Mechanistic Study Of Potassium Ion Uptake In Saccharomyces Cerevisiae Cells On Copper-iron Metabolism And Cell Growth

Metal ions exist in many living bodies and they play a very important role in our lives.About one third of the proteins in the organism need to bind metal ions to perform its intended function effectively.Diverse biological pathways,including energy generation,neurotransmission,signal transduction,nutrient transport,p H and osmotic potential maintenance depend on ionic concentration gradients across the membranes and metal-containing proteins.Organisms have evolved delicate mechanisms for uptake,distribution,utilization and detoxification of such ions.Defect in homeostasis of these species is implicated in numerous disorders.However,nowadays,due to the rapid development of society,environmental pollution has become more and more serious.According to the report,50%of the water resources in China are contaminated with heavy metal ions,and the heavy metal-polluted land in China exceeds 300 million yl,which is more than 1/6 of the total cultivated land.12 million tons of grains are contaminated by heavy metals each year,that causes us losing up to more than 200 billion yuan.Heavy metal ion pollution has also directly led to an increasing number of patients suffering from heavy metal ion-related diseases in China.Therefore,it is trmendously important to study the mechanism of metal ion metabolism for making a research on life itself,clarifying the mechanism of diseases and treatments and solving environmental pollution,etc.In this study,we started from the yeast cell of Saccharomyces cerevisiae,according to the paper which tell us that Kha1,the K~+/H~+antiporter regulates copper and ion metabolism,we focused on the potassium transporter Trk1p and Trk2p which are on the plsama membrane and try to study the growth phenotype of cells and copper and iron metabolism under potassium deficiency condition.Then,we also found that the ubiquitin E3 ligase,Rsp5,plays an important role in the growth of the Trk1?/Trk2?strain and effects of potassium absorption on copper and iron metabolism and cell growth in Saccharomyces cerevisiae.Under the deficiency of potassium,Rsp5somehow can not fully play its role,it can not recruit and identify the glucose transporter Hxt1 on the cell plasma membrane,resulting in a large number of Hxt1 accumulation on the cell membrane and let excess glucose transport into the cell and causes the cell glucose toxicity and unable to grow.The entire study taught us the importance of potassium ions for cell growth and also the mechanism by which Saccharomyces cerevisiae cells cannot grow in the absence of potassium ions.Meanwhile,because of Rsp5p regulating Hxt1p,it is also helpful to prepare for the future study of the same family of Hxt1p in mammals to regulate the uptake of glucose of cells and even diabetes.