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Plexins
A plexin is a protein which acts as a receptor for semaphorin family signaling proteins. It is classically known for its expression on the surface of axon growth cones and involvement in signal transduction to steer axon growth away from the source of semaphorin. Plexin also has implications in development of other body systems by activating GTPase enzymes to induce a number of intracellular biochemical changes leading to a variety of downstream effects. Structure Extracellular All plexins have an extracellular SEMA domain at their N-terminus. This is a structural motif common among all semaphorins and plexins and is responsible for this binding of semaphorin dimers, which are the native conformation for these ligands in vivo. This is followed by alternating plexin, semaphorin, and integrin (PSI) domains and immunoglobulin-like, plexin, and transcription factors (IPT) domains. Each of these is named for the proteins in which their structure is conserved. Collectively, the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semaphorin
Semaphorins are a class of secreted and membrane proteins that were originally identified as axonal growth cone guidance molecules. They primarily act as short-range inhibitory signals and signal through multimeric receptor complexes. Semaphorins are usually cues to deflect axons from inappropriate regions, especially important in the neural system development. The major class of proteins that act as their receptors are called plexins, with neuropilins as their co-receptors in many cases. The main receptors for semaphorins are plexins, which have established roles in regulating Rho-family GTPases. Recent work shows that plexins can also influence R-Ras, which, in turn, can regulate integrins. Such regulation is probably a common feature of semaphorin signalling and contributes substantially to our understanding of semaphorin biology. Every semaphorin is characterised by the expression of a specific region of about 500 amino acids called the sema domain. Semaphorins were named a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLXNB1
Plexin B1 is a protein of the plexin family that in humans is encoded by the ''PLXNB1'' gene. Function Within neural tissues, the plexin family serves as transmembrane receptors for Semaphorins. Outside of neural tissues, Plexin B1 is implicated in the control of cell migration. Interactions PLXNB1 has been shown to interact with ARHGEF12, Rnd1 and ARHGEF11 Rho guanine nucleotide exchange factor 11 is a protein that in humans is encoded by the ''ARHGEF11'' gene. This protein is also called RhoGEF11 or PDZ-RhoGEF. Function Rho guanine nucleotide exchange factor 11 is guanine nucleotide exchange fa .... References * Chapoval SP, Hritzo M, Qi X, Tamagnone L, Golding A and Keegan AD. "Semaphorin 4A Stabilizes Human Regulatory T Cell Phenotype via Plexin B1". ImmunoHorizons, February 1, 2019, 3 (2) 71-87; Further reading * * * * * * * * * * * * * * * * External links * {{gene-3-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLXNA3
Plexin-A3 is a protein that in humans is encoded by the ''PLXNA3'' 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 b .... References Further reading * * * * * * * {{gene-X-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLXNA2
Plexin-A2 is a protein that in humans is coded by the ''PLXNA2'' gene. This gene encodes a member of the plexin-A family of semaphorin co-receptors. Semaphorins are a large family of secreted or membrane-bound proteins that mediate repulsive effects on axon pathfinding during nervous system development. A subset of semaphorins are recognized by plexin-A/neuropilin transmembrane receptor complexes, triggering a cellular signal transduction cascade that leads to axon repulsion. This plexin-A family member is thought to transduce signals from semaphorin-3A and -3C. In some studies, the PLXNA2 gene is associated with schizophrenia. and anxiety. PLXNA2 is a candidate gene for intellectual disability and possibly facial dysmorphism and congenital heart disease References Further reading * * * * * * * * * * * {{gene-1-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PLXNA1
Plexin-A1 is a protein that in humans is encoded by the ''PLXNA1'' gene. Interactions Plexin A1 has been shown to interact with AKT1 RAC(Rho family)-alpha serine/threonine-protein kinase is an enzyme that in humans is encoded by the ''AKT1'' gene. This enzyme belongs to the AKT subfamily of serine/threonine kinases that contain SH2 (Src homology 2-like) protein domains. It .... References Further reading * * * * * * * * * * * * * * {{gene-3-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology Modeling
