Synaptophysin

Synaptophysin, also known as the major synaptic vesicle protein p38, is a protein that in humans is encoded by the SYP gene.^[5][6]

SYP
Identifiers
Aliases	SYP, MRX96, MRXsynaptophysin, XLID96
External IDs	OMIM: 313475; MGI: 98467; HomoloGene: 2391; GeneCards: SYP; OMA:SYP - orthologs
Gene location (Human) Chr. X chromosome (human)[1] Band Xp11.23 Start 49,187,815 bp[1] End 49,200,218 bp[1]
Gene location (Mouse) Chr. X chromosome (mouse)[2] Band X A1.1|X 3.44 cM Start 7,504,710 bp[2] End 7,519,495 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right hemisphere of cerebellum right frontal lobe prefrontal cortex Brodmann area 9 anterior cingulate cortex amygdala anterior pituitary Brodmann area 10 nucleus accumbens C1 segment Top expressed in neural layer of retina dentate gyrus of hippocampal formation granule cell medial dorsal nucleus superior frontal gyrus subiculum cerebellar cortex medial geniculate nucleus dorsomedial hypothalamic nucleus medial vestibular nucleus habenula More reference expression data BioGPS More reference expression data
Gene ontology Molecular function SH2 domain binding protein self-association cholesterol binding identical protein binding syntaxin-1 binding Cellular component integral component of membrane membrane synaptic vesicle synapse excitatory synapse synaptic vesicle membrane presynaptic active zone cell junction terminal bouton integral component of synaptic vesicle membrane neuron projection neuron projection terminus presynaptic membrane cytoplasmic vesicle neuromuscular junction Schaffer collateral - CA1 synapse perinuclear region of cytoplasm Biological process cellular response to organic substance regulation of long-term neuronal synaptic plasticity endocytosis regulation of opioid receptor signaling pathway regulation of short-term neuronal synaptic plasticity synaptic vesicle membrane organization regulation of neuronal synaptic plasticity synaptic vesicle maturation synaptic vesicle endocytosis regulation of synaptic vesicle exocytosis Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 6855 20977 Ensembl ENSG00000102003 ENSMUSG00000031144 UniProt P08247 Q62277 RefSeq (mRNA) NM_003179 NM_009305 RefSeq (protein) NP_003170 NP_033331 Location (UCSC) Chr X: 49.19 – 49.2 Mb Chr X: 7.5 – 7.52 Mb PubMed search [3] [4]
Wikidata
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Gene

The gene is located on the short arm of X chromosome (Xp11.23-p11.22). It is 12,406 bases in length and lies on the minus strand.

Tissue distribution

It is expressed in neuroendocrine cells and in virtually all neurons in the brain and spinal cord that participate in synaptic transmission.

Structure

The protein is a synaptic vesicle glycoprotein with four transmembrane domains weighing 38 kDa.

Function

The exact function of the protein is unknown: it interacts with the essential synaptic vesicle protein synaptobrevin, but when the synaptophysin gene is experimentally inactivated in animals, they still develop and function normally.^[7] Recent research has shown, however, that elimination of synaptophysin in mice creates behavioral changes such as increased exploratory behavior, impaired object novelty recognition, and reduced spatial learning.^[8]

Clinical significance

Biomarker

It acts as a marker for neuroendocrine tumors, and its ubiquity at the synapse has led to the use of synaptophysin immunostaining for quantification of synapses.^[9]

Using immunohistochemistry, synaptophysin can be demonstrated in a range of neural and neuroendocrine tissues,^[10] including cells of the adrenal medulla and pancreatic islets. As a specific marker for these tissues, it can be used to identify tumours arising from them, such as neuroblastoma, retinoblastoma, phaeochromocytoma, carcinoid, small-cell carcinoma, medulloblastoma and medullary thyroid carcinoma, among others. Diagnostically, it is often used in combination with chromogranin A.^[11]

X-linked intellectual disability

Mutations in this gene have been implicated in X-linked intellectual disability.^[12]

Interactions

Synaptophysin has been shown to interact with AP1G1^[13] and SIAH2.^[14]

See also

• List of human genes
• Merkel-cell carcinoma - although origin of this tumor is unclear, it does express synaptophysin