How Cells Choose to Create Energy

To supply their energy needs, cells typically choose between utilizing glucose in the cytoplasm (aerobic glycolysis and lactic acid fermentation) or “burning” pyruvate in the mitochondria (mitochondrial carbohydrate oxidation). Although this is arguably the most fundamental metabolic decision that cells make, before 2012 it was not clear how cells import pyruvate into mitochondria to fuel ATP production. Continue reading → How Cells Choose to Create Energy

Structures and Mechanisms of Protein Remodeling Machines

When a cellular protein has done its job or lost its utility, it should be removed, recycled, or remodeled. These tasks are performed by members of the ubiquitous family of AAA ATPases (ATPases associated with diverse cellular activities) that convert the energy of ATP hydrolysis into mechanical forces that can unfold protein aggregates, degrade unwanted proteins, and remodel protein complexes. Continue reading → Structures and Mechanisms of Protein Remodeling Machines

Fast-acting Insulins from Cone Snails

Faster acting human insulins are needed to improve the efficacy of diabetic insulin pumps. Over the past few years, collaborating teams led by Olivera, Safavi-Hemami, Schlegel, Yandell, and Chou have made the remarkable discovery that fish-hunting cone snails use fast-acting insulins to inactivate their prey by inducing hypoglycemia. Continue reading → Fast-acting Insulins from Cone Snails

Sensing and Regulating Cellular Energy Production

Cells must decide when to expand mitochondrial capacity to accommodate increased energy demands. Rutter, Winge, and colleagues have shown that the ancient mitochondrial fatty acid synthesis system has a profound and unexpected regulatory role in driving mitochondrial biogenesis. Continue reading → Sensing and Regulating Cellular Energy Production

Structure and Function of the Polycystic Kidney Disease Channel

The kidney senses and responds to physiological changes, such as pH, ionic strength, pressure, and nutrient levels. Sensing is mediated by a coupled sensor/ion channel complex called the Polycystic Kidney Disease Channel, which is composed of two subunits, the PKD1 (the primary sensor) and PKD2 (the channel). Continue reading → Structure and Function of the Polycystic Kidney Disease Channel

Animation of the HIV Life Cycle

Atomically accurate molecular animations provide a unique opportunity for generating and testing new mechanistic hypotheses and promoting scientific communication and public outreach. Iwasa is a leader in the creation of sophisticated, dynamic 3D visualizations of biological processes. Continue reading → Animation of the HIV Life Cycle

Identifying RNAs from Invading Viruses

Biochemical and structural studies from Bass, Shen, Iwasa, and colleagues revealed how Dicer-2, an RNA processing, and antiviral defense enzyme, distinguishes and differentially processes double-stranded RNA (dsRNA) substrates by sensing the unique chemistry at their termini. Continue reading → Identifying RNAs from Invading Viruses

Viral RNA Modulation of Host Gene Expression

Viruses depend on and modulate their hosts’ cellular environments to maximize replication. Cazalla and colleagues studied the small RNAs from H. saimiri, a herpesvirus that establishes latency in the T cells of New World primates and can cause aggressive leukemias and lymphomas in non-natural hosts. Continue reading → Viral RNA Modulation of Host Gene Expression

Cellular Membrane Remodeling

Cells are continually severing, fusing, and reshaping their membranes. One of the essential cellular membrane remodeling systems is the ESCRT (Endosomal Sorting Complexes Required for Transport) pathway, whose cellular functions include endosomal membrane remodeling, membrane repair, enveloped virus budding, closure of the nuclear envelope, and cytokinetic abscission. Continue reading → Cellular Membrane Remodeling