Regulation of G protein signaling by G protein alpha subunit phosphorylation

Regulation of G protein signaling by G protein alpha subunit phosphorylation Public Deposited

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Creator

Clement, Sarah
- Affiliation: School of Medicine, Department of Biochemistry and Biophysics

Abstract

Cells respond to stimuli by detecting extracellular signals in complex environments through cell membrane protein receptors. G protein coupled receptors (GPCRs) comprise the largest family of plasma membrane receptors and transduce signals from an array of stimuli including light, odors, hormones and neurotransmitters. GPCR-mediated pathways are important in many physiological functions and are targeted by numerous pharmaceuticals. Thus a comprehensive understanding of the regulation of GPCR-mediated pathway components is necessary to achieve full therapeutic effectiveness and discover new drug targets. This work examines how GPCR-mediated signaling pathways are modulated in the context of changes in the cell-cycle and changes in nutrient availability. In this thesis, we present studies to identify new regulators of G protein signaling. Specifically, we show that the G protein alpha subunit, Gpa1, is phosphorylated and degraded in a cell-cycle dependent manner. In addition, we demonstrate that Gpa1 is phosphorylated in a low glucose-dependent manner, which leads to a reduction in signal transduction. These findings reveal new regulatory and cross talk functions in signal transduction pathways. Furthermore, the work in this thesis has expanded our understanding of G protein signaling networks and the mechanisms by which concurrent signals are prioritized and coordinated.

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