A General Model for Preferential Hetero-oligomerization of LIN-2/7 Domains: Mechanism Underlying Directed Assembly of Supramolecular Signaling ComplexesPetrosky, K.Y., Ou, H.D., Lohr, F., Dotsch, V., Lim, W.A.
(2005) J Biol Chem 280: 38528-38536
- PubMed: 16147993
- DOI: https://doi.org/10.1074/jbc.M506536200
- Primary Citation of Related Structures:
- PubMed Abstract:
LIN-2/7 (L27) domains are protein interaction modules that preferentially hetero-oligomerize, a property critical for their function in directing specific assembly of supramolecular signaling complexes at synapses and other polarized cell-cell junctions. We have solved the solution structure of the heterodimer composed of the L27 domains from LIN-2 and LIN-7. Comparison of this structure with other L27 domain structures has allowed us to formulate a general model for why most L27 domains form an obligate heterodimer complex. L27 domains can be divided in two types (A and B), with each heterodimer comprising an A/B pair. We have identified two keystone positions that play a central role in discrimination. The residues at these positions are energetically acceptable in the context of an A/B heterodimer, but would lead to packing defects or electrostatic repulsion in the context of A/A and B/B homodimers. As predicted by the model, mutations of keystone residues stabilize normally strongly disfavored homodimers. Thus, L27 domains are specifically optimized to avoid homodimeric interactions.
Biophysics Graduate Program, University of California, San Francisco, California 94143, USA.