Stonin 2 is a major adaptor protein for clathrin-mediated synaptic vesicle retrieval.
At small synapses in the brain, clathrin-mediated endocytosis (CME) is the dominant mode of synaptic vesicle retrieval following weak stimulation [1-4]. Clathrin cannot bind to membranes or cargo directly and instead uses adaptor proteins to do so [5]. Although the involvement of clathrin and dynamin in synaptic vesicle retrieval is clear, it is unknown which adaptor proteins are used to sort the essential components into the vesicle [1, 4, 6]. In nonneuronal cells, CME of the majority of transmembrane receptors is either directly or indirectly via the heterotetrameric AP-2 complex [5]. In neurons, RNAi of the μ2 subunit of AP-2 resulted in only minor inhibition of synaptic vesicle retrieval [7, 8], a result echoed in C. elegans [9]. These results suggest that alternative adaptors may be employed for vesicle retrieval. Here, we tested which adaptors are required for vesicle retrieval at hippocampal synapses using a targeted RNAi screen coupled with optical measurements. Stonin 2 emerged as a major adaptor, whereas AP-2 played only a minor role in endocytosis at the synapse. Moreover, using chemically induced rerouting of stonin 2 to mitochondria it was possible to switch endocytically competent synapses to an impaired state on a timescale of minutes.
Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown Street, Liverpool, L69 3BX, UK.
Anna K
AK
Willox
Stephen J
SJ
Royle
D033962:Adaptor Protein Complex 2 / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D022163:Clathrin-Coated Vesicles / Q000502:physiology*; D004705:Endocytosis / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008928:Mitochondria / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D013572:Synaptic Vesicles / Q000502:physiology*
D033962:Adaptor Protein Complex 2; D033942:Adaptor Proteins, Vesicular Transport; C576989:Ston2 protein, rat