Waxing philosophical on plant GPATs
Plants possess extracellular waxy polymer layers which protect them from dehydration and pathogens. This waxy layer is called suberin in the root and cutin on aerial tissues. Mutant analyses and over-expression studies indicate that glycerol-3-phosphate acyltransferases (GPATs) 4,5,6, and 8 synthesize some of the building blocks these waxy extracellular polymers.
Reviewed by: Matthew Keogh,UNC-Chapel Hill
Posted on: 21 July 2010
Hyperactive Cholesterol Breaks Free to Signal Enough is Enough
Sometimes cholesterol is happy just to hang with its phospholipid partners and mellow them out. But when levels of membrane cholesterol start to rise, lipid crowding creates a cadre of cholesterol with activist tendencies.
Reviewed by: Binks Wattenberg, University of Louisville
Posted on: 15 July 2010
A Case of the FITs: Lipid Droplet Packaging Proteins?
David Silver and his colleagues at Albert Einstein College of Medicine reported in 2008 a screen for novel genes activated by PPARalpha (1). This transcription factor promotes adipogenesis in mammals. They identified two related genes: FIT (fat-inducing transcript)-1 and FIT2. Expression of FIT genes leads to an increase in lipid droplets and an increase in triacylglycerol.
Reviewed by Joel Goodman, UT-Southwestern Medical Center
Posten on: 08 July 2010
Eat your carrots in the sunshine: Bile acid synthesis is regulated by vitamins A and D
Eat your carrots in the sunshine Bile acid synthesis is regulated by vitamins A and D It has long been known that bile acid synthesis, the end product of cholesterol catabolism in the liver, is regulated through feedback inhibition that....
Reviewed by Nicholas O. Davidson, Washington University School of Medicine
Posted on: 07 July 2010
Mitochondria take central stage in “the ceramide-centric universe of lipid-mediated cell regulation”
Sphingomyelinases are phosphodiesterases that cleave the phosphorylcholine head group of sphingomyelin to generate ceramide. During cell signaling they are the main pathway that generates ceramide, a bioactive lipid that regulates cell growth, differentiation, and apoptosis; hence, the sphingomyelinases have been exhaustedly studied for more than two decades. Only recently, however, have the sphingomyelinases begun to reveal their molecular personalities. One acid sphingomyelinase (aSMase1) and three neutral sphingomyelinases (nSMase 1,2, and 3) are encoded by four different genes (smpd1, 2, 3, and 4, respectively) and are found in different subcellular compartments. ASMase1 is located in the endo-lysosomes, nSMase1 in the ER, nSMase2, in the plasma membrane, and nSMase3 in the ER/Golgi. Now, a recent article by Wu, et al. (1) describes a novel neutral sphingomyelinase, encoded by smpd5, that seems to be preferentially located in the mitochondria!
Posted on: 28 June 2010