Kendall J. Blumer

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A general property of signal transduction pathways is that prolonged stimulation decreases responsiveness, a phenomenon termed desensitization. Yeast cells stimulated with mating pheromone activate a heterotrimeric G-protein-linked, MAP-kinase-dependent signalling pathway that induces G1-phase cell-cycle arrest and morphological differentiation (reviewed in(More)
RGS (regulators of G protein signaling) proteins are GTPase activating proteins that inhibit signaling by heterotrimeric G proteins. All RGS proteins studied to date act on members of the Gialpha family, but not Gsalpha or G12alpha. RGS4 regulates Gialpha family members and Gqalpha. RGS2 (G0S8) is exceptional because the G proteins it regulates have not(More)
Mitogen-activated protein kinases (MAPKs) are rapidly phosphorylated and activated in response to various extracellular stimuli in many different cell types. Such regulation of MAPK results from sequential activation of a series of protein kinases. The kinases that phosphorylate MAPKs, the MAP kinase kinases (MEKs) are also activated by phosphorylation.(More)
Signaling pathways using heterotrimeric guanine-nucleotide-binding-proteins (G proteins) trigger physiological responses elicited by hormones, neurotransmitters and sensory stimuli. GTP binding activates G proteins by dissociating G alpha from G beta gamma subunits, and GTP hydrolysis by G alpha subunits deactivates G proteins by allowing heterotrimers to(More)
The alpha-factor receptor is rapidly hyperphosphorylated on Thr and Ser residues in its hydrophilic C-terminal domain after cells are exposed to pheromone. Mutant receptors in which this domain is altered or removed are biologically active and bind alpha-factor with nearly normal affinity. However, cells expressing the mutant receptors are hypersensitive to(More)
Signaling by hormones and neurotransmitters that activate G protein-coupled receptors (GPCRs) maintains blood pressure within the normal range despite large changes in cardiac output that can occur within seconds. This implies that blood pressure regulation requires precise kinetic control of GPCR signaling. To test this hypothesis, we analyzed mice(More)
The RGS7 (R7) family of RGS proteins bound to the divergent Gbeta subunit Gbeta5 is a crucial regulator of G protein-coupled receptor (GPCR) signaling in the visual and nervous systems. Here, we identify R7BP, a novel neuronally expressed protein that binds R7-Gbeta5 complexes and shuttles them between the plasma membrane and nucleus. Regional expression of(More)
Nitric oxide (NO) inhibits vascular contraction by activating cGMP-dependent protein kinase I-alpha (PKGI-alpha), which causes dephosphorylation of myosin light chain (MLC) and vascular smooth muscle relaxation. Here we show that PKGI-alpha attenuates signaling by the thrombin receptor protease-activated receptor-1 (PAR-1) through direct activation of(More)
Eukaryotic cells from yeast to humans use sequential protein kinase reactions to regulate complex cellular functions. Equivalent protein kinases in different pathways have significant sequence homologies; however, little crossover in phosphorylation of substrates between pathways normally occurs. Assembly of kinase complexes and discrimination of substrates(More)