iBiology Podcasts

What is the involvement of microRNAs in the inflammatory response? In this seminar, Dr. David Baltimore shows that the expression of three microRNAs (miR-132, miR-146, and miR-155) increase upon activation of the inflammatory pathway. Baltimore characterizes these microRNAs and shows how they are involved in the precise tuning of the inflammatory response. Continue Reading

Ashcroft expands on what is known about the KATP channel and its role in insulin secretion.  It is an octomeric complex composed of 4 Kir6.2 subunits and 4 SUR1 subunits. ATP binds to both proteins, and changes in metabolically generated ATP couple metabolism to KATP channel activity. Functional studies showed that the KATP channel mutations… Continue Reading

Dr. Norma Andrews overviews the mechanisms of cellular plasma membrane repair. As she describes, a lesion is followed by a Ca2+-dependent movement of vesicles to the plasma membrane. By studying how the Trypanosoma cruzi parasite enters the cell, Andrews’ laboratory discovered that an increase of intracellular calcium was triggering lysosomal fusion to the plasma membrane…. Continue Reading

Andrews further explains how Ca2+-dependent exocytosis of lysosomes aids membrane repair. Her laboratory showed that after lysosomal exocytosis, an injury to the plasma membrane would also trigger a Ca2+-dependent endocytosis that is required for the repair mechanism. Andrews laboratory showed that lysosomes release the enzyme acid sphingomyelinase (ASM) which induce the endocytosis required for plasma… Continue Reading

Injecting adult stem cells into the bloodstream could help regenerate tissue damaged by heart attacks. For this to happen, circulating stem cells need to exit blood vessels and reach the damaged tissue. While scientists knew that circulating stem cells are able to exit the bloodstream, how they did it was a mystery. In this lecture,… Continue Reading

Many of us are used to seeing cartoons of cells with organelles shown as static, isolated structures. Continue Reading

Voeltz explains how her lab used a BioID strategy to identify some of the proteins found at membrane contact sites between the ER and endosomes; a difficult task given the transient nature of contact sites. Continue Reading

Eukaryotic cells have many different membrane-bound organelles with distinct functions and characteristic shapes. How does this happen? Dr. Tom Rapoport explains the important role of protein sorting in determining organelle shape and function. Continue Reading

The ER is a vast network that includes different domains with different functions. The rough ER is made of ribosome covered membrane sheets and is involved in protein translation. Continue Reading

Dan Littman discusses the opposing roles of Th17 cells. They protect mucosal surfaces from infection with bacteria and fungi, but they can also cause autoimmune inflammation. Continue Reading

Littman explains that different commensal microbes in our gut elicit different T cell responses – either pathogenic or non-pathogenic. Continue Reading

In mammals, sex is determined by a pair of unequal sex chromosomes. Genetically male mammals have an X and a Y chromosome while genetically female mammals have two X chromosomes. The X chromosome is many times larger than the Y chromosome. To compensate for this genetic inequality, female mammals undergo X chromosome inactivation in which… Continue Reading

Lee elaborates on the early steps of X inactivation. Very early in development, cells “count” the number of X chromosomes and decide if one needs to be inactivated, and if so which one. There is a region of the X chromosome called the X inactivation center which is enriched in long non-coding RNAs (lncRNAs). Lee… Continue Reading

Lee describes how X inactivation is nucleated and spreads across the X chromosome. The Xist lncRNA is known to be necessary and sufficient for X inactivation. Lee describes experiments that identified the factors that tether Xist to the X chromosome and showed how Xist spreads to cover the entire X chromosome. She then goes on… Continue Reading

Dr. Susanne Heck begins her talk by explaining why we might choose to use mass cytometry rather than other types of flow cytometry.  Traditional flow cytometry is typically limited to the detection of about a dozen parameters in one sample due to overlap between the emission spectra of fluorochromes used to label antibodies.  Mass cytometry,… Continue Reading

The expansion of lungs for oxygen uptake is facilitated by lung surfactant. The groundbreaking discovery of this substance was made by Dr. John Clements. In this Discovery Talk, Clements details his scientific journey, touching on his early research, the resistance he encountered in the field, and the discovery of lung surfactant, which has saved millions… Continue Reading

There are many processes and signals in cells that must be turned on and off, sometimes very quickly.  How is this done? One important way is via post-translational modification of proteins such as phosphorylation or dephosphorylation. In her first talk, Dr. Anne Bertolotti introduces us to protein phosphatases, the enzymes that remove phosphate from proteins… Continue Reading

Bertolotti’s lab has had a long time interest in understanding protein folding and the role of misfolded proteins in neurodegenerative disease. In her second talk, Bertolotti explains how her lab found that selectively inhibiting the dephosphorylation of eIF2⍺, a translation initiation factor, led to a reduction in protein synthesis. Decreasing protein synthesis allowed cells to… Continue Reading

Bertolotti describes a platform developed by her lab that has allowed them to rationally identify selective protein phosphatase inhibitors. Using this platform her lab identified a novel small molecule phosphatase inhibitor that blocks the accumulation of misfolded proteins in the cytosol or nucleus and showed the therapeutic effects of the molecule in a model of… Continue Reading

Brittany Anderton provides an overview of the major cells of the human immune system. Continue Reading

Brangwynne tells us about recent work in which his lab has used light to control phase separation behavior in cells. By linking IDRs from proteins that are known to phase separate to protein domains that weakly oligomerize in response to light, his lab has generated tools that are allowing them to investigate the role of… Continue Reading

Brangwynne focuses on the formation of the nucleolus; one of several membrane-less bodies found in the nucleus. Brangwynne’s lab was able to show that assembly of the nucleolus also can be described by the physics of phase separation. Continue Reading

How do the tiny, crowded, constantly moving molecules inside of cells come together to form functional structures such as organelles? Dr. Cliff Brangwynne explains that many of the organelles we are familiar with, such as the nucleus and the Golgi apparatus, are membrane bound. However, some organelles, such as P granules and nuclear bodies, are… Continue Reading

Förster Resonance Energy Transfer (FRET) microscopy is a technique that allows monitoring of interactions between dyes that occur on the nanometer scale. This sensitivity to small changes in distance and orientation make it a popular technique for building biosensors. Here, Philippe Bastiaens describes the physics behind FRET and how FRET can be measured with a… Continue Reading