Jennifer Lippincott-Schwartz | |
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Born | Jennifer Lippincott October 19, 1952 Manhattan, Kansas |
Alma mater | |
Spouse | Jonathan Schwartz |
Scientific career | |
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Jennifer Lippincott-Schwartz is a Senior Group Leader at Howard Hughes Medical Institute's Janelia Research Campus and a founding member of the Neuronal Cell Biology Program at Janelia. [1] Previously, she was the Chief of the Section on Organelle Biology in the Cell Biology and Metabolism Program, in the Division of Intramural Research in the Eunice Kennedy Shriver National Institute of Child Health and Human Development at the National Institutes of Health from 1993 to 2016. Lippincott-Schwartz received her PhD from Johns Hopkins University, and performed post-doctoral training with Richard Klausner at the NICHD, NIH in Bethesda, Maryland. [2]
Lippincott-Schwartz's research revealed that the organelles of eukaryotic cells are dynamic, self-organized structures that constantly regenerate themselves through intracellular vesicle traffic, rather than static structures. [2] [3] She is also a pioneer in developing live cell imaging techniques to study the dynamic interactions of molecules in cells, including photobleaching and photoactivation [4] techniques which allow investigation of subcellular localization, mobility, transport routes, and turnover of important cellular proteins related to membrane trafficking and compartmentalization. Lippincott-Schwartz's lab also tests mechanistic hypotheses related to protein and organelle functions and dynamics by utilizing quantitative measurements through kinetic modeling and simulation experiments. [5] Along with Craig Blackstone, Lippincott-Schwartz utilized advanced imaging techniques to reveal a more accurate picture of how the peripheral endoplasmic reticulum is structured. Their findings may yield new insights for genetic diseases affecting proteins that help shape the endoplasmic reticulum. [6] Additionally, Lippincott-Schwartz's laboratory demonstrated that Golgi enzymes constitutively recycle back to the endoplasmic reticulum and that such recycling plays a central role in the maintenance, biogenesis, and inheritance of the Golgi apparatus in mammalian cells. [7]
Within Lippincott-Schwartz lab, current projects include several cell biological areas. For example, protein transport and cytoskeleton interaction, organelle assembly and disassembly, and cell polarity generation. There are also projects analyzing the dynamics of proteins that have been fluorescently labeled. These proteins are labeled using several live cell imaging techniques such as FRAP, FCS, and photoactivation. [8]
Lippincott-Schwartz has dedicated her most recent lab research to photoactivation localization microscopy (PALM), which allows the viewing of molecular distributions of high densities at the nano-scale. [2]
Jennifer Lippincott-Schwartz was born on October 19, 1952, in Manhattan, Kansas. Her father was a professor of physical chemistry at the University of Maryland [9] and a periodic table could be found hanging in her family's household kitchen. Lippincott-Schwartz's exposure to her father's work is what sparked her love of science. The family moved to a farm in Northern Virginia that had several horses and various other animals. This is where Lippincott-Schwartz found her love of biology.
Lippincott-Schwartz attended Swarthmore College, where she majored in psychology and philosophy and graduated with honors from Swarthmore College in 1974. [2] She taught science at a girl's high school in Kenya for two years before returning to the USA and entering a Master's program in Biology at Stanford University where she worked on DNA repair in the laboratory of Philip Hanawalt. [2] She then entered a Biochemistry Ph.D. program at Johns Hopkins University, where she worked in Douglas Fambrough's lab in the Carnegie Institution of Embryology [2] and studied the dynamics of lysosomal membrane proteins. [10] [11]
After graduating from Johns Hopkins in 1986, Lippincott-Schwartz joined Richard D. Klausner's lab at the National Institutes of Health. Using the drug brefeldin A to perturb membrane trafficking, she showed that membranes cycle between the endoplasmic reticulum and the Golgi, [12] [13] leading to a recognition that cellular organelles are dynamic, self-organized structures that constantly regenerate themselves through intracellular vesicle traffic. [3] [14]
Lippincott-Schwartz became a staff fellow at the National Institute of Child Health and Human Development at NIH in 1990. During this time, Lippincott-Schwartz began developing techniques to use green fluorescent protein (GFP) to visualize cellular trafficking pathways in living cells. [2] [15] She refined the technique of fluorescence recovery after photobleaching (FRAP) to use in studying the dynamics of membrane proteins. In this method, GFP-tagged membrane proteins are subjected to photobleaching in a small area of the cell, and then the cell is imaged to discover how long it takes for non-bleached proteins to replace the bleached ones, i.e. how long it takes for the fluorescence to recover. Before this work, it was thought that the membrane proteins in organelles such as the ER, Golgi, and plasma membrane were fixed in place. However, the FRAP technique proved that molecules within cells move quite rapidly and are able to diffuse freely. [16] Lippincott-Schwartz subsequently introduced photoactivatable GFP that increases its fluorescence after irradiation. [4] This allowed Lippincott-Schwartz and her post-doc George Patterson to track the transport of cargo molecules through the Golgi with great precision, [17] leading to the realization that cargo transport is not an ordered sequential process; instead, the apparently separate membranous stacks of the Golgi are a single continuous structure, and proteins rapidly equilibrate through the layers. [18]
