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Mitogen-activated Protein Kinase
A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of serine/threonine-specific protein kinases involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammatory cytokines. They regulate cell functions including proliferation, gene expression, differentiation, mitosis, cell survival, and apoptosis. MAP kinases are found in eukaryotes only, but they are fairly diverse and encountered in all animals, fungi and plants, and even in an array of unicellular eukaryotes. MAPKs belong to the CMGC (CDK/MAPK/GSK3/CLK) kinase group. The closest relatives of MAPKs are the cyclin-dependent kinases (CDKs). Discovery The first mitogen-activated protein kinase to be discovered was ERK1 (MAPK3) in mammals. Since ERK1 and its close relative ERK2 (MAPK1) are both involved in growth factor signaling, the family was termed "mitogen-activated". With the discovery of other members, even from distant organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serine/threonine-specific Protein Kinase
A serine/threonine protein kinase () is a kinase enzyme, in particular a protein kinase, that phosphorylation, phosphorylates the hydroxyl, OH group of the amino acid, amino-acid residues serine or threonine, which have similar side chains. At least 350 of the 500+ human protein kinases are serine/threonine kinases (STK). In enzymology, the term ''serine/threonine protein kinase'' describes a class of enzymes in the family of transferases, that transfer phosphates to the oxygen atom of a serine or threonine side chain in proteins. This process is called phosphorylation. Protein phosphorylation in particular plays a significant role in a wide range of cellular processes and is a very important post-translational modification. The chemical reaction performed by these enzymes can be written as :ATP + a protein \rightleftharpoons ADP + a phosphoprotein Thus, the two substrate (biochemistry), substrates of this enzyme are adenosine triphosphate, ATP and a protein, whereas its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
P38 Mitogen-activated Protein Kinases
p38 mitogen-activated protein kinases are a class of mitogen-activated protein kinases (MAPKs) that are responsive to stress stimuli, such as cytokines, ultraviolet irradiation, heat shock, and osmotic shock, and are involved in cell differentiation, apoptosis and autophagy. Persistent activation of the p38 MAPK pathway in muscle satellite cells (muscle stem cells) due to ageing, impairs muscle regeneration. p38 MAP Kinase (MAPK), also called RK or CSBP (Cytokinin Specific Binding Protein), is the mammalian orthologue of the yeast Hog1p MAP kinase, which participates in a signaling cascade controlling cellular responses to cytokines and stress. Four p38 MAP kinases, p38-α ( MAPK14), -β ( MAPK11), -γ ( MAPK12 / ERK6), and -δ ( MAPK13 / SAPK4), have been identified. Similar to the SAPK/JNK pathway, p38 MAP kinase is activated by a variety of cellular stresses including osmotic shock, inflammatory cytokines, lipopolysaccharides (LPS), ultraviolet light, and growth fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a conditionally essential amino acid with a polar side group. The word "tyrosine" is from the Greek ''tyrós'', meaning ''cheese'', as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese. It is called tyrosyl when referred to as a functional group or side chain. While tyrosine is generally classified as a hydrophobic amino acid, it is more hydrophilic than phenylalanine. It is encoded by the codons UAC and UAU in messenger RNA. The one-letter symbol Y was assigned to tyrosine for being alphabetically nearest of those letters available. Note that T was assigned to the structurally simpler threonine, U was avoided for its similarity with V for valine, W was assigned to tryptophan, while X was reserved for undetermined or atypical amino acids. The mnemonic t''Y''rosine was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Threonine
Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form when dissolved in water), a carboxyl group (which is in the deprotonated −COO− form when dissolved in water), and a side chain containing a hydroxyl group, making it a polar, uncharged amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Threonine is synthesized from aspartate in bacteria such as ''E. coli''. It is encoded by all the codons starting AC (ACU, ACC, ACA, and ACG). Threonine sidechains are often hydrogen bonded; the most common small motifs formed are based on interactions with serine: ST turns, ST motifs (often at the beginning of alpha helices) and ST staples (usually at the middle of alpha helices). Modifications The threonine residue is susceptible to numerous posttranslational modifications. The hydroxyl side-chain can und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ERK5
Mitogen-activated protein kinase 7 also known as MAP kinase 7 is an enzyme that in humans is encoded by the ''MAPK7'' gene. Function MAPK7 is a member of the MAP kinase family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as proliferation, differentiation, transcription regulation and development. MAPK7 is also referred to as ERK5 or BMK (Big MAPK) due to its large size which is around double that of other ERKs. This kinase is specifically activated by mitogen-activated protein kinase kinase 5 ( MAP2K5/ MEK5). It is involved in the downstream signaling processes of various receptor molecules including receptor tyrosine kinases, and G protein-coupled receptors. In response to extracellular signals, this kinase translocates to the cell nucleus, where it regulates gene expression by phosphorylating, and activating different transcription factors. Four alternatively spliced transcript va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activation Loop
