The second identified substrate of PAS kinase discussed is Pbp1. The human homolog of Pbp1 is ataxin-2, mutations in which are a known risk factor for amyotrophic lateral sclerosis (ALS). As diet and sex have been shown to be important factors regarding PAS kinase function, they also are strong contributing factors to ALS and are extensively reviewed herein. Pbp1 is known to be sequestered by PAS kinase under glucose depravation, and it can sequester additional proteins along with it to regulate different cellular pathways. To shed light on the pathways affected by Pbp1, we performed a yeast two-hybrid assay and mass spectrometry, identifying 32 novel interacting partners of Pbp1 (ataxin-2). We provide further analysis of the direct binding partner Ptc6, measuring mitophagy, mitochondrial content, colocalization, and respiration. This work elucidates novel molecular mechanisms behind the function of PAS kinase and yields valuable insights into the role of PAS kinase in disease.

The protein Ataxin-2 is a known positive regulator of stress granules in humans, mice and yeast (known as yeast PBP1). Due to the role that stress granules play in diseases including Amyotrophic Lateral Sclerosis (ALS) and cancer, this thesis investigates the role of Ataxin-2 and its protein binding partners in stress granule development and its effects on various metabolic phenotypes of the cell. PAS kinase is a sensory protein kinase, conserved from yeast to man, which regulates respiration and lipid biosynthesis. Our lab discovered that PAS kinase phosphorylates and activates Ataxin-2 in yeast, and that PAS kinase overexpression enhances localization of Ataxin-2 to stress granules. Our preliminary results from yeast show that PAS kinase positively regulates stress granule formation in response to metabolic stress. Ataxin-2 normally functions to promote stress granule formation and it has been specifically shown to sequester and inhibit mammalian target of rapamycin complex I (mTORC1), a major player in the regulation of cell growth, to stress granules in both yeast and mammalian cells. To build upon this knowledge we performed a large-scale yeast interactome to identify Pbp1 binding partners through yeast-two hybrid and mass spectrometry. We identified 32 novel putative binding partners. A protein of note was Ptc6, a known regulator of mitophagy with human homolog PPM1K, which is not known to be involved in stress granules. Through colocalization with Ppb1 we determined that Ptc6 is sequestered to stress granules under glucose depravation. Under Pbp1 overexpression, Ptc6 was shown to increase localization to a stress granule marker, Pab1, showing that Pbp1 may be actively promoting Ptc6 to stress granules. We investigated the effects of eliminating Pbp1 and Ptc6 in yeast cells, including on mitophagy, mitochondrial quantification, whole cell respiration and mitochondrial reactive oxidative species. In a separate project, due to the outbreak of a worldwide pandemic and early concerns that currency could be a potential SARS-CoV-2 fomite, we investigated whether the virus could survive on varying types of currency. We conducted environmental studies and found no viable virus on bank notes or money cards. In vitro studies with live virus suggested SARS-CoV-2 was highly unstable on banknotes, however SARS-CoV-2 displayed increased stability on money cards with live virus detected after 48 hours.