Publications by authors named "G Moehren"
Signal processing at the Ras circuit: what shapes Ras activation patterns?
Syst Biol (Stevenage)
June 2004
A systems biology approach is applied to gain a quantitative understanding of the integration of signalling by the small GTPase Ras. The Ras protein acts as a critical switch in response to signals that determine the cell's fate. In unstimulated cells, Ras switching between an inactive GDP-binding and active GTP-binding state is controlled by the intrinsic catalytic activities of Ras.
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- IGF-I is important for cell cycle progression and survival, but it shows minimal binding to hepatocytes, leaving its role in their signaling unclear.
- Des(1-3)IGF-I can activate IGF-IR phosphorylation despite IGF-I's inactivity, and confocal microscopy confirmed the presence of IGFBP-3 on the hepatocyte surface.
- EGF activates IGF-IR through a transactivation pathway involving Src kinases, demonstrating that EGF influences IGF-IR signaling and revealing a potential inhibitory effect of IGFBP-3 on IGF-I signaling in hepatocytes.
Stimulation of isolated hepatocytes with epidermal growth factor (EGF) causes rapid tyrosine phosphorylation of the EGF receptor (EGFR) and adapter/target proteins, which was monitored with 1 and 2 s resolution at 37, 20, and 4 degrees C. The temporal responses detected for multiple signaling proteins involve both transient and sustained phosphorylation patterns, which change dramatically at low temperatures. To account quantitatively for complex responses, we employed a mechanistic kinetic model of the EGFR pathway, formulated in molecular terms as cascades of protein interactions and phosphorylation and dephosphorylation reactions.
View Article and Find Full Text PDFDuring the past decade, our knowledge of molecular mechanisms involved in growth factor signaling has proliferated almost explosively. However, the kinetics and control of information transfer through signaling networks remain poorly understood. This paper combines experimental kinetic analysis and computational modeling of the short term pattern of cellular responses to epidermal growth factor (EGF) in isolated hepatocytes.
View Article and Find Full Text PDFBackground & Aims: Long-term ethanol intake suppresses liver regeneration in vivo and ethanol interferes with epidermal growth factor (EGF)-induced DNA synthesis in vitro. Therefore, the effects of long-term ethanol treatment on EGF-activated signaling reactions in rat hepatocytes were investigated.
Methods: Hepatocytes from long-term ethanol-fed rats and pair-fed controls were stimulated with EGF (0.