosstalk between both skeletons may be important for the formation and movement of the lamella at the immunological synapse by increasing the adhesion of the T cell to the antigen-presenting cells (APC), thus favoring the transport of components toward the plasma membrane and in turn regulating the T-APC intercellular communication.

Activation outcomes induced in naïve CD8 T-cells by macrophages primed via "phagocytic" and nonphagocytic pathways.

The array of phagocytic receptors expressed by macrophages make them very efficient at pathogen clearance, and the phagocytic process links innate with adaptive immunity. Primary macrophages modulate antigen cross-presentation and T-cell activation. We assessed ex vivo the putative role of different phagocytic receptors in immune synapse formation with CD8 naïve T-cells from OT-I transgenic mice and compared this with the administration of antigen as a soluble peptide.