The G-protein coupled bile salt receptor TGR5 is expressed in liver sinusoidal endothelial cells.

Unlabelled: Sinusoidal endothelial cells (SEC) constitute a permeable barrier between hepatocytes and blood. SEC are exposed to high concentrations of bile salts from the enterohepatic circulation. Whether SEC are responsive to bile salts is unknown.

The vesicular stomatitis virus matrix protein inhibits glycoprotein 130-dependent STAT activation.

Infection of cells by vesicular stomatitis virus (VSV) results in the inhibition of host transcription. We show in this study that infection of HeLa cells with VSV leads to a strongly diminished activation of STAT3 and STAT1 by the inflammatory cytokine IL-6. This effect was mimicked by forced expression of a single viral protein, the matrix (M)-protein of VSV, which blocked STAT activation via chimeric receptors containing the cytoplasmic domain of the IL-6 signal transducer gp130.

In vitro-generated stem cell leukaemia showing altered cell cycle progression with distinct signalling of the tyrosine-phosphorylated rasGAP-associated p62(dok) protein.

In an attempt to gain more insight into the events of leukaemic transformation, a cell line overexpressing MHC class II (DR) was generated by transfecting an early CD34-negative haematopoietic progenitor stem cell line with the appropriate constructs. The stable transfection with genes for DR antigens leads to cellular transformation. The DR(+) transformed cell clones express a tyrosine-phosphorylated DR heterodimer and show a significantly different morphology.

Quiescence of CD34-negative haematopoietic stem cells is mediated by downregulation of Cyclin B and no stat activation.

The CD34-negative, adherent growing, fibroblast-like canine haematopoietic stem cell line D064 was recently identified as the earliest progenitor population in the bone marrow. D064 cells are predominately quiescent. Quiescence is mediated by the accumulation of the cyclin-dependent kinase inhibitor p27(kip-1)and in parallel, by the downregulation of Cyclin B, leading to an accumulation of quiescent cells in the G(0)/G(1)-phase of the cell cycle.

Differential inhibition of IL-6-type cytokine-induced STAT activation by PMA.

Prior activation of mitogen-activated protein kinases by phorbol 13-myristate 12-acetate (PMA) results in an inhibition of interleukin (IL)-6-induced activation of the Janus kinase/signal transducer and activator of transcription (STAT) signaling pathway which is most likely mediated by the induction of suppressor of cytokine signaling-3 and requires the specific SHP2 binding site Y759 of the IL-6 signal transducer gp130. In this study, we demonstrate that PMA inhibits STAT activation by IL-6 and the related cytokine leukemia inhibitory factor (LIF) but not by oncostatin M (OSM). Since the LIF receptor also contains an SHP2 recruitment site whereas the OSM receptor lacks such a module, we propose that two SHP2 binding modules within a homo- or heterodimeric receptor are necessary to mediate the PMA inhibitory effect.