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Wu, Yumei Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
Matsui, Hideki Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Kaken ID publons researchmap
Tomizawa, Kazuhito Department of Molecular Physiology, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University
Amphiphysin I, known as a major dynamin-binding partner localized on the collars of nascent vesicles, plays a key role in clathrin-mediated endocytosis (CME) of synaptic vesicles. Amphiphysin I mediates the invagination and fission steps of synaptic vesicles by sensing or facilitating membrane curvature and stimulating the GTPase activity of dynamin. Amphiphysin I may form a homodimer by itself or a heterodimer with amphiphysin II in vivo. Both amphiphysin I and II function as multilinker proteins in the clathrin-coated complex. Under normal physiological conditions, the functions of amphiphysin I and some other endocytic proteins are known to be regulated by phosphorylation and dephosphorylation. During hyperexcited conditions, the most recent data showed that amphiphysin I is truncated by the ca2-dependent protease calpain. Overexpression of the truncated form of amphi-physin I inhibited transferrin uptake and synaptic vesicle endocytosis (SVE). This suggests that amphi-physin I may be an important regulator for SVE when massive amounts of Ca2 flow into presynaptic terminals, a phenomenon observed in neurodegenerative disorders such as ischemia/anoxia, epilepsy, stroke, trauma and Alzheimer's disease. This review describes current knowledge regarding the general properties and functions of amphiphysin I as well as the functional regulations such as phosphorylation and proteolysis in nerve terminals.
Acta Medica Okayama
Okayama University Medical School
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