Differential expression and interaction with the visual G-protein transducin of centrin isoforms in mammalian photoreceptor cells.
Photoisomerization of rhodopsin activates a heterotrimeric G-protein cascade leading to closure of cGMP-gated channels and hyperpolarization of photoreceptor cells. Massive translocation of the visual G-protein transducin, Gt, between subcellular compartments contributes to long term adaptation of photoreceptor cells. Ca(2+)-triggered assembly of a centrin-transducin complex in the connecting cilium of photoreceptor cells may regulate these transducin translocations. Here we demonstrate expression of all four known, closely related centrin isoforms in the mammalian retina. Interaction assays revealed binding potential of the four centrin isoforms to Gtbetagamma heterodimers. High affinity binding to Gtbetagamma and subcellular localization of the centrin isoforms Cen1 and Cen2 in the connecting cilium indicated that these isoforms contribute to the centrin-transducin complex and potentially participate in the regulation of transducin translocation through the photoreceptor cilium. Binding of Cen2 and Cen4 to Gbetagamma of non-visual G-proteins may additionally regulate G-proteins involved in centrosome and basal body functions.
Giessl
Andreas
A
Institut für Zoologie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
Pulvermüller
Alexander
A
Trojan
Philipp
P
Park
Jung Hee
JH
Choe
Hui-Woog
HW
Ernst
Oliver Peter
OP
Hofmann
Klaus Peter
KP
Wolfrum
Uwe
U
D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D002417:Cattle; D018385:Centrosome / Q000378:metabolism; D002845:Chromatography; D002923:Cilia / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005982:Glutathione Transferase / Q000378:metabolism; D007700:Kinetics; D008027:Light; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D011485:Protein Binding; D020033:Protein Isoforms; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000737:chemistry; D012160:Retina / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012243:Rhodopsin / Q000737:chemistry; D012374:Rod Cell Outer Segment / Q000737:chemistry; D012542:Scattering, Radiation; D017422:Sequence Analysis, DNA; D015293:Transducin / Q000096:biosynthesis / Q000737:chemistry*
C107745:CETN3 protein, human; C481087:CETN4 protein, mouse; D002135:Calcium-Binding Proteins; C424436:Cetn2 protein, mouse; C486352:Cetn3 protein, mouse; D020033:Protein Isoforms; D011994:Recombinant Proteins; D012243:Rhodopsin; D005982:Glutathione Transferase; D015293:Transducin; D006152:Cyclic GMP; D002118:Calcium