The exosome complex is a multi-protein complex, capable of degrading various types of RNAs. Exosome complexes can be found in both eukaryotic cells and archaea, while in bacteria a simpler complex called the degradosome carries out similar functions. The core of the complex has a six-membered ring structure, to which other proteins are attached. In eukaryotic cells, it is present in the cytoplasm, nucleus and especially the nucleolus, although different proteins interact with the complex in these compartments, in order to regulate the RNA degradation activity of the complex to substrates specific for these cell compartments. Substrates of the exosome include messenger RNA, ribosomal RNA, and many species of small RNAs. The exosome has an exoribonucleolytic function, meaning it degrades RNA starting at one side (the so-called 3' end in this case), rather than cleaving the RNA at specific sites. Although no causative relation between the complex and any disease is known, several proteins in the complex are the target of autoantibodies in patients with specific autoimmune diseases (especially the PM/Scl overlap syndrome) and some antimetabolitic chemotherapies for cancer function by blocking the activity of the complex.

Read the rest of this article: http://en.wikipedia.org/wiki/Exosome_complex

_______________________________ Today's selected anniversaries:

553:

The Second Council of Constantinople, believed to have been the fifth Christian Ecumenical Council, began to discuss the topics of Nestorianism and Origenism, among others. http://en.wikipedia.org/wiki/Second_Council_of_Constantinople

1789:

The Estates-General convened in Versailles to discuss a financial crisis in France, triggering a series of events that led to the French Revolution. http://en.wikipedia.org/wiki/Estates-General_of_1789

1949:

Ten European countries signed the Treaty of London, creating the Council of Europe, today one of the oldest international organisations working for European integration. http://en.wikipedia.org/wiki/Council_of_Europe

1950:

Prince Bhumibol Adulyadej was crowned in Bangkok as King Rama IX of Thailand, currently the world's longest-serving head of state. http://en.wikipedia.org/wiki/Bhumibol_Adulyadej

1994:

Armenia and Azerbaijan signed the Bishkek Protocol, a provisional ceasefire treaty to end hostilities in the Nagorno-Karabakh War, with both sides agreeing, among others, to grant a wide-ranging autonomy to the Nagorno-Karabakh region. http://en.wikipedia.org/wiki/Nagorno-Karabakh_War

_____________________________ Wiktionary's word of the day:

stygian (adj): 1. Dark and gloomy.

2. Infernal or hellish. 3. Of, or relating to the river Styx http://en.wiktionary.org/wiki/stygian

___________________________ Wikiquote quote of the day:

If I have ventured wrongly, very well, life then helps me with its penalty. But if I haven't ventured at all, who helps me then? --Søren Kierkegaard http://en.wikiquote.org/wiki/S%C3%B8ren_Kierkegaard