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Calcium-binding Protein
Calcium-binding proteins are proteins that participate in calcium cell signaling pathways by binding to Ca2+, the calcium ion that plays an important role in many cellular processes. Calcium-binding proteins have specific domains that bind to calcium and are known to be heterogeneous. One of the functions of calcium binding proteins is to regulate the amount of free (unbound) Ca2+ in the cytosol of the cell. The cellular regulation of calcium is known as calcium homeostasis. Types Many different calcium-binding proteins exist, with different cellular and tissue distribution and involvement in specific functions. Calcium binding proteins also serve an important physiological role for cells. The most ubiquitous Ca2+-sensing protein, found in all eukaryotic organisms including yeasts, is calmodulin. Intracellular storage and release of Ca2+ from the sarcoplasmic reticulum is associated with the high-capacity, low-affinity calcium-binding protein calsequestrin. Calretinin is anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Family
A gene family is a set of several similar genes, formed by duplication of a single original gene, and generally with similar biochemical functions. One such family are the genes for human hemoglobin subunits; the ten genes are in two clusters on different chromosomes, called the α-globin and β-globin loci. These two gene clusters are thought to have arisen as a result of a precursor gene being duplicated approximately 500 million years ago. Genes are categorized into families based on shared nucleotide or protein sequences. Phylogenetic techniques can be used as a more rigorous test. The positions of exons within the coding sequence can be used to infer common ancestry. Knowing the sequence of the protein encoded by a gene can allow researchers to apply methods that find similarities among protein sequences that provide more information than similarities or differences among DNA sequences. If the genes of a gene family encode proteins, the term ''protein family'' is often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troponin
Troponin, or the troponin complex, is a complex of three regulatory proteins (troponin C, troponin I, and troponin T) that are integral to muscle contraction in skeletal muscle and cardiac muscle, but not smooth muscle. Measurements of cardiac-specific troponins I and T are extensively used as diagnostic and prognostic indicators in the management of myocarditis, myocardial infarction and acute coronary syndrome. Blood troponin levels may be used as a diagnosis, diagnostic marker for stroke or other myocardial injury that is ongoing, although the sensitivity of this measurement is low. Function Troponin is attached to the protein tropomyosin and lies within the groove between actin filaments in muscle tissue. In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing contraction. When the muscle cell is stimulated to contract by an action potential, calcium channels open in the sarcoplasmic membrane and release calcium into the sarcoplas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calsequestrin
Calsequestrin is a calcium-binding protein that acts as a calcium buffer within the sarcoplasmic reticulum. The protein helps hold calcium in the cisterna of the sarcoplasmic reticulum after a muscle contraction, even though the concentration of calcium in the sarcoplasmic reticulum is much higher than in the cytosol. It also helps the sarcoplasmic reticulum store an extraordinarily high amount of calcium ions. Each molecule of calsequestrin can bind 18 to 50 Ca2+ ions. Sequence analysis has suggested that calcium is not bound in distinct pockets via EF-hand motifs, but rather via presentation of a charged protein surface. Two forms of calsequestrin have been identified. The cardiac form Calsequestrin-2 (CASQ2) is present in cardiac and slow skeletal muscle and the fast skeletal form Calsequestrin-1(CASQ1) is found in fast skeletal muscle. The release of calsequestrin-bound calcium (through a calcium release channel) triggers muscle contraction. The active protein is not high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calbindin
Calbindins are three different calcium-binding proteins: calbindin 1, calbindin, calretinin and S100G. They were originally described as vitamin D-dependent calcium-binding proteins in the intestine and kidney of chicks and mammals. They are now classified in different protein family, subfamilies as they differ in the number of Ca2+ binding EF hands. Calbindin 1 Calbindin 1 or simply calbindin was first shown to be present in the intestine in birds and then found in the mammalian kidney. It is also expressed in a number of neuronal and endocrine cells, particularly in the cerebellum. It is a 28 kDa protein encoded in humans by the ''CALB1'' gene. Calbindin contains 4 active calcium-binding protein domain, domains, and 2 modified domains that have lost their calcium-binding capacity. Calbindin acts as a calcium buffer and calcium sensor and can hold four Ca2+ in the EF-hands of loops EF1, EF3, EF4 and EF5. The structure of rat calbindin was originally solved by nuclear magnetic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calretinin
