Uncovering the BIN1-SH3 interactome underpinning centronuclear myopathy

Abstract

Deletion of the protein-protein interaction SH3 domain of the membrane remodeling BIN1 protein was found to lead to centronuclear myopathy in patients, yet only few interaction partners of BIN1 SH3 have been identified so far. Here we used the holdup assay to proteome-wide measure steady-state affinity constants of BIN1 SH3 domain for thousands of full-length cellular proteins, as well as for hundreds of putative SH3-binding sites found within the identified BIN1 binders. Besides confirming known partners, such as DNM2, we also identified and affinity-characterized numerous others. We also assessed the impact of a set of rare natural BIN1 SH3 domain variants on affinity interactomes and identified a set of potentially harmful ones that exhibited perturbed affinity profiles, whose impacts were confirmed by cellular assay, tentatively connecting them to neuromuscular disorders.

Dynamics of membrane tubulation coupled with fission by a two-component module revealed on polymer cushioned bilayer islands

“…3F). The binding affinity of the BIN1 SH3 domain for the Dyn2 PRD is ~70 μM 35 and recent analysis reports an affinity of the BIN1 SH3 domain for Dyn2 to be ~10 μM 11 , which is still rather low. But Dyn2 was present on BIN1 tubules under conditions that showed no fission (Fig.…”

“…The muscle-specific isoform (isoform 8) of amphiphysin 2, also called BIN1, and the ubiquitous isoform of dynamin2 (Dyn2) are critical structural components of T-tubules 10 . BIN1 contains the N-terminal N-BAR domain that bends membranes and the C-terminal Src homology 3 (SH3) domain that interacts with the proline-rich domain (PRD) in dynamins 11,12 . The clathrin and adaptor protein 2 (AP2) binding motifs are absent in BIN1.…”