Synaptotagmin/A0039

Synaptotagmin, also known as A0039, is an intrinsic membrane protein of synaptic vesicles.

Synaptotagmin, also known as A0039, is an intrinsic membrane protein of synaptic vesicles. It binds syntaxin (located at the plasma membrane) in a calcium-dependent manner and is believed to act as the calcium sensor for fast exocytotic neurotransmitter release, such as that found at central synapses. A0039 binds three calcium ions per subunit. Other synaptotagmin family members mediate slower vesicle release. Knock-out mice die within 2 days of birth. Neurons cultured from null mice show severely impaired synaptic transmission. Spontaneous vesicle release, which is calcium-independent, is not affected. The protein is 421 amino acids long, with a molecular weight of 47.4 kDa. The gene is located on mouse chromosome 10.