“Influence of PIP2 on IDE and UCP2 in RIN‐5F Cells”

Abstract

Phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P2) is present on the plasma membrane of cells and is the precursor to inositol 1,4,5‐trisphosphate (IP3) and diacylglycerol (DAG). Although PI(4,5)P2 has traditionally been considered the substrate for phosphatidylinositol 3‐kinase (PI3Kinase) or phospholipase C (PLC), PI(4,5)P2 has recently been shown to bind Insulin Degrading Enzyme (IDE). IDE is a cytosolic protein that has been shown to be anchored by PI(4,5)P2 until it is ready to perform its function as a protease. IDE serves as a protease for several proteins including insulin and amylin. Insulin and amylin are two proteins that are co‐secreted from pancreatic β cells after a rise in cellular glucose levels. The degradation of insulin and amylin occur by IDE after the two proteins have completed respective actions, most notably the lowering of glucose levels and the increase in satiety. A rise in glucose is known to lead to a rise in insulin and amylin levels in order to maintain metabolic homeostasis. Uncoupling Protein 2 (UCP2) is a mitochondrial membrane protein that is known for its impact on the oxidative phosphorylation process. The presence of UCP2 on pancreatic β cells has previously been shown to have an inverse relationship with insulin. Here we conducted IDE, amylin, and UCP2 ELISA assays before and after inhibition of PLC or PI3Kinase under varying concentrations of glucose in RIN5F cells, which is a rat pancreatic β cell line, in order to investigate the impact of IDE on the activity level of amylin and UCP2 and to establish a possible relationship between amylin and UCP2. In this study, we measured IDE, amylin and UCP2 levels with the PLC inhibitor, U73122, and PI3kinase inhibitor, wortmannin, in comparison to the negative controls. The initial data shows that a decrease in IDE occurs in the presence of the inhibitor and suggests a possible link between IDE, UCP2, and amylin.Support or Funding InformationNational Science Foundation Research Initiation Award# 24430This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.