Related Experiment Video
Updated: Aug 21, 2026

Dissecting Multi-protein Signaling Complexes by Bimolecular Complementation Affinity Purification (BiCAP)
Published on: June 15, 2018
Recognition of a basic AP-2 binding motif within the C2B domain of synaptotagmin is dependent on multimerization
Isabelle Grass1, Stefanie Thiel, Stefan Höning
1Institut für Chemie-Biochemie, Freie Universität Berlin, Takustrasse 6, D-14195 Berlin, Germany.
Abstract:
Synaptotagmin is a multifunctional membrane protein that may regulate exo-endocytic cycling of synaptic vesicles at the presynaptic plasmalemma. Its C2B domain has been postulated to interact with a variety of effector molecules including acidic phospholipids, phosphoinositides, SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), calcium channels, and the clathrin adaptor complex AP-2. Here we report that a basic motif within the C2B domain is required and sufficient for binding to AP-2 via its mu2 subunit and that this interaction is dependent on multimerization of the AP-2 binding site. Moreover, we show that upon fusion to a plasma membrane reporter protein this sequence is sufficient to target the chimeric molecule for internalization. We hypothesize that basic motifs within multimeric membrane proteins may represent a novel type of clathrin/AP-2-dependent endocytosis signal.
Related Concept Videos
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Catenins
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
Ligand Binding and Linkage
Cooperative Allosteric Transitions
Structure of Cadherins

