Sorting Nexin 9 Interacts with Dynamin 1 and N-WASP and Coordinates Synaptic Vesicle Endocytosis

• Published in: The Journal of biological chemistry 2007-09, Vol.282 (39), p.28939-28950
• Main Authors: Shin, Narae, Lee, Suho, Ahn, Namhui, Kim, Soo-A, Ahn, Sang-Gun, YongPark, Zee, Chang, Sunghoe
• Format: Article
• Language: English
• Subjects: Animals; Carrier Proteins - antagonists & inhibitors; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cells, Cultured; Chlorocebus aethiops; Clathrin - genetics; Clathrin - metabolism; COS Cells; Dimerization; Dynamin I - genetics; Dynamin I - metabolism; Endocytosis - drug effects; Endocytosis - physiology; Hippocampus - cytology; Hippocampus - metabolism; Neurons - cytology; Neurons - metabolism; Protein Structure, Tertiary - physiology; Rats; Rats, Sprague-Dawley; RNA, Small Interfering - pharmacology; Sorting Nexins; Synaptic Vesicles - genetics; Synaptic Vesicles - metabolism; Vesicular Transport Proteins - antagonists & inhibitors; Vesicular Transport Proteins - genetics; Vesicular Transport Proteins - metabolism; Wiskott-Aldrich Syndrome Protein, Neuronal - genetics; Wiskott-Aldrich Syndrome Protein, Neuronal - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M700283200

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.