First Author | Tracy CM | Year | 2015 |
Journal | PLoS One | Volume | 10 |
Issue | 2 | Pages | e0117129 |
PubMed ID | 25659125 | Mgi Jnum | J:226862 |
Mgi Id | MGI:5698769 | Doi | 10.1371/journal.pone.0117129 |
Citation | Tracy CM, et al. (2015) Retinal cone photoreceptors require phosducin-like protein 1 for G protein complex assembly and signaling. PLoS One 10(2):e0117129 |
abstractText | G protein beta subunits (Gbeta) play essential roles in phototransduction as part of G protein betagamma (Gbetagamma) and regulator of G protein signaling 9 (RGS9)-Gbeta5 heterodimers. Both are obligate dimers that rely on the cytosolic chaperone CCT and its co-chaperone PhLP1 to form complexes from their nascent polypeptides. The importance of PhLP1 in the assembly process was recently demonstrated in vivo in a retinal rod-specific deletion of the Phlp1 gene. To test whether this is a general mechanism that also applies to other cell types, we disrupted the Phlp1 gene specifically in mouse cones and measured the effects on G protein expression and cone visual signal transduction. In PhLP1-deficient cones, expression of cone transducin (Gt2) and RGS9-Gbeta5 subunits was dramatically reduced, resulting in a 27-fold decrease in sensitivity and a 38-fold delay in cone photoresponse recovery. These results demonstrate the essential role of PhLP1 in cone G protein complex formation. Our findings reveal a common mechanism of Gbetagamma and RGS9-Gbeta5 assembly in rods and cones, highlighting the importance of PhLP1 and CCT-mediated Gbeta complex formation in G protein signaling. |