Phosphoinositide Quantification
Phosphoinositide Quantification - Related Videos
10:52
Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation
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Cited by 21 •
2016
Phosphoinositides are signaling lipids whose relative abundance rapidly changes in response to various stimuli. This article describes a method to measure the abundance of phosphoinositides by metabolically labeling cells with 3H-myo-inositol, followed by extraction and deacylation. Extracted glycero-inositides are then separated by high-performance liquid chromatography and quantified by flow scintillation.
01:42
Phosphoinositides and PIPs
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2023
Phosphoinositides are a group of phospholipids containing a glycerol backbone with two fatty acid chains and a phosphate attached to a myoinositol sugar ring. The inositol head group extends into the cytoplasm, where it is modified by adding phosphate groups to form phosphatidylinositol phosphates or PIPs. Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
10:58
PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions
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Cited by 7 •
2017
Here we present a supported lipid bilayer in the context of a microfluidic platform to study protein-phosphoinositide interactions using a label-free method based on pH modulation.
06:23
pH Modulation Assay on Supported Lipid Bilayers to Detect Protein-Phosphoinositide Interactions
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2025
In this video, we demonstrate protein-phosphoinositide interactions in a microfluidic pattern using the pH modulation assay, using pH-sensitive fluorescent dye tagged to phosphatidylethanolamine lipid of a supported lipid bilayer, called a microfluidic platform. The modulations in pH after protein binding to phospholipid cause fluorescence quenching.
08:44
Invertebrate Lifespan Quantification
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2023
Many animals naturally stop growing upon reaching adulthood, after which they undergo aging or "senescence" until dying. The amount of time between an organism\'s birth and death is called its lifespan, which can be influenced by various biological and environmental factors. By exposing organisms to different growth conditions, scientists can better understand the factors affecting lifespan. Flies and worms are ideal organisms to perform such experiments, given their short generation time and...
FAQs
Liquid chromatography first separates lipid molecules, while mass spectrometry detects their chemical signals. This combined approach can resolve phosphoinositides that differ in phosphorylation state or acyl-chain composition, rather than treating all phosphorylated phosphatidylinositols as one pool. The resulting measurements provide a more detailed picture of membrane composition and the chemical changes associated with signaling.
Internal standards provide a reference for converting mass-spectrometry signal intensity into the amount of each lipid species. Comparing sample signals with these standards supports quantitative rather than purely qualitative analysis. This is important when the goal is to assess changes in individual phosphoinositides, compare biological samples, or evaluate patterns consistent with altered kinase or phosphatase activity.
Phosphorylation state indicates chemical differences among related phosphoinositides, while acyl-chain composition distinguishes lipid species with otherwise similar structures. Measuring both features gives a more resolved profile than reporting a single total phosphoinositide value. In chemistry-focused studies, this detail helps connect membrane lipid composition with signaling changes, trafficking processes, or disease-associated dysregulation.
Rapid quenching is an important control because the sample must be stabilized before its lipids are extracted and measured. Without prompt handling, the composition observed by analysis may not accurately represent the biological sample at collection. Preserving the sample before extraction therefore supports more reliable comparisons of phosphoinositide amounts and phosphorylation patterns across conditions.
A typical workflow begins by rapidly quenching cells or tissues, followed by lipid extraction from the biological material. The extracted lipids are separated by liquid chromatography and detected with mass spectrometry. Internal standards then support conversion of measured signal intensities into amounts for individual species, enabling comparisons of phosphoinositide composition between samples or experimental conditions.
This analysis is useful when researchers need to examine membrane trafficking, signal transduction, or the activities of lipid kinases and phosphatases. Because it measures individual species rather than only a broad lipid class, the method can reveal specific compositional changes associated with these processes. It can also support investigations of lipid dysregulation linked to disease.
Measured amounts of individual phosphoinositides provide chemical evidence about shifts in membrane lipid composition. Comparing species and their phosphorylation states can indicate patterns associated with kinase or phosphatase activity, while changes in acyl-chain profiles add compositional detail. These outcomes help connect molecular lipid measurements with membrane trafficking, signal-transduction behavior, or disease-related alterations.