On the interactions of lipids and proteins in the red blood cell membrane

The effects of temperature and of the action of a purified phospholipase C enzyme preparation on human red blood cell membranes has been investigated by chemical analyses, circular dichroism, and proton magnetic resonance measurements. The results indicate that a substantial fraction of the phospholipids and the proteins of the membranes can change structure independently of one another, suggesting a mosaic pattern for the organization of the lipids and proteins in membranes

Rethinking performance benchmarks in kidney transplantation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145501/1/ajt14947_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145501/2/ajt14947.pd

Force transduction by Triton cytoskeletons

Force-initiated signal transduction can occur either via membrane-based ionic mechanisms or through changes in cytoskeletal–matrix linkages. We report here the stretch-dependent binding of cytoplasmic proteins to Triton X-100 cytoskeletons of L-929 cells grown on collagen-coated silicone. Triton X-100–insoluble cytoskeletons were stretched by 10% and incubated with biotinylated cytoplasmic proteins. Analysis with two-dimensional gel electrophoresis showed stretch-dependent binding of more than 10 cytoplasmic protein spots. Bound cytoplasmic proteins were purified by a photocleavable biotin tag and stretch-dependent binding of paxillin, focal adhesion kinase, and p130Cas was found, whereas the binding of vinculin was unchanged and actin binding decreased with stretch. Paxillin binding upon stretch was morphologically and biochemically similar in vitro and in vivo, that is, enhanced in the periphery and inhibited by the tyrosine phosphatase inhibitor, phenylarsine oxide. Thus, we suggest that transduction of matrix forces occurs through force-dependent conformation changes in the integrated cytoskeleton

Direct evidence for coherent low velocity axonal transport of mitochondria

Axonal growth depends on axonal transport. We report the first global analysis of mitochondrial transport during axonal growth and pauses. In the proximal axon, we found that docked mitochondria attached to the cytoskeletal framework that were stationary relative to the substrate and fast axonal transport fully accounted for mitochondrial transport. In the distal axon, we found both fast mitochondrial transport and a coherent slow transport of the mitochondria docked to the axonal framework (low velocity transport [LVT]). LVT was distinct from previously described transport processes; it was coupled with stretching of the axonal framework and, surprisingly, was independent of growth cone advance. Fast mitochondrial transport decreased and LVT increased in a proximodistal gradient along the axon, but together they generated a constant mitochondrial flux. These findings suggest that the viscoelastic stretching/creep of axons caused by tension exerted by the growth cone, with or without advance, is seen as LVT that is followed by compensatory intercalated addition of new mitochondria by fast axonal transport