Membrane proteins are responsible for conducting essential biological functions that are necessary for the survival of living organisms. In spite of their physiological importance, limited structural information is currently available as a result of challenges in applying biophysical techniques for studying these protein systems. Electron paramagnetic resonance (EPR) spectroscopy is a very powerful technique to study the structural and dynamic properties of membrane proteins. However, the application of EPR spectroscopy to membrane proteins in a native membrane-bound state is extremely challenging due to the complexity observed in inhomogeneity sample preparation and the dynamic motion of the spin label. Detergent micelles are very popular membrane mimetics for membrane proteins due to their smaller size and homogeneity, providing high-resolution structure analysis by solution NMR spectroscopy. However, it is important to test

Objective Glucose concentrations used in current cell culture methods are a significant departure from physiological glucose levels. The study focuses on comparing the effects of glucose concentrations on primary human progenitors (connective tissue progenitors [CTPs]) used for cartilage repair. Design Cartilage- (Outerbridge grade 1, 2, 3; superficial and deep zone cartilage), infrapatellar fatpad-, synovium-, and periosteum-derived cells were obtained from 63 patients undergoing total knee arthroplasty and cultured simultaneously in fresh chondrogenic media containing 25 mM glucose (HGL) or 5 mM glucose (NGL) for pairwise comparison. Automated ASTM-based quantitative image analysis was used to determine colony-forming efficiency (CFE), effective proliferation rates (EPR), and sulfated-proteoglycan (GAG-ECM) staining of the CTPs across tissue sources. Results HGL resulted in increased cell cultures with CFE = 0 compared with NGL in all tissue sources ( P = 0.049). The CFE in NGL was higher than HGL for superficial cartilage ( P < 0.001), and contrary for synovium-derived CTPs ( P = 0.046) when CFE > 0. EPR of the CTPs did not differ between the media in the 6-day assay time period ( P = 0.082). The GAG-ECM area of the CTPs and their progeny was increased in presence of HGL ( P = 0.027). Conclusion Glucose concentration is critical to progenitor’s physiology and should be taken into account in the setting of protocols for clinical or in vitro cell expansion strategies.

The oncoprotein E5 from papilloma virus can activate the platelet derived growth factor b receptor (PDGFbR) in the membrane through an interaction of the transmembrane helices. This triggers the signal cascade in a ligandindependent manner, leading to pathogenic growth and cancer. However, is not yet known how the E5 and the PDGFbR interact with each other. Therefore, we aim at getting insight into the structure of this oligomeric complex and condition for its self-assembly using solid-state NMR measurements of intermolecular distances. Unlike most other structural biological methods, solidstate NMR allows to study oligomeric complexes in a native-like membrane environment, which is required to correctly represent the oligomeric structures.Here, REDOR is one of the most commonly used NMR technologies and is employed for distance measurements between two different spins. Selective 13 C-,

Image 1. Chronic endothelialized scar tissue extracted surgically (during a pulmonary endarterectomy) from a patient with chronic thromboembolic pulmonary hypertension.