Analysis and design of three-stage concatenated color-shift keying

Visible Light Communication (VLC) relies on abundant unlicensed bandwidth resources. As an attractive high-data-rate modulation scheme designed for VLC, Color Shift Keying (CSK) assisted modulation is analysed. We commence our study from an uncoded M-CSK scheme relying on the joint Maximum Likelihood (ML) Hard-Detection (HD) of three colors, when communicating over an AWGN channel, where both empirical and analytical results are provided. We invoke EXtrinsic Information Transfer (EXIT) charts for designing a Maximum A-posteriori Probability (MAP) based Soft-Detection (SD) aided iterative receiver jointly detecting the three colors. Based on the EXIT characteristics of M-CSK, we design different signal labeling strategies for diverse color constellations and detection schemes, which are capable of achieving a substantially improved Bit Error Ratio (BER) performance. Thus, given a fixed transmission power, a CSK system using our proposed signal labeling is capable of increasing the reliable data transmission distance by about 30%

Csk, a Critical Link of G Protein Signals to Actin Cytoskeletal Reorganization

AbstractHeterotrimeric G proteins can signal to reorganize the actin cytoskeleton, but the mechanism is unclear. Here we report that, in tyrosine kinase Csk-deficient mouse embryonic fibroblast cells, G protein (Gβγ, Gα12, Gα13, and Gαq)-induced, and G protein-coupled receptor-induced, actin stress fiber formation was completely blocked. Reintroduction of Csk into Csk-deficent cells restored the G protein-induced actin stress fiber formation. Chemical rescue experiments with catalytic mutants of Csk demonstrated that the catalytic activity of Csk was required for this process. Furthermore, we uncovered that Gβγ can both translocate Csk to the plasma membrane and directly increase Csk kinase activity. Our genetic and biochemical studies demonstrate that Csk plays a critical role in mediating G protein signals to actin cytoskeletal reorganization

The tyrosine kinase CSK associates with FLT3 and c-Kit receptors and regulates downstream signaling.

Type III receptor tyrosine kinases (RTKs), FLT3 and c-Kit play important roles in a variety of cellular processes. A number of SH2-domain containing proteins interact with FLT3 and c-Kit and regulate downstream signaling. The SH2-domain containing non-receptor protein tyrosine kinase CSK is mainly studied in context of regulating Src family kinases. Here we present an addition role of this kinase in RTK signaling. We show that CSK interacts with FLT3 and c-Kit in a phosphorylation dependent manner. This interaction is facilitated through the SH2-domain of CSK. Under basal conditions CSK is mainly localized throughout the cytosolic compartment but upon ligand stimulation it is recruited to the inner side of cell membrane. CSK association did not alter receptor ubiquitination or phosphorylation but disrupted downstream signaling. Selective depletion of CSK using siRNA, or inhibition with CSK inhibitor, led to increased phosphorylation of Akt and Erk, but not p38, upon FLT3 ligand (FL) stimulation. Stem cell factor (SCF)-mediated Akt and Erk activation was also elevated by CSK inhibition. However, siRNA mediated CSK knockdown increased SCF stimulated Akt phosphorylation but decreased Erk phosphorylation. CSK depletion also significantly increased both FL- and SCF-induced SHC, Gab2 and SHP2 phosphorylation. Furthermore, CSK depletion contributed to oncogenic FLT3- and c-Kit-mediated cell proliferation, but not to cell survival. Thus, the results indicate that CSK association with type III RTKs, FLT3 and c-Kit can have differential impact on receptor downstream signaling

Distinct roles of the Src family kinases, SRC-1 and KIN-22, that are negatively regulated by CSK-1 in C. elegans

AbstractTo elucidate the primitive roles of the Src family kinases (SFKs), here we characterized Caenorhabditis elegans orthologues of SFKs (src-1 and kin-22) and their regulator kinase Csk (csk-1). SRC-1 and KIN-22 possess the C-terminal regulatory tyrosines characteristic of SFKs, and their activities are negatively regulated by CSK-1 in a yeast expression system. The src-1 and csk-1 genes are co-expressed in some head neurons, the anchor cell and the tail region, while kin-22 and csk-1 genes are co-expressed in pharyngeal muscles and tail region. Expression of KIN-22 induced morphological defects in the pharynx, whereas expression of SRC-1 did not show any overt phenotype in adult. RNA interference of src-1, but not that of kin-22, caused a developmental arrest in early development. These results suggest that SRC-1 and KIN-22 play distinct roles under the control of CSK-1

Regulation, targets and functions of CSK.

The Src family kinases (SFK) plays an important role in multiple signal transduction pathways. Aberrant activation of SFKs leads to diseases such as cancer, blood disorders, and bone pathologies. By phosphorylating and inactivating SFKs, the C-terminal Src kinase (CSK) serves as the key negative regulator of SFKs. Similar to Src, CSK is composed of SH3, SH2, and a catalytic kinase domain. However, while the Src kinase domain is intrinsically active, the CSK kinase domain is intrinsically inactive. Multiple lines of evidence indicate that CSK is involved in various physiological processes including DNA repair, permeability of intestinal epithelial cells (IECs), synaptic activity, astrocyte-to-neuron communication, erythropoiesis, platelet homeostasis, mast cell activation, immune and inflammation responses. As a result, dysregulation of CSK may lead to many diseases with different underlying molecular mechanisms. Furthermore, recent findings suggest that in addition to the well-established CSK-SFK axis, novel CSK-related targets and modes of CSK regulation also exist. This review focuses on the recent progress in this field for an up-to-date understanding of CSK

Pre-eclampsia is associated with a twofold increase in diabetes : a systematic review and meta-analysis

CSK and RH are funded by National Institute for Health Research Academic Clinical Fellowships. This study was supported by a grant from the North Staffs Heart Committee.Peer reviewedPublisher PD

Protein tyrosine phosphatase non-receptor 22 and C-Src tyrosine kinase genes are down-regulated in patients with rheumatoid arthritis

Several protein tyrosine phosphatase non-receptor 22 (PTPN22) single-nucleotide polymorphisms (SNPs) have been significantly related with rheumatoid arthritis (RA) susceptibility. Nevertheless, its potential influence on PTPN22 expression in RA has not been completely elucidated. Furthermore, PTPN22 binds to C-Src tyrosine kinase (CSK) forming a key complex in autoimmunity. However, the information of CSK gene in RA is scarce. In this study, we analyzed the relative PTPN22 and CSK expression in peripheral blood from 89 RA patients and 43 controls to determine if the most relevant PTPN22 (rs2488457, rs2476601 and rs33996649) and CSK (rs34933034 and rs1378942) polymorphisms may influence on PTPN22 and CSK expression in RA. The association between PTPN22 and CSK expression in RA patients and their clinical characteristics was also evaluated. Our study shows for the first time a marked down-regulation of PTPN22 expression in RA patients carrying the risk alleles of PTPN22 rs2488457 and rs2476601 compared to controls (p?=?0.004 and p?=?0.007, respectively). Furthermore, CSK expression was significantly lower in RA patients than in controls (p?<?0.0001). Interestingly, a reduced PTPN22 expression was disclosed in RA patients with ischemic heart disease (p?=?0.009). The transcriptional suppression of this PTPN22/CSK complex may have a noteworthy clinical relevance in RA patients