Seminar – J. Benita Sjorgren, PhD

G protein-coupled receptors (GPCRs) represent the largest family of receptors and are important drug targets with 40-60% of currently FDA approved drugs targeting the receptors themselves or downstream mechanisms. One important regulatory mechanism of G protein signaling is mediated through a family of GTPase accelerating proteins, Regulator of G protein Signaling (RGS) proteins. RGS proteins modulate GPCR signaling by binding to and accelerating GTP hydrolysis on active Ga subunits of heterotrimeric G proteins. This results in attenuation of duration and amplitude of GPCR signaling. The majority of the more than 20 RGS proteins identified to date also possess additional functions not related to their canonical effect on G proteins. In the past 25 years, RGS proteins have emerged as novel drug targets in numerous disease states, such as hypertension, cancer and Parkinson disease among others. RGS proteins are tightly regulated through transcriptional, epigenetic and posttranslational mechanisms, such as degradation through the ubiquitin-proteasomal pathway. Furthermore, expression of RGS proteins is often altered during pathogenesis, causing dysregulation in GPCR signaling, that can cause or worsen the disease. Thus, the work in our lab is focused on two central questions; 1) To understand the mechanisms by which levels and function of RGS proteins are regulated and; 2) How the knowledge of these mechanisms can be applied in drug discovery.

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