Functional dissection of the interactions of stonin 2 with the adaptor complex AP-2 and synaptotagmin.
Synaptic vesicle recycling is in part mediated by clathrin-mediated endocytosis. This process involves the coordinated assembly of clathrin and adaptor proteins and the concomitant selection of cargo proteins. Here, we demonstrate that the endocytotic protein stonin 2 localizes to axonal vesicle clusters through its micro-homology domain. Interaction of this domain with synaptotagmin I is sufficient to recruit stonin 2 to the plasmalemma. The N-terminal domain of stonin 2 harbors multiple AP-2-interaction motifs that bind to the clathrin adaptor complex AP-2. These motifs with the consensus sequence WVxF are capable of binding to the alpha-adaptin ear domain and to micro2. Mutation of the tyrosine motif-binding pocket of micro2 abolishes recognition of the WVxF peptide, suggesting that association with stonin 2 renders AP-2 incompetent to sort tyrosine motif-containing cargo proteins. We hypothesize that stonin 2 may function as an AP-2-dependent sorting adaptor for synaptic vesicle recycling.
Walther
Kristin
K
Department of Biochemistry II, Zentrum für Biochemie and Molekulare Zellbiologie, University of Göttingen, Humboldtallee 23, 37073 Göttingen, Germany.
Diril
M Kasim
MK
Jung
Nadja
N
Haucke
Volker
V
D033962:Adaptor Protein Complex 2 / Q000378:metabolism*; D033965:Adaptor Protein Complex alpha Subunits / Q000378:metabolism; D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D004705:Endocytosis; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D011485:Protein Binding; D050863:Synaptotagmin I; D050857:Synaptotagmins; D014168:Transferrin / Q000378:metabolism; D033921:Vesicular Transport Proteins
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C429267:STON2 protein, human; C494310:SYT1 protein, human; D050863:Synaptotagmin I; D014168:Transferrin; D033921:Vesicular Transport Proteins; D050857:Synaptotagmins