In situ quantitative imaging of cellular lipids using molecular sensors.

Membrane lipids are dynamic molecules that play important roles in cell signalling and regulation, but an in situ imaging method for quantitatively tracking lipids in living cells is lacking at present. Here, we report a new chemical method of quantitative lipid imaging using sensors engineered by labelling proteins with an environmentally sensitive fluorophore. A prototype sensor for phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2))--a key signalling lipid in diverse cellular processes--was generated by covalently attaching a single 2-dimethylamino-6-acyl-naphthalene group to the N-terminal α-helix of the engineered epsin1 ENTH domain, a protein that selectively binds PtdIns(4,5)P(2).

Molecular basis of the potent membrane-remodeling activity of the epsin 1 N-terminal homology domain.

The mechanisms by which cytosolic proteins reversibly bind the membrane and induce the curvature for membrane trafficking and remodeling remain elusive. The epsin N-terminal homology (ENTH) domain has potent vesicle tubulation activity despite a lack of intrinsic molecular curvature. EPR revealed that the N-terminal alpha-helix penetrates the phosphatidylinositol 4,5-bisphosphate-containing membrane at a unique oblique angle and concomitantly interacts closely with helices from neighboring molecules in an antiparallel orientation.

An observational study of safety belt use among taxi drivers in Boston.

Study Objective: Although safety belt legislation exists for drivers in Massachusetts, there is an exemption for taxicab drivers. According to the most recent data from the Governor's Highway Safety Bureau, the observed safety belt use rate of drivers in Massachusetts is 64%. However, the safety belt use among taxicab drivers in Boston is unknown.