Homology modeling, also known as comparative modeling of protein, refers to constructing an atomic-resolution model of the "''target''" protein from its amino acid sequence and an experimental three-dimensional structure of a related homologous protein (the "''template''"). Homology modeling relies on the identification of one or more known protein structures likely to resemble the structure of the query sequence, and on the production of an alignment that maps residues in the query sequence to residues in the template sequence. It has been seen that protein structures are more conserved than protein sequences amongst homologues, but sequences falling below a 20% sequence identity can have very different structure. Evolutionarily related proteins have similar sequences and naturally occurring homologous proteins have similar protein structure. It has been shown that three-dimensional protein structure is evolutionarily more conserved than would be expected on the basis of sequence ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclic Guanosine Monophosphate
Cyclic guanosine monophosphate (cGMP) is a cyclic nucleotide derived from guanosine triphosphate (GTP). cGMP acts as a second messenger much like cyclic AMP. Its most likely mechanism of action is activation of intracellular protein kinases in response to the binding of membrane-impermeable peptide hormones to the external cell surface. Synthesis Guanylate cyclase (GC) catalyzes cGMP synthesis. This enzyme converts GTP to cGMP. Peptide hormones such as the atrial natriuretic factor activate membrane-bound GC, while soluble GC (sGC) is typically activated by nitric oxide to stimulate cGMP synthesis. sGC can be inhibited by ODQ (1H- ,2,4xadiazolo ,3-auinoxalin-1-one). Functions cGMP is a common regulator of ion channel conductance, glycogenolysis, and cellular apoptosis. It also relaxes smooth muscle tissues. In blood vessels, relaxation of vascular smooth muscles leads to vasodilation and increased blood flow. At presynaptic terminals in the striatum, cGMP control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Messenger
Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form or cell signaling, encompassing both first messengers and second messengers, are classified as autocrine, juxtacrine, paracrine, and endocrine depending on the range of the signal.) Second messengers trigger physiological changes at cellular level such as proliferation, differentiation, migration, survival, apoptosis and depolarization. They are one of the triggers of intracellular signal transduction cascades. Examples of second messenger molecules include cyclic AMP, cyclic GMP, inositol triphosphate, diacylglycerol, and calcium. First messengers are extracellular factors, often hormones or neurotransmitters, such as epinephrine, growth hormone, and serotonin. Because peptide hormones and neurotransmitters typically are biochemically hydrophilic molecules, these first messenge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small GTPase
Small GTPases (), also known as small G-proteins, are a family of hydrolase enzymes that can bind and hydrolyze guanosine triphosphate (GTP). They are a type of G-protein found in the cytosol that are homologous to the alpha subunit of heterotrimeric G-proteins, but unlike the alpha subunit of G proteins, a small GTPase can function independently as a hydrolase enzyme to bind to and hydrolyze a guanosine triphosphate (GTP) to form guanosine diphosphate (GDP). The best-known members are the Ras GTPases and hence they are sometimes called Ras subfamily GTPases. A typical G-protein is active when bound to GTP and inactive when bound to GDP (i.e. when the GTP is hydrolyzed to GDP). The GDP can be then replaced by free GTP. Therefore, a G-protein can be switched on and off. GTP hydrolysis is accelerated by GTPase activating proteins (GAPs), while GTP exchange is catalyzed by guanine nucleotide exchange factors (GEFs). Activation of a GEF typically activates its cognate G-protein, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rnd (GTPase)
Rnd is a subclass of the Rho family of GTPases and includes: *Rnd1 *Rnd2 *Rnd3 (also called RhoE) Functions include downregulation of stress fibres and focal adhesions. See also *Rho family of GTPases The Rho family of GTPases is a family of small (~21 kDa) signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are foun ... References EC 3.6.5 {{3.6-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
