Nk Cell Activation Pathway - fileof68’s blog

Introduction. NK cells are innate effector cells that assist in limiting the emergence of viral infections and cancers, and cooperate with dendritic cells DCs to.

Pathway NK Cell Activation Actin Cytoskeleton Regulation Apoptosis Regulation Pathway Insulin Signaling Pathway.

Natural killer NK cells are lymphocytes of the innate immune system that are involved in the early defenses against foreign cells, as well as autologous cells undergoing various forms of stress, such as microbial infection or tumor transformation. NK cell activation is controlled by a dynamic balance between complementary and antagonistic pathways that are initiated upon interaction with potential target cells. NK cells express an array of activating cell surface receptors that can trigger cytolytic programs, as well as cytokine or chemokine secretion. Some of these activating cell surface receptors initiate protein tyrosine kinase PTK -dependent pathways through noncovalent associations with transmembrane signaling adaptors that harbor intracytoplasmic ITAMs immunoreceptor tyrosine-based activation motifs. Additional cell surface receptors that are not directly coupled to ITAMs also participate in NK cell activation. These include NKG2D, which is noncovalently associated to the DAP10 transmembrane signaling adaptor, as well as integrins and cytokine receptors. NK cells also express cell surface inhibitory receptors that antagonize activating pathways through protein tyrosine phosphatases PTPs. These inhibitory cell surface receptors are characterized by intracytoplasmic ITIMs immunoreceptor tyrosine-based inhibition motifs. The tyrosine-phosphorylation status of several signaling components that are substrates for both PTKs and PTPs is thus key to the propagation of the NK cell effector pathways. Understanding the integration of these multiple signals is central to the understanding and manipulation of NK cell effector signaling pathways.

Natural killer cell inhibitory receptors Mol Function Receptor Pathway NK Cell Activation.

A delicate balance between positive and negative signals regulates NK cell effector function. Activation of NK cells may be initiated by the triggering of multi.

A delicate balance between positive and negative signals regulates NK cell effector function. Activation of NK cells may be initiated by the triggering of multiple adhesion or costimulatory molecules, and can be counterbalanced by inhibitory signals induced by receptors for MHC class I. A common pathway of inhibitory signaling is provided by immunoreceptor tyrosine-based inhibitory motifs ITIMs in the cytoplasmic domains of these receptors which mediate the recruitment of SH2 domain-bearing tyrosine phosphate-1 SHP-1. In contrast to the extensive progress that has been made regarding the negative regulation of NK cell function, our knowledge of the signals that activate NK cells is still poor. Recent studies of the activating receptor complexes have shed new light on the induction of NK cell effector function. Several NK receptors using novel adaptors with immunoreceptor tyrosine-based activation motifs ITAMs and with PI 3-kinase recruiting motifs have been implicated in NK cell stimulation.KeywordsNK cells; DAP12; DAP10; 2B4AbbreviationsADCC, antibody-dependent cellular cytotoxicity; cDNA, complementary deoxyribonucleic acid; HLA, human leukocyte antigen; IFN, interferon; Ig, immunoglobulin; Ig-SF, Ig superfamily; ILT, Ig-like transcript; ITAM, immunoreceptor tyrosine-based activation motif; ITIM, immunoreceptor tyrosine-based inhibition motif; KIR, killer cell Ig-like receptor; LIR, leukocyte Ig-like receptor; mAb, monoclonal antibody; MDL-1, myeloid DAP12-associating lectin-1; MHC, major histocompatibility complex; MIR, monocyte Ig-like receptor; NK, natural killer; PIR, paired Ig receptors; SH2, src-homology 2; SHP, SH2 domain-bearing tyrosine phosphatase

Natural killer cells or NK cells are a type of cytotoxic lymphocyte critical to the innate immune system. The role NK cells play is analogous to that of cytotoxic T.

NK cell activation: distinct stimulatory pathways counterbalancing inhibitory signals

1. Hum Immunol. 2000 Jan;61 1 :18-27. NK cell activation: distinct stimulatory pathways counterbalancing inhibitory signals. Bakker AB, Wu J, Phillips JH, Lanier LL.

Natural killer cell signaling pathways. NK cell activation is controlled by a dynamic balance between complementary and antagonistic pathways that are.