Publications by authors named "George McConnachie"

A fast track "Hot Start" process was implemented to launch the European Bank for Induced Pluripotent Stem Cells (EBiSC) to provide early release of a range of established control and disease linked human induced pluripotent stem cell (hiPSC) lines. Established practice amongst consortium members was surveyed to arrive at harmonised and publically accessible Standard Operations Procedures (SOPs) for tissue procurement, bio-sample tracking, iPSC expansion, cryopreservation, qualification and distribution to the research community. These were implemented to create a quality managed foundational collection of lines and associated data made available for distribution.

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Localization of cyclic AMP (cAMP)-dependent protein kinase (PKA) by A kinase-anchoring proteins (AKAPs) restricts the action of this broad specificity kinase. The high-resolution crystal structures of the docking and dimerization (D/D) domain of the RIIalpha regulatory subunit of PKA both in the apo state and in complex with the high-affinity anchoring peptide AKAP-IS explain the molecular basis for AKAP-regulatory subunit recognition. AKAP-IS folds into an amphipathic alpha helix that engages an essentially preformed shallow groove on the surface of the RII dimer D/D domains.

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Subcellular compartmentalization of protein kinases and phosphatases through their interaction with A-kinase anchoring proteins (AKAPs) provides a mechanism to control signal transduction events at specific sites within the cell. Recent findings suggest that these anchoring proteins dynamically assemble different cAMP effectors to control the cellular actions of cAMP spatially and temporally. In the heart, signaling events such as the onset of cardiac hypertrophy are influenced by muscle-specific mAKAP signaling complexes that target protein kinase A (PKA), the cAMP-responsive guanine-nucleotide exchange factor EPAC and cAMP-selective phosphodiesterase 4 (PDE4).

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PKA (protein kinase A) is tethered to subcellular compartments by direct interaction of its regulatory subunits (RI or RII) with AKAPs (A kinase-anchoring proteins). AKAPs preferentially bind RII subunits via their RII-binding domains. RII-binding domains form structurally conserved amphipathic helices with unrelated sequences.

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The transmission of cellular signals often proceeds through multiprotein complexes where enzymes are positioned in proximity to their upstream activators and downstream substrates. In this report we demonstrate that the A-kinase anchoring protein AKAP-Lbc assembles an activation complex for the lipid-dependent enzyme protein kinase D (PKD). Using a combination of biochemical, enzymatic, and immunofluorescence techniques, we show that the anchoring protein contributes to PKD activation in two ways: it recruits an upstream kinase PKCeta and coordinates PKA phosphorylation events that release activated protein kinase D.

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We investigated the kinetic behaviour and substrate specificity of PTEN (phosphatase and tensin homologue deleted on chromosome 10) using unilamellar vesicles containing substrate lipids in a background of phosphatidylcholine. PTEN displays the characteristics expected of an interfacial enzyme, since the rate of enzyme activity is dependent on the surface concentration of the substrate lipids used (mol fraction), as well as the bulk concentration. Surface-dilution analysis revealed the catalytic efficiency of PTEN for PtdIns(3,4,5) P (3) to be 200-fold greater than for either PtdIns(3,4) P (2) or PtdIns(3,5) P (2), and 1000-fold greater than for PtdIns3 P.

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