Degradation of Ubiquitin-conjugated proteins is performed by the intracellular protease known as the 26S proteasome. The ubiquitin-proteasome proteind degradation pathway is also termed endoplasmic reticulum associated degradation (ERAD). After ERAD substrates are selected in the ER, they are exported, or "retro-translocated" to the cytoplasm and destroyed by the cytoplasmic proteasome, a large multi-catalytic protease with a central barrel where unfolded Ub-tagged proteins are hydrolyzed. Reported in a paper in EMBO J., are findings that the proteasome itself can provide the driving force for translocation. The cap, or 19S particle can hydrolyze ATP and extract a polypeptide from the ER.[s]
Џ beautiful Flash 8 animation - Inner Life of the Cell, which shows vesicles budding from the Golgi complex ; and, Interpretation: Inner Life of the Cell Џ
 26s proteasome  3D structure of targetted peptide  barrel and subunits of proteasome  proteasome assembly  proteasome engine  substrate swapping  Ub-proteasome pathway  yeast 20s proteasome ribbon, yeast 20s proteasome down the barrel, surface with bound aldehyde indicators Џ animation - proteasome Џ animation - importing, unfolding, hydrolyzing Џ
Aberrant Ub-mediated protein degradation has been implicated in a number of pathological conditions, particularly neurodegenerative disorders that involve protein aggregation and inclusion body formation, where protein misfolding may play a role –Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and ALS.
: diag. ubiquitin-mediated degradation :
• A • adhesion • C • cell membranes • cellular adhesion molecules • cellular signal transduction • centrioles • chemotaxis • chloroplast • cilia & flagella • communication • concentration gradients • cytokine receptors • cytoplasm • cytoskeleton • E • energy transducers • endoplasmic reticulum • endosomes • exosome • F • flagella & cilia • G • Golgi apparatus • GPCRs • H • hormones • I • ion channels • L • lysosome • M • meiosis • microtubules • mitosis • mitochondrion • N • Nitric Oxide • neurotransmission • neuronal interconnections • nuclear membrane • nuclear pore • P • pinocytosis • proteasome • pumps • R • receptor proteins • receptor-mediated endocytosis • S • second messengers • signaling gradients • signal transduction • spindle • structure • T • transport • two-component systems • V • vacuole • vesicle •
animation - golgi apparatus and budding golgi body : animation - golgi at work : animation - lysosomes "suicide sacks" : tour lysosome : Virtual Cell Textbook - Cell Biology :