Lippincott-Schwartz's work on photoactivatable GFP led to a collaboration with Eric Betzig of Howard Hughes Medical Institute's Janelia Farm Research Campus in which the ability to turn GFP fluorescence on and off was used to develop one of the first "superresolution imaging" technologies, photoactivation localization microscopy (PALM). [19] The development of "super-resolved fluorescence microscopy" was recognized in 2014 by the award of the Nobel Prize in Chemistry to Eric Betzig along with William E. Moerner of Stanford University, and Stefan W. Hell of Max Planck Institute for Biophysical Chemistry. [20] [21]
Lippincott-Schwartz has used PALM to assess the stoichiometry and composition of membrane receptors [22] and has collaborated with Vladislav Verkhusha of Albert Einstein College of Medicine in New York to develop two-color PALM. [23] She used a combination of five super-resolution techniques to show that the endoplasmic reticulum is composed of a dense tubular matrix, instead of the sheets seen at lower resolution. [24]
In 2016, Lippincott-Schwartz moved from NIH to the Janelia Research Campus of the Howard Hughes Medical Institute to initiate the Neuronal Cell Biology Program at Janelia. [1]
Cell biology is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. Cell biology is the study of the structural and functional units of cells. Cell biology encompasses both prokaryotic and eukaryotic cells and has many subtopics which may include the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition. The study of cells is performed using several microscopy techniques, cell culture, and cell fractionation. These have allowed for and are currently being used for discoveries and research pertaining to how cells function, ultimately giving insight into understanding larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences while also being essential for research in biomedical fields such as cancer, and other diseases. Research in cell biology is interconnected to other fields such as genetics, molecular genetics, molecular biology, medical microbiology, immunology, and cytochemistry.
The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER). The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened, membrane-enclosed sacs known as cisternae, and tubular structures in the SER. The membranes of the ER are continuous with the outer nuclear membrane. The endoplasmic reticulum is not found in red blood cells, or spermatozoa.
The endomembrane system is composed of the different membranes (endomembranes) that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles. In eukaryotes the organelles of the endomembrane system include: the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, endosomes, and plasma (cell) membrane among others. The system is defined more accurately as the set of membranes that forms a single functional and developmental unit, either being connected directly, or exchanging material through vesicle transport. Importantly, the endomembrane system does not include the membranes of plastids or mitochondria, but might have evolved partially from the actions of the latter.
The Golgi apparatus, also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination. It resides at the intersection of the secretory, lysosomal, and endocytic pathways. It is of particular importance in processing proteins for secretion, containing a set of glycosylation enzymes that attach various sugar monomers to proteins as the proteins move through the apparatus.
COPI is a coatomer, a protein complex that coats vesicles transporting proteins from the cis end of the Golgi complex back to the rough endoplasmic reticulum (ER), where they were originally synthesized, and between Golgi compartments. This type of transport is retrograde transport, in contrast to the anterograde transport associated with the COPII protein. The name "COPI" refers to the specific coat protein complex that initiates the budding process on the cis-Golgi membrane. The coat consists of large protein subcomplexes that are made of seven different protein subunits, namely α, β, β', γ, δ, ε and ζ.
Brefeldin A is a lactone antiviral produced by the fungus Penicillium brefeldianum. Brefeldin A inhibits protein transport from the endoplasmic reticulum to the golgi complex indirectly by preventing association of COP-I coat to the Golgi membrane. Brefeldin A was initially isolated with hopes to become an antiviral drug but is now primarily used in research to study protein transport.
