Document Type

Thesis

Degree

Master of Science

Major

Biochemistry & Biotechnology

Date of Defense

11-20-2009

Graduate Advisor

Wendy M. Olivas, PhD

Co-Advisor

Dr Colin MacDiarmid

Committee

Dr Wendy Olivas

Dr Lisa Schechter

Abstract

Magnesium is required for many essential processes and pathways, including protein synthesis and energy metabolism. In the yeast Saccharomyces cerevisiae, Mg2+ uptake across the plasma membrane primarily occurs via the magnesium transporter Alr1. Preliminary data had shown that Alr1-HA accumulation was decreased by Mg. Here I show that the epitope tag was responsible for this differential accumulation of Alr1, as native or N-terminally tagged Alr1 displayed much less differential accumulation. Immunoblotting and Ni2+ uptake assays indicated that both Mg-deficiency and the mnr2 mutation increased Alr1 activity, but under conditions where native protein accumulation was little affected. Since Mg-dependent regulation of Alr system activity and Alr1 protein accumulation did not correlate, I investigated the importance of the post-translational modification of Alr1 to regulation. These studies suggested that the post-translational modification of Alr1 and the C-terminal domain of the protein may be important for regulation.

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