My mother, the wave

The checkpoint of death ells that fail to turn on a signaling pathway as instructed go on to commit suicide, according to Olivier Micheau and Jürg Tschopp (University of Lausanne, Switzerland). This checkpoint mechanism may ensure that aberrant signalers do not survive to form tumors or inappropriate cell types. The mechanism explains how death and differentiation are coordinated from a single receptor, the TNF-receptor I (TNFR1). A host of proteins has been implicated in signaling from TNFR1, but these links have relied on overexpression experiments. On looking more carefully, the Swiss team found that a group of proteins formed complex I with TNFR1, and then later peeled away from TNFR1 and the plasma membrane to form the largely cytoplasmic complex II. Only in complex II were death domains available for the binding of other proteins such as FADD, with their recruitment leading to apoptosis. But if complex I performed its signaling job correctly, the downstream NF-␬ B pathway was turned on to produce FLIP L. This protein shut down the proapoptotic activity of complex II, and thus cells survived. If the cell has a defect in the NF-␬ B pathway, says Tschopp, " this cell is probably a dangerous cell, and it needs to be eliminated. " But intact signaling prevents this death, after a delay that allows sufficient time to make sure that the NF-␬ B pathway is behaving correctly. ᭿ A cytoplasmic complex induces death if the NF-␬B pathway is not intact. cean waves continue to wash through our every cell, They have found that oscillatory metabo-lism—a more efficient method of creating chemical energy even with constant nutrient inputs—develops faster and more efficiently in response to oscillatory inputs such as the wash of nutrients from seashore waves. Thus such metabolism may have arisen at the seashore and then spread over the rest of the Earth. Oscillatory metabolism has been seen in reactions such as glycolysis and proton import into mitochondria. The Stanford group earlier showed that oscillatory metabolism can be more efficient than linear metabolism as the oscillations force large amounts of reactants through a reaction when the reactant to product ratio is at its maximum. (This is comparable to the rush of electrical current at the peak voltage of an alternating current [AC] network.) But how did the oscillations first arise? After staring at waves in a cove in La Jolla, CA, and seeing a paper stating …