Authors:

Alex James Alonzo

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About Paper:

The plasma membrane (PM) serves as the barrier between cellular components and the local environment. Composed primarily of phospholipids, the PM is a complex reaction landscape for interactions between proteins, sugars, small molecules, and lipids, and coordinates conversion of stimuli into intracellular responses. Phosphatidylinositol phosphate (PIPs) lipids profoundly impact cellular signaling outcomes despite comprising less than 2 percent of all PM lipids. Unique PIP identities, determined by location and number of phosphate groups, are regulated by enzymes. Dysregulation in pathways involving PIPs is recognized to contribute to many disease states, such as cancer. In such pathways, PIPs can act as either protein activators or substrates, and are constantly engaged, interconverted, and depleted at unknown rates. A fundamental understanding of the distributions and dynamics of PIPs, and their alterations in disease, remains limited due to a scarcity of tools to detect PIPs without altering their normal behaviors. Oncogenic mutations frequently occur in the small GTPase Ras, whose signaling is modulated by PI(4,5)P2 lipid levels. We hypothesize that Ras mutations will affect the distribution of PIPs in the PM. We utilize a novel, peptide-based sensor to quantify absolute densities of PI(4,5)P2 lipids in model and PMs of mouse embryonic fibroblast (MEF) cells with unique Ras mutations. These measurements are supported by an orthogonal colorimetric biochemical assay that measures phosphate content in lipid samples. Our work is poised to illuminate the relationship between PIP distribution and disease states, leading to diagnostic characteristics of cellular fitness. Keywords: Phosphoinositide; PI(4,5)P2; RAS; Cancer; TIRF

Source:

Purdue University / 2024

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No topics listed

Co-authors:

Alex James Alonzo