Distribution of RGS9-2 in neurons of the mouse striatum.
Regulators of G protein signaling (RGS) proteins negatively modulate G protein-coupled receptor (GPCR) signaling activity by accelerating G protein hydrolysis of GTP, hastening pathway shutoff. A wealth of data from cell culture experiments using exogenously expressed proteins indicates that RGS9 and other RGS proteins have the potential to down-regulate a significant number of pathways. We have used an array of biochemical and tissue staining techniques to examine the subcellular localization and membrane binding characteristics of endogenous RGS9-2 and known binding partners in rodent striatum and tissue homogenates. A small fraction of RGS9-2 is present in the soluble cytoplasmic fraction, whereas the majority is present primarily associated with the plasma membrane and structures insoluble in non-ionic detergents that efficiently extract the vast majority of its binding partners, R7BP and G(beta5). It is specifically excluded from the cell nucleus in mouse striatal tissue. In cultured striatal neurons, RGS9-2 is found at extrasynaptic sites primarily along the dendritic shaft near the spine neck. Heterogeneity in RGS9-2 detergent solubility along with its unique subcellular localization suggests that its mechanism of membrane anchoring and localization is complex and likely involves additional proteins beside R7BP. An important nuclear function for RGS9-2 seems unlikely.
Mancuso
James J
JJ
Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
Qian
Yan
Y
Long
Cheng
C
Wu
Gang-Yi
GY
Wensel
Theodore G
TG
D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D018920:Coculture Techniques / Q000379:methods; D003342:Corpus Striatum / Q000166:cytology / Q000378:metabolism*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000648:ultrastructure; D011485:Protein Binding; D020710:RGS Proteins / Q000172:deficiency / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013347:Subcellular Fractions / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D035362:Transcription Factor TFIID / Q000378:metabolism; D000099273:Neurabins
D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D044387:GTP-Binding Protein beta Subunits; D005968:Glutamate Decarboxylase; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D020710:RGS Proteins; D035362:Transcription Factor TFIID; D000099273:Neurabins; C497929:Ppp1r1b protein, mouse; C499440:R7BP protein, mouse; C116925:regulator of g-protein signaling 9; C401141:glutamate decarboxylase 2