Joanna Kwiatek

Joanna Kwiatek
Rutgers, The State University of New Jersey | Rutgers · IFNH

Doctor of Philosophy
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About

19
Publications
8,768
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248
Citations
Introduction
My scientific interest includes biochemical and biophysical aspects of lipid metabolism. My research enables me to investigate lipids organization on the molecular and cellular levels as well as their interaction with proteins. Results acquired by biochemical approaches enable me to understand the premier step of the phospholipid synthesis pathway on a molecular level. Additionally, my biophysical studies revealed detailed descriptions of lipid and lipid-protein organization in plasma membrane.

Publications

Publications (19)
Article
Full-text available
Pah1 phosphatidate (PA) phosphatase plays a major role in triacylglycerol synthesis in Saccharomyces cerevisiae by producing its precursor diacylglycerol, and concurrently regulates de novo phospholipid synthesis by consuming its precursor PA. The function of Pah1 requires its membrane localization, which is controlled by its phosphorylation state....
Article
Full-text available
The Saccharomyces cerevisiae PAH1-encoded phosphatidate (PA) phosphatase, which catalyzes the dephosphorylation of PA to produce diacylglycerol, controls the bifurcation of PA into triacylglycerol synthesis and phospholipid synthesis. Pah1 is inactive in the cytosol as a phosphorylated form and becomes active on the membrane as a dephosphorylated f...
Article
Full-text available
Phosphatidic acid (PA) phosphatase, encoded by PAH1 in the yeast Saccharomyces cerevisiae , catalyzes the Mg ²⁺ -dependent dephosphorylation of PA, producing diacylglycerol at the nuclear/endoplasmic reticulum (ER) membrane. This enzyme plays a major role in triacylglycerol synthesis and in the regulation of phospholipid synthesis. As an interfacia...
Article
In yeast and higher eukaryotes, phospholipids and triacylglycerol are derived from phosphatidate at the nuclear/endoplasmic reticulum membrane. In de novo biosynthetic pathways, phosphatidate is channeled into membrane phospholipids via its conversion to CDP-diacylglycerol. Its dephosphorylation to diacylglycerol is required for the synthesis of tr...
Article
Full-text available
The mammalian lipin 1 phosphatidate phosphatase is a key regulatory enzyme in lipid metabolism. By catalyzing phosphatidate dephosphorylation, which produces diacylglycerol, the enzyme plays a major role in the synthesis of triacylglycerol and membrane phospholipids. The importance of lipin 1 to lipid metabolism is exemplified by cellular defects a...
Article
Full-text available
Membrane viscosity and hydration levels characterize the biophysical properties of biological membranes and are reflected in the rate and extent of solvent relaxation, respectively, of environmentally sensitive fluorophores such as Laurdan. Here, we first developed a method for a time-resolved general polarization (GP) analysis with fluorescence-li...
Article
Full-text available
The coexistence of lipid domains with different degrees of lipid packing in the plasma membrane of mammalian cells has been postulated, but direct evidence has so far been challenging to obtain because of the small size and short lifetime of these domains in live cells. Here, we use fluorescence spectral correlation spectroscopy in conjunction with...
Article
Full-text available
Clustering of the T-cell receptor (TCR) is thought to initiate downstream signalling. However, the detection of protein clustering with high spatial and temporal resolution remains challenging. Here we establish a Förster resonance energy transfer (FRET) sensor, named CliF, which reports intermolecular associations of neighbouring proteins in live...
Data
Supplementary Figures, Supplementary Table, Supplementary Note and Supplementary References
Data
Light induced clustering of CY2PHR-CliF in transfected COS-7 cells. The movie is produced from the merged image series of donor (green) acceptor (red) by 488 nm light irradiation at frame rate of 1 frame/s.
Article
Full-text available
Abstract Compartmentalization is a functionally important property of the plasma membrane, yet the underlying principles that organize membrane proteins into distinct domains are not well understood. Using single molecule localization microscopy, we assessed the clustering of five model membrane proteins in the plasma membrane of HeLa cells. All fi...
Article
Full-text available
The structure of cell membranes has been intensively investigated and many models and concepts have been proposed for the lateral organization of the plasma membrane. While proteomics and lipidomics have identified many if not all membrane components, how lipids and proteins interactions are coordinated in a specific cell function remains poorly un...
Article
Full-text available
Visualization and quantification of lipid order is an important tool in membrane biophysics and cell biology, but the availability of environmentally sensitive fluorescent membrane probes is limited. Here, we present the characterization of the novel fluorescent dyes PY3304, PY3174 and PY3184, whose fluorescence properties are sensitive to membrane...
Article
Full-text available
Occludin (Ocln), a MARVEL-motif-containing protein, is found in all tight junctions. MARVEL motifs are comprised of four transmembrane helices associated with the localization to or formation of diverse membrane subdomains by interacting with the proximal lipid environment. The functions of the Ocln MARVEL motif are unknown. Bioinformatics sequence...

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Project (1)
Project
The major goal of my postdoctoral project is to investigate the interaction of the Pah1 PAP, with phospholipid membranes. To achieve this goal I established and optimized the assay which employs liposomes to mimic biological membranes. Liposomes composed of various phospholipids and sizes are mimicking the composition and curvature of natural membranes, respectively. The application of the liposome model system allowed me to systematically measure PAP activity during its interaction with the PA incorporated into the liposomes. I found that Pah1 PAP activity was dependent on the bulk and surface concentrations of PA. This important result implicates that the enzyme operates in the hopping and scooting mode along the nuclear/ER membrane in vivo, which bring a potential explanation for the enzyme distribution in the cell membranes.