Article Abstract:
Fusion processes in the ER-nuclear envelope and the Golgi complex are controlled by two proteins, the yeast and mammalian N-ethylmalemide-sensitive factor (NSF) and the yeast valosin-containing protein p97 or its mammalian homolog Cdc48. The amino acid sequence of the Cdc48 is similar to that of NSF. Although the activity of these proteins is similar the mechanism of action is different. Fusion involves the interaction of the SNAP protein receptors with SNAPs or NSF or the fusion of the yeast nuclear envelop during mating which involves the cell division cycle CDC48 gene.
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Article Abstract:
The transport of major histocompatibility complex (MHC) class II molecules are hypothesized to play a role in developmental regulation. This was tested in mouse dendritic cells (DCs) as they are the most potent of all antigen presenting cells. Investigations show that the transport of MHC class II molecules are controlled by DCs through the cleavage of the third polypeptide invariant (Ii) chain. Cathepsin S is the enzyme thought to be responsible for cleaving the Ii chain. This in turn is controlled by the down-regulation of the cysteine protease inhibitor cystatin C.
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Article Abstract:
A functional association with cytoplasmic coat proteins of the ARF and COP-I families affects the activity of endosomes, formed during receptor-mediated endocytosis. GTP-gamma-S activates the association, while brefeldin A inhibits it. A mutation in the epsilon-COP gene disrupts the sorting activity of the endosomes, suppressing the recycling of low density lipoproteins. Antibodies against beta-COP inhibit the formation of endosomes and prevent the entry of vesicular stomatitis virus into the endocytic pathway.
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