Calretinin, also known as calbindin 2 (formerly 29 kDa calbindin), is a calcium-binding protein involved in calcium signaling. In humans, the calretinin protein is encoded by the ''CALB2'' gene. Function This gene encodes an intracellular calcium-binding protein belonging to the troponin C superfamily. Members of this protein family have six EF-hand domains which bind calcium. This protein plays a role in diverse cellular functions, including message targeting and intracellular calcium buffering. Calretinin is abundantly expressed in neurons including retina (which gave it the name) and cortical interneurons. Expression was found in different neurons than that of the similar vitamin D-dependent calcium-binding protein, calbindin-28kDa. Calretinin has an important role as a modulator of neuronal excitability including the induction of long-term potentiation. Loss of expression of calretinin in hippocampal interneurons has been suggested to be relevant in temporal lobe epil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Of The National Academy Of Sciences
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Sciences, published since 1915, and publishes original research, scientific reviews, commentaries, and letters. According to ''Journal Citation Reports'', the journal has a 2022 impact factor of 9.4. ''PNAS'' is the second most cited scientific journal, with more than 1.9 million cumulative citations from 2008 to 2018. In the past, ''PNAS'' has been described variously as "prestigious", "sedate", "renowned" and "high impact". ''PNAS'' is a delayed open-access journal, with an embargo period of six months that can be bypassed for an author fee ( hybrid open access). Since September 2017, open access articles are published under a Creative Commons license. Since January 2019, ''PNAS'' has been online-only, although print issues are available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage-dependent Potassium Channel
Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state. Classification Alpha subunits Alpha subunits form the actual conductance pore. Based on sequence homology of the hydrophobic transmembrane cores, the alpha subunits of voltage-gated potassium channels are grouped into 12 classes. These are labeled Kvα1-12. The following is a list of the 40 known human voltage-gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme: Delayed rectifier slowly inactivating or non-inactivating *Kvα1.x - Shaker-related: Kv1.1 ( KCNA1), Kv1.2 (KCNA2), Kv1.3 (KCNA3), Kv1.5 ( KCNA5), Kv1.6 ( KCNA6), Kv1.7 ( KCNA7), Kv1.8 ( KCNA10) *Kvα2.x - Shab-related: Kv2.1 ( KCNB1), Kv2.2 ( KCNB2) *Kv� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuron
A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural network in the nervous system. They are located in the nervous system and help to receive and conduct impulses. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap. Neurons are the main components of nervous tissue in all Animalia, animals except sponges and placozoans. Plants and fungi do not have nerve cells. Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period. Predecessors of neurons were the peptidergic secretory cells. They eventually ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calexcitin
Calexcitin is a calcium-binding protein first isolated from the sea snail ''Hermissenda crassicornis''. It is upregulated following Pavlovian conditioning Classical conditioning (also respondent conditioning and Pavlovian conditioning) is a behavioral procedure in which a biologically potent stimulus (e.g. food, a puff of air on the eye, a potential rival) is paired with a neutral stimulus (e.g. .... Calexcitin has four EF-hand motifs that possess different functions while the fourth one is nonfunctional. Calexcitin has the tendency to regulate K+ channels. In addition, Calexcitin also shows a sign of GTP binding protein in which that binds to Ca2+. Calexcitin is neuronal-specific and becomes phosphorylated and upregulated in learning of association. EF-hand motifs Calexcitin which has four EF-hand motifs. The first three function in the binding metal ions which are from EF-1 to EF-3. EF-1 and EF-2 contain the proclivity into binding with Mg2+ and Ca2+. However, the EF-3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casein
Casein ( , from Latin ''caseus'' "cheese") is a family of related phosphoproteins (CSN1S1, αS1, aS2, CSN2, β, K-casein, κ) that are commonly found in mammalian milk, comprising about 80% of the proteins in cow's milk and between 20% and 60% of the proteins in breast milk, human milk. Sheep's milk, Sheep and cow milk have a higher casein content than other types of milk with human milk having a particularly low casein content. Casein is the primary emulsifier in milk, that is, it helps in mixing oils, fats, and water in milk. Casein has a wide variety of uses, from being a major component of cheese, to use as a food additive. The most common form of casein is sodium caseinate (historically called nutrose), which is a very efficient emulsifier. Casein is secreted into milk from mammary cells in the form of colloidal casein micelles, a type of biomolecular condensate. As a food source, casein supplies amino acids, carbohydrates, and two essential elements, calcium and phosphoru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
