SYT3 Human

Synaptotagmin III was first cloned from a rat brain cDNA library by Mizuta et al. in 1994 . The protein consists of 588 amino acids and shares significant identity with other synaptotagmins, such as synaptotagmin-1 and synaptotagmin-2 . The high degree of conservation in the regulatory domain of protein kinase C among these synaptotagmins suggests a crucial role in cellular signaling .

Synaptotagmin III mRNA is expressed in the brain, various endocrine tissues, and hormone-secreting clonal cells . It is involved in calcium-dependent exocytosis of secretory vesicles in both endocrine cells and neurons . In vitro studies have shown that recombinant rat SYT3 exhibits calcium-dependent binding to phospholipids and syntaxins, as well as calcium-independent binding to adaptor protein-2 .

Recent research has highlighted the role of SYT3 in synaptic plasticity. Awasthi et al. (2019) discovered that SYT3 localizes to postsynaptic endocytic zones and is involved in the removal of AMPA receptors from synaptic plasma membranes in response to stimulation . This process is essential for long-term depression (LTD) and the decay of long-term potentiation (LTP) of synaptic strength . Mice lacking SYT3 exhibited normal learning but showed a lack of forgetting, indicating the importance of SYT3 in memory processes .

The SYT3 gene is located on human chromosome 19q13.33 . In mice, the Syt3 gene is located on chromosome 7, and it is closely linked to the kallikrein gene family . This conserved linkage group includes at least 28 genes, highlighting the evolutionary importance of this region .