Dominant negative effects of human follicle-stimulating hormone receptor expression-deficient mutants on wild-type receptor cell surface expression. Rescue of oligomerization-dependent defective receptor expression by using cognate decoys.
Current evidence indicates that G protein-coupled receptors form dimers that may affect biogenesis and membrane targeting of the complexed receptors. We here analyzed whether expression-deficient follicle-stimulating hormone receptor (FSHR) mutants exert dominant negative actions on wild-type FSHR cell surface membrane expression. Co-transfection of constant amounts of wild-type receptor cDNA and increasing quantities of mutant (R556A or R618A) FSHR cDNAs progressively decreased agonist-stimulated cAMP accumulation, [(125)I]-FSH binding, and plasma membrane expression of the mature wild-type FSHR species. Co-transfection of wild-type FSHR fragments involving transmembrane domains 5-6, or transmembrane domain 7 and/or the carboxyl-terminus specifically rescued wild-type FSHR expression from the transdominant inhibition by the mutants. Mutant FSHRs also inhibited function of the luteinizing hormone receptor but not that of the thyrotropin receptor or non-related receptors. Defective intracellular transport and/or interference with proper maturation due to formation of misfolded mutant:wild-type receptor complexes may explain the negative effects provoked by the altered FSHRs.
Zariñán
Teresa
T
Research Unit in Reproductive Medicine, Hospital de Ginecobstetricia Luis Castelazo Ayala, Instituto Mexicano del Seguro Social, Mexico, DF, Mexico.
Perez-Solís
Marco A
MA
Maya-Núñez
Guadalupe
G
Casas-González
Patricia
P
Conn
P Michael
PM
Dias
James A
JA
Ulloa-Aguirre
Alfredo
A
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002460:Cell Line; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D017510:Protein Folding; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011962:Receptors, FSH / Q000235:genetics* / Q000378:metabolism*
D011956:Receptors, Cell Surface; D011962:Receptors, FSH