ANKRD13C acts as a molecular chaperone for G protein-coupled receptors.
Although the mechanisms that regulate folding and maturation of newly synthesized G protein-coupled receptors are crucial for their function, they remain poorly characterized. By yeast two-hybrid screening, we have isolated ANKRD13C, a protein of unknown function, as an interacting partner for the DP receptor for prostaglandin D(2). In the present study we report the characterization of this novel protein as a regulator of DP biogenesis and trafficking in the biosynthetic pathway. Co-localization by confocal microscopy with an endoplasmic reticulum (ER) marker, subcellular fractionation experiments, and demonstration of the interaction between ANKRD13C and the cytoplasmic C terminus of DP suggest that ANKRD13C is a protein associated with the cytosolic side of ER membranes. Co-expression of ANKRD13C with DP initially increased receptor protein levels, whereas siRNA-mediated knockdown of endogenous ANKRD13C decreased them. Pulse-chase experiments indicated that ANKRD13C can promote the biogenesis of DP by inhibiting the degradation of newly synthesized receptors. However, a prolonged interaction between ANKRD13C and DP resulted in ER retention of misfolded/unassembled forms of the receptor and to their proteasome-mediated degradation. ANKRD13C also regulated the expression of other GPCRs tested (CRTH2, thromboxane A(2) (TPα), and β2-adrenergic receptor), whereas it did not affect the expression of green fluorescent protein, GRK2 (G protein-coupled receptor kinase 2), and VSVG (vesicular stomatitis virus glycoprotein), showing specificity toward G protein-coupled receptors. Altogether, these results suggest that ANKRD13C acts as a molecular chaperone for G protein-coupled receptors, regulating their biogenesis and exit from the ER.
Parent
Audrey
A
Service de Rhumatologie, Département de Médecine, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Centre de Recherche Clinique Etienne-Lebel and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada.
Roy
Sébastien J
SJ
Iorio-Morin
Christian
C
Lépine
Marie-Claude
MC
Labrecque
Pascale
P
Gallant
Maxime A
MA
Slipetz
Deborah
D
Parent
Jean-Luc
JL
D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis* / Q000235:genetics
C555243:ANKRD13C protein, human; D008565:Membrane Proteins; D018832:Molecular Chaperones; D034741:RNA, Small Interfering; D043562:Receptors, G-Protein-Coupled