Speaker
Zev Bryant

Description Cytoskeletal motors drive the transport of organelles and molecular cargoes within cells and have potential applications in molecular detection and diagnostic devices. Engineering molecular motors with controllable properties will allow selective perturbation of mechanical processes in living cells and provide optimized device components for tasks such as molecular sorting and directed assembly. Biological motors have previously been modified by introducing activation/deactivation switches that respond to metal ions and other signals. Here, we show that myosin motors can be engineered to reversibly change their direction of motion in response to a calcium signal. Building on previous protein engineering studies and guided by a structural model for the redirected power stroke of myosin VI, we have constructed bidirectional myosins through the rigid recombination of structural modules. The performance of the motors was confirmed using gliding filament assays and single fluorophore tracking. Our strategy, in which external signals trigger changes in the geometry and mechanics of myosin lever arms, should make it possible to achieve spatio temporal control over a range of motor properties including processivity, stride size and branchpoint turning.

Description

The Nanoscience and Nanotechnology Institute IN2UB and the Small Biosystems Lab from the University of Barcelona are pleased to invite you to a series of three lectures on molecular biophysics. Prof. Zev Bryant from Stanford University (Stanford, California) will deliver the lectures, reviewing recent developments to which he and his colleagues have recently contributed. The course is aimed to foster exchanges between students and faculties of both institutions. The laboratory of Prof. Zev Bryant seeks to understand the physical mechanisms by which molecular motors convert chemical energy into mechanical work. They use single molecule tracking and manipulation techniques to follow in real time the activity of individual motors and observe the substeps of the motor mechanochemical cycle. They use protein engineering tools to explore the relationship between molecular structure and mechanical function. In this short lecture series Prof. Bryant will give some perspective on mechanical adaptations of unconventional myosins and torque generation by DNA-associated ATPases.

Organizers
IN2UB and Small Biosystems Lab from University of Barcelona

Speaker
Sunil Kumar

Description In this talk I will discuss some morphological changes in membranes as the result of (1) coupling to a spectrin like elastic network and (2) due to the flux of lipids and proteins in and out . Balloon-shaped membrane protrusions, called blebs, can form during physiological processes such as cytokinesis, cell motility and apoptosis. Computer simulation of a particle-based model for self assembled lipid bilayers coupled to an elastic meshwork, is used to investigate the phase behavior and kinetics of blebbing. We find that blebs form when the mismatch parameter, defined as the ratio between the area of the lipid bilayer and the rest area of the cytoskeleton, exceeds a value determined by the cytoskeleton rest area. We also found that blebbing occurs when membranes are subjected to localized ablation of the cytoskeleton or a uniform compression. In a biological cell, the plasma membrane and its organelles are subjected to a constant flux of lipids and proteins arising through energy consuming ({\em active}) inter and intra cellular material transport. Here we investigate, through Monte Carlo simulations, the role some that these processes play in determining the morphology of closed membrane surfaces. A spontaneous curvature based two phase model, in the semi grand ensemble, has been used to model effects of molecular binding/conformational change. The presence of activity inhibits phase segregation and drives the membrane into many biologically relevant, steady state shapes.

Speaker
Mark Sinclair

Description This talk will cover a selection of topics in financial mathematics, with applicability to the areas of banking and insurance. The focus will be on practical applications and how to apply mathematics to meet the real needs of banks and insurers, rather than a detailed discussion of the underlying theory. In particular, the following topics will be discussed: · Solvency II & Basel III: impact of regulation on client requirements in the banking and insurance sectors. · Insurance: o Modelling an insurer: reserving risk, underwriting risk and asset risk. o Economic Scenario Generation (ESG): calibrating and projecting economic models. o Capital: determination & allocation. o Reinsurance optimisation. o Portfolio optimisation. · Banking: o Valuation: valuing a portfolio of assets using real-world and risk-neutral measures. o Determining PFE (Potential Future Exposure). o Determining CVA (Credit Value Adjustment). o Collateral optimisation. Many of the topics discussed have equal applicability to both banking and insurance. For instance, the calibration and projection of interest-rate models, such as Hull-White or the Libor Market Model, is very much used in both areas.

Speaker
Ruben Requejo