A mass spectrometry-based proteomic analysis of Homer2-interacting proteins in the mouse brain

Publication date: Available online 17 July 2017
Source:Journal of Proteomics
Author(s): Scott P. Goulding, Karen K. Szumlinski, Candice Contet, Michael J. MacCoss, Christine C. Wu
In the brain, the Homer protein family modulates excitatory signal transduction and receptor plasticity through interactions with other proteins in dendritic spines. Homer proteins are implicated in a variety of psychiatric disorders such as schizophrenia and addiction. Since Homers serve as scaffolding proteins, identifying their interaction partners is an important first step in understanding their biological function and could help design novel therapeutic strategies. The present study set out to document Homer2-interacting proteins in the mouse brain using a co-immunoprecipitation-based mass spectrometry approach. Homer2 knockout samples were used to filter out non-specific interactors. We found that in the brain, Homer2 interacts with a limited subset of its previously reported interaction partners (3 out of 31). Importantly, we detected an additional 15 "novel" Homer2-interacting proteins, most of which are part of the N-methyl-d-aspartate receptor signaling pathway. These results corroborate the central role Homer2 plays in glutamatergic transmission and expand the network of proteins potentially contributing to the behavioral abnormalities associated with altered Homer2 expression.SignificanceHomer proteins are scaffolding proteins that regulate signal transduction in neurons. Identifying their interaction partners is key to understanding their function. We used co-immunoprecipitation in combination with mass spectrometry to establish the first comprehensive list of Homer2-interacting partners in the mouse brain. The specificity of interactions was evaluated using Homer2 knockout brain tissue as a negative control. The set of proteins that we identified minimally overlaps with previously reported interacting partners of Homer2. In particular, we identified novel interactors that are part of the signaling cascade activated by glutamatergic transmission, which improves our mechanistic understanding of the role of Homer2 in behavior.

Graphical abstract

http://ift.tt/2uF0vqV