词条 | SEMA3A |
释义 |
FunctionThe SEMA3A gene is a member of the semaphorin family and encodes a protein with an Ig-like C2-type (immunoglobulin-like) domain, a PSI domain and a Sema domain. This secreted Sema3A protein can function as either a chemorepulsive agent, inhibiting axonal outgrowth, or as a chemoattractive agent, stimulating the growth of apical dendrites. In both cases, the protein is vital for normal neuronal pattern development.[3] Semaphorin-3A is secreted by neurons and surrounding tissue to guide migrating cells and axons in the developing nervous system. Axon pathfinding is the process by which neurons follow very precise paths, sends out axons, and react to specific chemical environments to reach the correct endpoint. The guidance is critical for the precise formation of neurons and the surrounding vasculature. Guidance cues, such as Sema3A, induce the collapse and paralysis of neuronal growth cones during development of the nervous system. This guidance cue for axons of neurons is signaled through receptor complexes containing Neuropilin-1 (NRP1) and a co-receptor.[4][5][6] One of the first identified intracellular messenger required for the growth cone-collapse induced by Sema3A is the CRMP protein called CRMP2. In addition to its role in the nervous system, Sema3A also acts as an inhibitor of angiogenesis, the process by which new blood vessels develop.[7] Clinical significanceThe protein Sema3A is highly expressed in scar tissue after traumatic central nervous system injuries, such as spinal cord injury. Sema3A, and the other class 3 semaphorins, contributes to the failure of neuronal regeneration after CNS injury by regulating axonal re-growth, re-myelination, re-vascularisation, and the immune response.[8] Increased expression of Sema3A is associated with schizophrenia and is seen in a variety of human tumor cell lines. Also, aberrant release of this protein is associated with the progression of Alzheimer's disease.[3][9] Additionally, the terminal Schwann cells of ALS mice (SOD1 mutant) express Sema3A at fast-fatigable fiber neuromuscular junctions greater than wild-type mice.[10] This expression is greatest pre-symptomatically corresponding to ALS progression in which fast-fatigable fiber denervation precedes clinical symptoms.[11] Because Sema3A is involved in growth cone collapse and axon pruning and repulsion, it potentially holds a causal relationship to synaptic weakening and denervation that precedes motor neuron apoptosis in ALS.[10] References1. ^{{cite journal | vauthors = Kolodkin AL, Matthes DJ, Goodman CS | title = The semaphorin genes encode a family of transmembrane and secreted growth cone guidance molecules | journal = Cell | volume = 75 | issue = 7 | pages = 1389–99 | date = Jan 1994 | pmid = 8269517 | pmc = | doi = 10.1016/0092-8674(93)90625-Z }} 2. ^{{cite journal | vauthors = Püschel AW, Adams RH, Betz H | title = Murine semaphorin D/collapsin is a member of a diverse gene family and creates domains inhibitory for axonal extension | journal = Neuron | volume = 14 | issue = 5 | pages = 941–8 | date = Jun 1995 | pmid = 7748561 | pmc = | doi = 10.1016/0896-6273(95)90332-1 }} 3. ^1 2 {{cite web | title = Entrez Gene: SEMA3A sema domain, immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin) 3A| url = https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=10371| accessdate = }} 4. ^{{cite journal | vauthors = Moret F, Renaudot C, Bozon M, Castellani V | title = Semaphorin and neuropilin co-expression in motoneurons sets axon sensitivity to environmental semaphorin sources during motor axon pathfinding | journal = Development | volume = 134 | issue = 24 | pages = 4491–501 | date = December 2007 | pmid = 18039974 | doi = 10.1242/dev.011452 | url = }} 5. ^{{cite journal | vauthors = Vieira JM, Schwarz Q, Ruhrberg C | title = Selective requirements for NRP1 ligands during neurovascular patterning | journal = Development | volume = 134 | issue = 10 | pages = 1833–43 | date = May 2007 | pmid = 17428830 | pmc = 2702678 | doi = 10.1242/dev.002402 }} 6. ^{{cite journal | vauthors = Sharma A, Verhaagen J, Harvey AR | title = Receptor complexes for each of the Class 3 Semaphorins | journal = Frontiers in Cellular Neuroscience | volume = 6 | pages = 28 | pmid = 22783168 | pmc = 3389612 | doi = 10.3389/fncel.2012.00028 | year=2012}} 7. ^{{cite journal | vauthors = Maione F, Molla F, Meda C, Latini R, Zentilin L, Giacca M, Seano G, Serini G, Bussolino F, Giraudo E | title = Semaphorin 3A is an endogenous angiogenesis inhibitor that blocks tumor growth and normalizes tumor vasculature in transgenic mouse models. | journal = The Journal of Clinical Investigation | volume = 119 | issue = 11 | pages = 3356–72 | pmid = 19809158 | doi = 10.1172/JCI36308 | pmc=2769187 | year=2009}} 8. ^{{Cite journal|last=Mecollari|first=V|last2=Nieuwenhuis|first2=B|last3=Verhaagen|first3=J|date=2014|title=A perspective on the role of class III semaphorin signaling in central nervous system trauma|journal=Frontiers in Cellular Neuroscience|volume=8|pages=328|doi=10.3389/fncel.2014.00328|pmc=4209881|pmid=25386118}} 9. ^{{cite journal | vauthors = Good PF, Alapat D, Hsu A, Chu C, Perl D, Wen X, Burstein DE, Kohtz DS | title = A role for semaphorin 3A signaling in degeneration of hippocampal neurons during Alzheimer's disease | journal = J. Neurochem. | volume = 91 | issue = 3 | pages = 716–36 | date = November 2004 | pmid = 15485501 | doi = 10.1111/j.1471-4159.2004.02766.x }} 10. ^1 {{cite journal | vauthors = De Winter F, Vo T, Stam FJ, Wisman LA, Bär PR, Niclou SP, van Muiswinkel FL, Verhaagen J | title = The expression of the chemorepellent Semaphorin 3A is selectively induced in terminal Schwann cells of a subset of neuromuscular synapses that display limited anatomical plasticity and enhanced vulnerability in motor neuron disease | journal = Mol. Cell. Neurosci. | volume = 32 | issue = 1–2 | pages = 102–17 | year = 2006 | pmid = 16677822 | doi = 10.1016/j.mcn.2006.03.002 }} 11. ^{{cite journal | vauthors = Frey D, Schneider C, Xu L, Borg J, Spooren W, Caroni P | title = Early and selective loss of neuromuscular synapse subtypes with low sprouting competence in motoneuron diseases | journal = J. Neurosci. | volume = 20 | issue = 7 | pages = 2534–42 | date = April 2000 | pmid = 10729333 | doi = 10.1523/JNEUROSCI.20-07-02534.2000}} Further reading{{refbegin | 2}}
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