Synaptophysin
Protein-coding gene in the species Homo sapiens
From Wikipedia, the free encyclopedia
Synaptophysin, also known as the major synaptic vesicle protein p38, is a protein that in humans is encoded by the SYP gene.[5][6]
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.[citation needed]
Tissue distribution
It is expressed in neuroendocrine cells and in virtually all neurons in the brain and spinal cord that participate in synaptic transmission.[citation needed]
Structure
The protein is a synaptic vesicle glycoprotein with four transmembrane domains weighing 38 kDa.[citation needed]
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
See also
- List of human genes
- Merkel-cell carcinoma - although origin of this tumor is unclear, it does express synaptophysin