Dual interaction of synaptotagmin with mu2- and alpha-adaptin facilitates clathrin-coated pit nucleation.
The synaptic vesicle protein synaptotagmin was proposed to act as a major docking site for the recruitment of clathrin coats implicated in endocytosis, including the recycling of synaptic vesicles. We show here that the C2B domain of synaptotagmin binds mu2- and alpha-adaptin, two of the four subunits of the endocytic adaptor complex AP-2. mu2 represents the major interacting subunit of AP-2 within this complex. Its binding to synaptotagmin is mediated by a site in subdomain B that is distinct from the binding site for tyrosine-based sorting motifs located in subdomain A. The presence of the C2B domain of synaptotagmin at the surface of liposomes enhances the recruitment of AP-2 and clathrin. Conversely, perturbation of the interaction between synaptotagmin and AP-2 by synprint, the cytoplasmic synaptotagmin-binding domain of N-type calcium channels, inhibits transferrin internalization in living cells. We conclude that a dual interaction of synaptotagmin with the clathrin adaptor AP-2 plays a key physiological role in the nucleation of endocytic clathrin-coated pits.
Haucke
V
V
Department of Cell Biology and Howard Hughes Medical Institute, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06510, USA.
Wenk
M R
MR
Chapman
E R
ER
Farsad
K
K
De Camilli
P
P
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033963:Adaptor Protein Complex 3; D033965:Adaptor Protein Complex alpha Subunits; D033983:Adaptor Protein Complex mu Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D002135:Calcium-Binding Proteins; D002966:Clathrin / Q000737:chemistry / Q000378:metabolism*; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism*; D006224:Cricetinae; D066298:In Vitro Techniques; D008081:Liposomes; D008239:Lysine / Q000737:chemistry; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D051381:Rats; D013572:Synaptic Vesicles / Q000378:metabolism; D050857:Synaptotagmins; D014443:Tyrosine / Q000737:chemistry
D033961:Adaptor Protein Complex 1; D033962:Adaptor Protein Complex 2; D033963:Adaptor Protein Complex 3; D033965:Adaptor Protein Complex alpha Subunits; D033983:Adaptor Protein Complex mu Subunits; D033942:Adaptor Proteins, Vesicular Transport; C510072:Ap3m2 protein, rat; D002135:Calcium-Binding Proteins; D002966:Clathrin; D008081:Liposomes; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D021122:Protein Subunits; C499065:adaptor protein complex 1, mu 2 subunit; C438886:adaptor protein complex 2, mu 2 subunit; D050857:Synaptotagmins; D014443:Tyrosine; D008239:Lysine