Sorting nexin 9 interacts with dynamin 1 and N-WASP and coordinates synaptic vesicle endocytosis.
Sorting nexin 9 (SNX9) is a member of the sorting nexin family of proteins, each of which contains a characteristic Phox homology domain. SNX9 is widely expressed and plays a role in clathrin-mediated endocytosis, but it is not known if it is present in neuronal cells. We report that SNX9 is expressed in the presynaptic compartment of cultured hippocampal neurons, where it binds to dynamin-1 and N-WASP. Overexpression of full-length SNX9 or a C-terminal truncated version caused severe defects in synaptic vesicle endocytosis during, as well as after, stimulation. Knockdown of SNX9 with short interfering RNA also reduced synaptic vesicle endocytosis, and the W39A mutation of SNX9 abolished the inhibitory effect of SNX9 on endocytosis. Rescue experiments showed that most of the effect of SNX9 on endocytosis results from its interaction with dynamin 1, although its interaction with N-WASP contributes in some degree. We further showed that SNX9 dimerizes through its C-terminal domain, suggesting that it may interact simultaneously with dynamin 1 and N-WASP. We propose that SNX9 interacts with dynamin-1 and N-WASP in presynaptic terminals, where it links actin dynamics and synaptic vesicle endocytosis.
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712.
Narae
N
Shin
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712.
Suho
S
Lee
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712.
Namhui
N
Ahn
Department of Biochemistry, Dongguk University, College of Oriental Medicine, Gyeongju 780-714.
Soo-A
SA
Kim
Department of Pathology, Chosun University, College of Dentistry, Gwangju 501-759, South Korea.
Sang-Gun
SG
Ahn
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712.
Zee
Z
YongPark
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712. Electronic address: sunghoe@gist.ac.kr.
Sunghoe
S
Chang
D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D002966:Clathrin / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D034284:Dynamin I / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D058305:Sorting Nexins; D013572:Synaptic Vesicles / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D002966:Clathrin; D034741:RNA, Small Interfering; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins; C495770:Wasl protein, rat; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; D034284:Dynamin I