Sinapsins

Sinapsins are a family of proteins that play a crucial role in the regulation of neurotransmitter release at the presynaptic terminal of neurons. They are involved in the clustering and recycling of synaptic vesicles, which are small membrane-bound structures that contain neurotransmitters. Sinapsins are typically found in the cytoplasm of neurons and are thought to interact with other proteins, such as synaptotagmin and Munc18, to form a complex that facilitates the fusion of synaptic vesicles with the presynaptic membrane.

There are four known sinapsin isoforms, each with distinct functions and expression patterns. Sinapsin I is primarily expressed in the central nervous system and is involved in the regulation of neurotransmitter release in both excitatory and inhibitory synapses. Sinapsin II is also expressed in the central nervous system and is involved in the regulation of neurotransmitter release in excitatory synapses. Sinapsin III is expressed in both the central and peripheral nervous systems and is involved in the regulation of neurotransmitter release in both excitatory and inhibitory synapses. Sinapsin IV is expressed in the peripheral nervous system and is involved in the regulation of neurotransmitter release in both excitatory and inhibitory synapses.

Mutations in the sinapsin genes have been linked to several neurological disorders, including autism spectrum disorder, schizophrenia, and intellectual disability. Additionally, sinapsins have been implicated in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. The exact mechanisms by which sinapsins contribute to these disorders are not yet fully understood, but it is thought that they may play a role in the dysregulation of neurotransmitter release and synaptic plasticity.