Search

Results show that during mitotic cell division Golgi membranes disperse and reform across endoplasm reticulum, maximally using constitutive recycling pathways. Data further indicate that endoplasm reticulum plays an essential role in the Golgi coplex's genesis and inheritance.

Endoplasmic reticulum (ER)-specific chaperones and folding enzymes facilitate folding and unfolding reactions of the newly synthesized proteins in the ER and are known to serve a quality control function, allowing only correctly assembled and folded proteins to exit the compartment. A new study investigates the extent to which proteins leaving the ER return to its folding environment from the Golgi complex. It is concluded that recycling is not induced by misfolded proteins and is not signal-mediated, but could be an inherent property of proteins within the Golgi membranes.

Proteins from the endoplasmic reticulum (ER) are channelled through the Golgi complex before being transported to their final destinations. It is now possible to follow the entire life history of a single transport intermediates in living cells, through new florescent tagging techniques. ER-to-Golgi transport has been visualized through the use of tso45 VSVG, a viral glycoprotein, tagged with green fluorescent protein.

The mechanism by which Golgi membrane proteins are retained within the Golgi complex in the midst of a continuous flow of protein and lipid is not yet understood. The diffusional mobilities of mammalian Golgi membrane proteins fused with green fluorescent protein from Aequorea victoria were measured in living HeLa cells with the fluorescence photobleaching recovery technique. The diffusion coefficients ranged from 3 x [10.sup.-9] square centimeters per second to 5 x [10.sup.-9] square centimeters per second, with greater than 90 percent of the chimeric proteins mobile. Extensive lateral diffusion of the chimeric proteins occurred between Golgi stacks. Thus, the chimeras diffuse rapidly and freely in Golgi membranes, which suggests that Golgi targeting and retention of these molecules does not depend on protein immobilization., The Golgi complex contains a large number of resident components that play important roles in the processing and sorting of secretory and membrane proteins, but how these components are maintained [...]

Vaccinia virus gene, a viral prolifin in the Escherichia coli, exhibits a binding property with the phosphatidylinositol 4,5-biphosphate and phosphatidylinositol 4-monophosphate in large unilamellar vesicles and mucelles. The prolifin does not bind to phosphatidylcholine and phosphatidylserine. The characterization of these interactions reveals that the process of binding of the prolifin is very slow, the rate constants ranging from 1 to 4 X 10 to the power 4 per mole per second.

Steady-state kinetic modeling of [1-(super 14)C]20:4n-6 metabolism in vivo coupled with studies using enzyme assays and mRNA expression of key fatty acid metabolic enzymes is used to address the potential role for [alpha]-synuclein in brain 20:4n-6 uptake metabolism. The addition of wild-type (wt) human or mouse [alpha]-synuclein completely restored acyl-CoA synthetase activity in these microsomes, while the A30P, E46K, and A53T mutant forms of [alpha]-synuclein failed to restore activity.

Alpha-Synuclein contains protein in the central nervous system that is connected with a number of neurodegenerative disorders. A wild type, or alpha-synuclein mice with palmitic acid (16:0) and assessed fatty acid uptake and turnover kinetics in brain phospholipids were infused to define a role of alpha-synuclein in brain fatty acid uptake and metabolism.