In molecular biology, an intrinsically disordered protein (IDP) is a protein that lacks a fixed or ordered three-dimensional structure, typically in the absence of its macromolecular interaction partners, such as other proteins or RNA. IDPs range from fully unstructured to partially structured and include random coil, molten globule-like aggregates, or flexible linkers in large multi- domain proteins. They are sometimes considered as a separate class of proteins along with globular, fibrous and membrane proteins. IDPs are a very large and functionally important class of proteins. They are most numerous in eukaryotes, with an estimated 30-40% of residues in the eukaryotic proteome located in disordered regions. Disorder is present in around 70% of proteins, either in the form of disordered tails or flexible linkers. Proteins can also be entirely disordered and lack a defined secondary and/or tertiary structure. Their discovery has disproved the idea that three-dimensional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allostery
In the fields of biochemistry and pharmacology an allosteric regulator (or allosteric modulator) is a substance that binds to a site on an enzyme or Receptor (biochemistry), receptor distinct from the active site, resulting in a conformational change that alters the protein's activity, either enhancing or inhibiting its function. In contrast, substances that bind directly to an enzyme's active site or the binding site of the endogenous ligand of a receptor are called orthosteric regulators or modulators. The site to which the effector binds is termed the ''allosteric site'' or ''regulatory site''. Allosteric sites allow effectors to bind to the protein, often resulting in a conformational change and/or a change in protein dynamics. Effectors that enhance the protein's activity are referred to as ''allosteric activators'', whereas those that decrease the protein's activity are called ''allosteric inhibitors''. Allosteric regulations are a natural example of control loops, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conformational Change
In biochemistry, a conformational change is a change in the shape of a macromolecule, often induced by environmental factors. A macromolecule is usually flexible and dynamic. Its shape can change in response to changes in its environment or other factors; each possible shape is called a conformation, and a transition between them is called a ''conformational change''. Factors that may induce such changes include temperature, pH, voltage, light in chromophores, concentration of ions, phosphorylation, or the binding of a ligand. Transitions between these states occur on a variety of length scales (tenths of Å to nm) and time scales (ns to s), and have been linked to functionally relevant phenomena such as allosteric signaling and enzyme catalysis. Laboratory analysis Many biophysical techniques such as crystallography, NMR, electron paramagnetic resonance (EPR) using spin label techniques, circular dichroism (CD), hydrogen exchange, and FRET can be used to study macromo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Dynamics
In molecular biology, proteins are generally thought to adopt unique structures determined by their amino acid sequences. However, proteins are not strictly static objects, but rather populate ensembles of (sometimes similar) conformations. Transitions between these states occur on a variety of length scales (tenths of angstroms to nm) and time scales (ns to s), and have been linked to functionally relevant phenomena such as allosteric signaling and enzyme catalysis. The study of protein dynamics is most directly concerned with the transitions between these states, but can also involve the nature and equilibrium populations of the states themselves. These two perspectives— kinetics and thermodynamics, respectively—can be conceptually synthesized in an " energy landscape" paradigm: highly populated states and the kinetics of transitions between them can be described by the depths of energy wells and the heights of energy barriers, respectively. Local flexibility: atoms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inflammatory Cytokine
An inflammatory cytokine or proinflammatory cytokine is a type of signaling molecule (a cytokine) that is secreted from immune cells like helper T cells (Th) and macrophages, and certain other cell types that promote inflammation. They include interleukin-1 (IL-1), IL-6, IL-12, and IL-18, tumor necrosis factor alpha (TNF-α), interferon gamma (IFNγ), and granulocyte-macrophage colony stimulating factor (GM-CSF) and play an important role in mediating the innate immune response. Inflammatory cytokines are predominantly produced by and involved in the upregulation of inflammatory reactions. Excessive chronic production of inflammatory cytokines contribute to inflammatory diseases, that have been linked to different diseases, such as atherosclerosis and cancer. Dysregulation has also been linked to depression and other neurological diseases. A balance between proinflammatory and anti-inflammatory cytokines is necessary to maintain health. Aging and exercise also play a role i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellular Stress Response
Cellular stress response is the wide range of molecular changes that cells undergo in response to environmental stressors, including extremes of temperature, exposure to toxins, and mechanical damage. Cellular stress responses can also be caused by some viral infections. The various processes involved in cellular stress responses serve the adaptive purpose of protecting a cell against unfavorable environmental conditions, both through short term mechanisms that minimize acute damage to the cell's overall integrity, and through longer term mechanisms which provide the cell a measure of resiliency against similar adverse conditions. General characteristics Cellular stress responses are primarily mediated through what are classified as ''stress proteins''. Stress proteins often are further subdivided into two general categories: those that only are activated by stress, or those that are involved both in stress responses and in normal cellular functioning. The essential character o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
