%0 Journal Article
%T Amphiphysin I and regulation of synaptic vesicle endocytosis
%A Wu
%A Yumei
%A Matsui
%A Hideki
%A Tomizawa
%A Kazuhito
%J Acta Medica Okayama
%D 2009
%I Okayama University Medical School
%X 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.
%K amphiphysin I
%K calpain
%K SVE
%K hyperexcitation
%K seizure
%U http://ousar.lib.okayama-u.ac.jp/file/31822/fulltext.pdf