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Chimeric Gα q mutants harboring the last five carboxy‐terminal residues of Gα i2 or Gα o are resistant to pertussis toxin‐catalyzed ADP‐ribosylation
Author(s) -
Joshi Sushma A.,
Fan Kenneth P.K.,
Ho Vanessa W.S.,
Wong Yung H.
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01527-0
Subject(s) - pertussis toxin , g protein , adp ribosylation , chimera (genetics) , receptor , gq alpha subunit , microbiology and biotechnology , stimulation , gs alpha subunit , biology , cyclase , chemistry , biochemistry , endocrinology , enzyme , gene , nad+ kinase
Three widely‐used Gα q chimeras harboring the last five residues of Gα i , Gα o and Gα z (qi5, qo5 and qz5) were examined for their ability to serve as substrates for pertussis toxin (PTX)‐catalyzed ADP‐ribosylation. In COS‐7 cells coexpressing one of the three opioid receptors (μ, δ, and κ) and a Gα q chimera, agonist‐induced stimulation of phosphoinositide‐specific phospholipase C (PI‐PLC) was largely insensitive to PTX treatment. Only the qi5‐mediated stimulation of PI‐PLC by κ‐opioids was partially inhibited by PTX. In βγ‐release assays, PTX treatment did not affect the ability of opioid receptors to activate these chimeras. [ 32 P]ADP‐ribosylation labeled Gα i/o but not qi5 or qo5, although the expression of these chimeras was confirmed by immunodetection. Thus, Gα q chimeras with a Gα i/o ‐like tail are insensitive to PTX treatment.