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Chronic and Intermittent Ethanol Treatment Differentially Regulates Membrane Compartmentalization of G‐protein Subunits in Rat Brain
Author(s) -
Miller James,
Wiley Aidan,
Luessen Deborah,
McCool Brian,
Chen Rong
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2019.33.1_supplement.809.2
Subject(s) - lipid raft , chemistry , compartmentalization (fire protection) , g protein , microbiology and biotechnology , g protein coupled receptor , membrane protein , protein subunit , receptor , ethanol , membrane , biochemistry , biology , enzyme , gene
Ethanol exposure produces profound changes in the trafficking and activity of many G‐protein coupled receptors (GPCRs) which are associated with alcohol preference, tolerance, and dependence. However, the molecular mechanism involved in ethanol‐induced changes in receptor function remains unclear. Our lab previously found that ethanol treatment increases cholesterol content in rat brain, altering membrane lipid composition. Cholesterol, enriched in lipid rafts of membranes, plays an important role in membrane integrity and promotes the recruitment of signaling molecules. Ethanol‐induced disruption of brain cholesterol homeostasis would influence the signaling of many membrane‐bound GPCRs and channels. This study aimed to examine whether CIE also causes changes in the membrane localization of G‐protein subunits which are tightly associated with many GPCRs and channels. Methods Male Sprague Dawley rats were exposed to 7 cycles of 12 hours of ethanol vapor inhalation followed by 12 hours of normal air. Rats were sacrificed 24 hours after the final ethanol exposure and the prefrontal cortex (PFC) tissue was dissected. Samples were homogenized followed by discontinuous sucrose density (5%–40%) ultracentrifugation and separated by density into 15 fractions. Western blotting was performed to determine the localization of G‐protein subunits on in lipid raft and non‐lipid raft fractions. Results CIE selectively altered membrane compartmentalization of certain subunits of G‐protein. There was an increase in localization of Gαo subunit from lipid rafts to non‐lipid rafts in CIE‐treated rat PFC. In contrast, CIE caused Gβ subunit to translocate from non‐lipid rafts to lipid rafts. Moreover, CIE had no effect on membrane compartmentalization of Gαi3 and Gαq. These results indicate selective changes in location of certain G‐protein subunits, altering proximal microdomain interaction with membrane channels and receptors and thus downstream signaling. This provides a possible mechanism underlying cholesterol‐mediated changes in GPCR signaling in rat brain tissue. Support or Funding Information This project is supported by NIH R01DA042862, P50DA006634, F31AA025532. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .