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ERN1
The serine/threonine-protein kinase/endoribonuclease inositol-requiring enzyme 1 α (IRE1α) is an enzyme that in humans is encoded by the ''ERN1'' gene. Function The protein encoded by this gene is the ER to nucleus signalling 1 protein, a human homologue of the yeast Ire1 gene product. This protein possesses intrinsic kinase activity and an endoribonuclease activity and it is important in altering gene expression as a response to endoplasmic reticulum-based stress signals (mainly the unfolded protein response). Two alternatively spliced transcript variants encoding different isoforms have been found for this gene. Signaling IRE1α possesses two functional enzymatic domains, an endonuclease and a trans-autophosphorylation kinase domain. Upon activation, IRE1α oligomerizes and carries out an unconventional RNA splicing activity, removing an intron from the X-box binding protein 1 (XBP1) mRNA, and allowing it to become translated into a functional transcription factor, XBP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Shock Protein 90kDa Alpha (cytosolic), Member A1
Heat shock protein HSP 90-alpha is a protein that in humans is encoded by the ''HSP90AA1'' gene. Function The gene, HSP90AA1, encodes the human stress-inducible 90-kDa heat shock protein alpha (Hsp90A). Complemented by the constitutively expressed paralog Hsp90B which shares over 85% amino acid sequence identity, Hsp90A expression is initiated when a cell experiences proteotoxic stress. Once expressed Hsp90A dimers operate as molecular chaperones that bind and fold other proteins into their functional 3-dimensional structures. This molecular chaperoning ability of Hsp90A is driven by a cycle of structural rearrangements fueled by ATP hydrolysis. Current research on Hsp90A focuses in its role as a drug target due to its interaction with a large number of tumor promoting proteins and its role in cellular stress adaptation. Gene structure Human HSP90AA1 is encoded on the complement strand of Chromosome 14q32.33 and spans over 59 kbp. Several pseudogenes of HSP90AA1 exist th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unfolded Protein Response
The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum (ER) stress. It has been found to be conserved between all mammalian species, as well as yeast and worm organisms. The UPR is activated in response to an accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum. In this scenario, the UPR has three aims: initially to restore normal function of the cell by halting protein translation, degrading misfolded proteins, and activating the signalling pathways that lead to increasing the production of molecular chaperones involved in protein folding. If these objectives are not achieved within a certain time span or the disruption is prolonged, the UPR aims towards apoptosis. Sustained overactivation of the UPR has been implicated in prion diseases as well as several other neurodegenerative diseases, and inhibiting the UPR could become a treatment for those diseases. Diseases amenable to UPR inhibition inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ERAD
Endoplasmic-reticulum-associated protein degradation (ERAD) designates a Cell (biology), cellular pathway which targets misfolded proteins of the endoplasmic reticulum for ubiquitination and subsequent degradation by a protein-degrading complex, called the proteasome. Mechanism The process of ERAD can be divided into three steps: Recognition of misfolded or mutated proteins in the endoplasmic reticulum The recognition of misfolded or mutated proteins depends on the detection of substructures within proteins such as exposed hydrophobic regions, unpaired cysteine residues and immature glycans. In mammalian cells for example, there exists a mechanism called glycan processing. In this mechanism, the lectin-type Chaperone (protein), chaperones calnexin/calreticulin (CNX/CRT) provide immature glycoproteins the opportunity to reach their native conformation. They can do this by way of reglucosylating these glycoproteins by an enzyme called Uridine diphosphate, UDP-glucose-glycopro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most common type of motor neuron diseases. Early symptoms of ALS include stiff muscles, muscle twitches, and gradual increasing weakness and muscle wasting. ''Limb-onset ALS'' begins with weakness in the arms or legs, while ''bulbar-onset ALS'' begins with difficulty speaking or swallowing. Half of the people with ALS develop at least mild difficulties with thinking and behavior, and about 15% develop frontotemporal dementia. Most people experience pain. The affected muscles are responsible for chewing food, speaking, and walking. Motor neuron loss continues until the ability to eat, speak, move, and finally the ability to breathe is lost. ALS eventually causes paralysis and early death, usually from respiratory failure. Most cases of ALS (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parkinson's Disease
Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms become more common. The most obvious early symptoms are tremor, rigidity, slowness of movement, and difficulty with walking. Cognitive and behavioral problems may also occur with depression, anxiety, and apathy occurring in many people with PD. Parkinson's disease dementia becomes common in the advanced stages of the disease. Those with Parkinson's can also have problems with their sleep and sensory systems. The motor symptoms of the disease result from the death of cells in the substantia nigra, a region of the midbrain, leading to a dopamine deficit. The cause of this cell death is poorly understood, but involves the build-up of misfolded proteins into Lewy bodies in the neurons. Collectively, the main motor symptoms are also known as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alzheimer's Disease
Alzheimer's disease (AD) is a neurodegeneration, neurodegenerative disease that usually starts slowly and progressively worsens. It is the cause of 60–70% of cases of dementia. The most common early symptom is difficulty in short-term memory, remembering recent events. As the disease advances, symptoms can include primary progressive aphasia, problems with language, Orientation (mental), disorientation (including easily getting lost), mood swings, loss of motivation, self-neglect, and challenging behaviour, behavioral issues. As a person's condition declines, they often withdraw from family and society. Gradually, bodily functions are lost, ultimately leading to death. Although the speed of progression can vary, the typical life expectancy following diagnosis is three to nine years. The cause of Alzheimer's disease is poorly understood. There are many environmental and genetic risk factors associated with its development. The strongest genetic risk factor is from an alle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurodegenerative Disease
A neurodegenerative disease is caused by the progressive loss of structure or function of neurons, in the process known as neurodegeneration. Such neuronal damage may ultimately involve cell death. Neurodegenerative diseases include amyotrophic lateral sclerosis, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, multiple system atrophy, and prion diseases. Neurodegeneration can be found in the brain at many different levels of neuronal circuitry, ranging from molecular to systemic. Because there is no known way to reverse the progressive degeneration of neurons, these diseases are considered to be incurable; however research has shown that the two major contributing factors to neurodegeneration are oxidative stress and inflammation. Biomedical research has revealed many similarities between these diseases at the subcellular level, including atypical protein assemblies (like proteinopathy) and induced cell death. These similarities suggest that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaperones (biology)
In molecular biology, molecular chaperones are proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes. There are a number of classes of molecular chaperones, all of which function to assist large proteins in proper protein folding during or after synthesis, and after partial denaturation. Chaperones are also involved in the translocation of proteins for proteolysis. The first molecular chaperones discovered were a type of assembly chaperones which assist in the assembly of nucleosomes from folded histones and DNA. One major function of molecular chaperones is to prevent the aggregation of misfolded proteins, thus many chaperone proteins are classified as heat shock proteins, as the tendency for protein aggregation is increased by heat stress. The majority of molecular chaperones do not convey any steric information for protein folding, and instead assist in protein folding by binding to and stabilizing folding intermedia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