The coatomer is a protein complex that coats membrane-bound transport vesicles. Two types of coatomers are known:
Fluorescence Loss in Photobleaching (FLIP) is a fluorescence microscopy technique used to examine movement of molecules inside cells and membranes. A cell membrane is typically labeled with a fluorescent dye to allow for observation. A specific area of this labeled section is then bleached several times using the beam of a confocal laser scanning microscope. After each imaging scan, bleaching occurs again. This occurs several times, to ensure that all accessible fluorophores are bleached since unbleached fluorophores are exchanged for bleached fluorophores, causing movement through the cell membrane. The amount of fluorescence from that region is then measured over a period of time to determine the results of the photobleaching on the cell as a whole.
The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum (ER) stress. It has been found to be conserved between mammalian species, as well as yeast and worm organisms.
Valosin-containing protein (VCP) or transitional endoplasmic reticulum ATPase also known as p97 in mammals and CDC48 in S. cerevisiae, is an enzyme that in humans is encoded by the VCP gene. The TER ATPase is an ATPase enzyme present in all eukaryotes and archaebacteria. Its main function is to segregate protein molecules from large cellular structures such as protein assemblies, organelle membranes and chromatin, and thus facilitate the degradation of released polypeptides by the multi-subunit protease proteasome.
KDEL (Lys-Asp-Glu-Leu) endoplasmic reticulum protein retention receptor 1, also known as KDELR1, is a protein which in humans is encoded by the KDELR1 gene.
BET1 homolog is a protein that in humans is encoded by the BET1 gene.
ER lumen protein retaining receptor 2 is a protein that in humans is encoded by the KDELR2 gene.
KDEL is a target peptide sequence in mammals and plants located on the C-terminal end of the amino acid structure of a protein. The KDEL sequence prevents a protein from being secreted from the endoplasmic reticulum (ER) and facilitates its return if it is accidentally exported.
EosFP is a photoactivatable green to red fluorescent protein. Its green fluorescence (516 nm) switches to red (581 nm) upon UV irradiation of ~390 nm due to a photo-induced modification resulting from a break in the peptide backbone near the chromophore. Eos was first discovered as a tetrameric protein in the stony coral Lobophyllia hemprichii. Like other fluorescent proteins, Eos allows for applications such as the tracking of fusion proteins, multicolour labelling and tracking of cell movement. Several variants of Eos have been engineered for use in specific study systems including mEos2, mEos4 and CaMPARI.
A target peptide is a short peptide chain that directs the transport of a protein to a specific region in the cell, including the nucleus, mitochondria, endoplasmic reticulum (ER), chloroplast, apoplast, peroxisome and plasma membrane. Some target peptides are cleaved from the protein by signal peptidases after the proteins are transported.
Ronald David Vale ForMemRS is an American biochemist and cell biologist. He is a professor at the Department of Cellular and Molecular Pharmacology, University of California, San Francisco. His research is focused on motor proteins, particularly kinesin and dynein. He was awarded the Canada Gairdner International Award for Biomedical Research in 2019, the Shaw Prize in Life Science and Medicine in 2017 together with Ian Gibbons, and the Albert Lasker Award for Basic Medical Research in 2012 alongside Michael Sheetz and James Spudich. He is a fellow of the American Academy of Arts and Sciences and a member of the National Academy of Sciences. He was the president of the American Society for Cell Biology in 2012. He has also been an investigator at the Howard Hughes Medical Institute since 1995. In 2019, Vale was named executive director of the Janelia Research Campus and a vice president of HHMI; his appointment began in early 2020.
David Domingo Sabatini is an Argentine-American cell biologist and the Frederick L. Ehrman Professor Emeritus of Cell Biology in the Department of Cell Biology at New York University School of Medicine, which he chaired from 1972 to 2011. Sabatini's major research interests have been on the mechanisms responsible for the structural complexity of the eukaryotic cell. Throughout his career, Sabatini has been recognized for his efforts in promoting science in Latin America.
Suliana Manley is an American biophysicist. Her research focuses on the development of high-resolution optical instruments, and their application in studying the organization and dynamics of proteins. She is a professor at École Polytechnique Fédérale de Lausanne and heads the Laboratory of Experimental Biophysics.
Harald Frederick Hess is an American physicist and Senior Group Leader at Howard Hughes Medical Institute's Janelia Research Campus, known for his work in scanning probe microscopy, light microscopy and electron microscopy.