Transmembrane Complexes of DAP12 Crystallized in Lipid Membranes Provide Insights into Control of Oligomerization in Immunoreceptor Assembly

Konstantin Knoblich, Soohyung Park, Mariam Lutfi, Leonie van't Hag, Charlotte E. Conn, Shane A. Seabrook, Janet Newman, Peter E. Czabotar, Wonpil Im, Matthew E. Call, Melissa J. Call

Research output: Contribution to journalArticleResearchpeer-review

18 Citations (Scopus)

Abstract

The membrane-spanning α helices of single-pass receptors play crucial roles in stabilizing oligomeric structures and transducing biochemical signals across the membrane. Probing intermolecular transmembrane interactions in single-pass receptors presents unique challenges, reflected in a gross underrepresentation of their membrane-embedded domains in structural databases. Here, we present two high-resolution structures of transmembrane assemblies from a eukaryotic single-pass protein crystallized in a lipidic membrane environment. Trimeric and tetrameric structures of the immunoreceptor signaling module DAP12, determined to 1.77-Å and 2.14-Å resolution, respectively, are organized by the same polar surfaces that govern intramembrane assembly with client receptors. We demonstrate that, in addition to the well-studied dimeric form, these trimeric and tetrameric structures are made in cells, and their formation is competitive with receptor association in the ER. The polar transmembrane sequences therefore act as primary determinants of oligomerization specificity through interplay between charge shielding and sequestration of polar surfaces within helix interfaces.

Original languageEnglish
Pages (from-to)1184-1192
Number of pages9
JournalCell Reports
Volume11
Issue number8
DOIs
Publication statusPublished - 26 May 2015
Externally publishedYes

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