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Updated: May 20, 2026

Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
Transient GPI-anchored protein homodimers are units for raft organization and function
Kenichi G N Suzuki1, Rinshi S Kasai, Koichiro M Hirosawa
1Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto, Japan.
Abstract:
Advanced single-molecule fluorescent imaging was applied to study the dynamic organization of raft-associated glycosylphosphatidylinositol-anchored proteins (GPI-APs) in the plasma membrane and their stimulation-induced changes. In resting cells, virtually all of the GPI-APs are mobile and continually form transient (~200 ms) homodimers (termed homodimer rafts) through ectodomain protein interactions, stabilized by the presence of the GPI-anchoring chain and cholesterol. Heterodimers do not form, suggesting a fundamental role for the specific ectodomain protein interaction. Under higher physiological expression conditions , homodimers coalesce to form hetero- and homo-GPI-AP oligomer rafts through raft-based lipid interactions. When CD59 was ligated, it formed stable oligomer rafts containing up to four CD59 molecules, which triggered intracellular Ca(2+) responses that were dependent on GPI anchorage and cholesterol, suggesting a key part played by transient homodimer rafts. Transient homodimer rafts are most likely one of the basic units for the organization and function of raft domains containing GPI-APs.
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