Uncovering the pharmacology of the G protein-coupled receptor GPR40: high apparent constitutive activity in guanosine 5'-O-(3-[35S]thio)triphosphate binding studies reflects binding of an endogenous agonist.

In cells lacking expression of Ca(2+)-mobilizing G proteins, coexpression of human GPR40 and Galpha(q) allowed medium- and long-chain fatty acids to elevate intracellular [Ca(2+)]. This was also observed when human embryonic kidney (HEK) 293 cells were transfected with a GPR40-Galpha(q) fusion protein. The kinetic of elevation of intracellular [Ca(2+)] slowed with increasing fatty acid chain length, suggesting different ligand on-rates, whereas the addition of fatty acid-free bovine serum albumin reduced signals, presumably by binding the fatty acids.

Computational methodologies for modelling, analysis and simulation of signalling networks.

This article is a critical review of computational techniques used to model, analyse and simulate signalling networks. We propose a conceptual framework, and discuss the role of signalling networks in three major areas: signal transduction, cellular rhythms and cell-to-cell communication. In order to avoid an overly abstract and general discussion, we focus on three case studies in the areas of receptor signalling and kinase cascades, cell-cycle regulation and wound healing.