Synaptophysin

Synaptophysin
Identifiers
Symbols	SYP ; MRX96; MRXSYP
External IDs	OMIM: 313475 MGI: 98467 HomoloGene: 2391 GeneCards: SYP Gene
Gene ontology Molecular function • transporter activity • cholesterol binding • SH2 domain binding • identical protein binding • protein self-association Cellular component • synaptic vesicle • cell junction • integral component of synaptic vesicle membrane • synaptic vesicle membrane • presynaptic membrane • neuron projection • neuron projection terminus • excitatory synapse Biological process • endocytosis • synaptic vesicle maturation • regulation of neuronal synaptic plasticity • regulation of long-term neuronal synaptic plasticity • regulation of short-term neuronal synaptic plasticity • synaptic vesicle membrane organization • cellular response to organic substance • regulation of opioid receptor signaling pathway Sources: Amigo / QuickGO
RNA expression pattern
More reference expression data
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: 7.64 – 7.65 Mb
PubMed search	[1]	[2]

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

Genomics

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 Crick (minus) strand. The encoded protein has 313 amino acids with a predicted molecular weight of 33.845 kDa.

Molecular biology

The protein is a synaptic vesicle glycoprotein with four transmembrane domains weighing 38kDa. It is present in neuroendocrine cells and in virtually all neurons in the brain and spinal cord that participate in synaptic transmission. 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.

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. 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.

Clinical importance

This gene has been implicated in X linked mental retardation.

Using immunohistochemistry, synaptophysin can be demonstrated in a range of neural and neuroendocrine tissues, 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.

See also

• List of human genes

Interactions

Synaptophysin has been shown to interact with AP1G1 and SIAH2.

External links

• Synaptophysin at the US National Library of Medicine Medical Subject Headings (MeSH)