TY  - GEN
A1  - Dunsing, Valentin
A1  - Magnus, Mayer
A1  - Liebsch, Filip
A1  - Multhaup, Gerhard
A1  - Chiantia, Salvatore
T1  - Direct Evidence of APLP1 Trans Interactions in Cell-Cell Adhesion Platforms Investigated via Fluorescence Fluctuation Spectroscopy
T2  - Biophysical journal
N2  - The Amyloid-precursor-like protein 1 (APLP1) is a neuronal type I transmembrane protein which plays a role in synaptic adhesion and synaptogenesis. Past investigations indicated that APLP1 is involved in the formation of protein-protein complexes that bridge the junctions between neighboring cells. Nevertheless, APLP1-APLP1 trans interactions have never been directly observed in higher eukaryotic cells. Here, we investigate APLP1 interactions and dynamics directly in living human embryonic kidney (HEK) cells, using fluorescence fluctuation spectroscopy techniques, namely cross-correlation scanning fluorescence correlation spectroscopy (sFCS) and Number&Brightness (N&B). Our results show that APLP1 forms homotypic trans complexes at cell-cell contacts. In the presence of zinc ions, the protein forms macroscopic clusters, exhibiting an even higher degree of trans binding and strongly reduced dynamics. Further evidence from Giant Plasma Membrane Vesicles and live cell actin staining suggests that the presence of an intact cortical cytoskeleton is required for zinc-induced cis multimerization. Subsequently, large adhesion platforms bridging interacting cells are formed through APLP1-APLP1 direct trans interactions. Taken together, our results provide direct evidence that APLP1 functions as a neuronal zinc-dependent adhesion protein and provide a more detailed understanding of the molecular mechanisms driving the formation of APLP1 adhesion platforms. Further, they show that fluorescence fluctuation spectroscopy techniques are useful tools for the investigation of protein-protein interactions at cell-cell adhesion sites.
Y1  - 2018
U6  - https://doi.org/10.1016/j.bpj.2017.11.2067
SN  - 0006-3495
SN  - 1542-0086
VL  - 114
IS  - 3
SP  - 373A
EP  - 373A
PB  - Cell Press
CY  - Cambridge
ER  -