Desensitization of the neurokinin-1 receptor (NK1-R) in neurons: effects of substance P on the distribution of NK1-R, Galphaq/11, G-protein receptor kinase-2/3, and beta-arrestin-1/2.
Observations in reconstituted systems and transfected cells indicate that G-protein receptor kinases (GRKs) and beta-arrestins mediate desensitization and endocytosis of G-protein-coupled receptors. Little is known about receptor regulation in neurons. Therefore, we examined the effects of the neurotransmitter substance P (SP) on desensitization of the neurokinin-1 receptor (NK1-R) and on the subcellular distribution of NK1-R, Galphaq/11, GRK-2 and -3, and beta-arrestin-1 and -2 in cultured myenteric neurons. NK1-R was coexpressed with immunoreactive Galphaq/11, GRK-2 and -3, and beta-arrestin-1 and -2 in a subpopulation of neurons. SP caused 1) rapid NK1-R-mediated increase in [Ca2+]i, which was transient and desensitized to repeated stimulation; 2) internalization of the NK1-R into early endosomes containing SP; and 3) rapid and transient redistribution of beta-arrestin-1 and -2 from the cytosol to the plasma membrane, followed by a striking redistribution of beta-arrestin-1 and -2 to endosomes containing the NK1-R and SP. In SP-treated neurons Galphaq/11 remained at the plasma membrane, and GRK-2 and -3 remained in centrally located and superficial vesicles. Thus, SP induces desensitization and endocytosis of the NK1-R in neurons that may be mediated by GRK-2 and -3 and beta-arrestin-1 and -2. This regulation will determine whether NK1-R-expressing neurons participate in functionally important reflexes.
Department of Surgery, University of California San Francisco, San Francisco, California 94143-0660, USA.
K
K
McConalogue
C U
CU
Corvera
P D
PD
Gamp
E F
EF
Grady
N W
NW
Bunnett
D000818:Animals; D000831:Animals, Newborn; D019390:Arrestins / Q000096:biosynthesis* / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000096:biosynthesis* / Q000235:genetics; D054770:G-Protein-Coupled Receptor Kinase 3; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D009197:Myenteric Plexus / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D018040:Receptors, Neurokinin-1 / Q000096:biosynthesis* / Q000235:genetics; D013373:Substance P / Q000494:pharmacology* / Q000502:physiology; D014162:Transfection; D051552:beta-Adrenergic Receptor Kinases; D000071557:beta-Arrestins
D019390:Arrestins; D018040:Receptors, Neurokinin-1; D000071557:beta-Arrestins; D013373:Substance P; D020794:Receptor Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D054770:G-Protein-Coupled Receptor Kinase 3; D051552:beta-Adrenergic Receptor Kinases; D002118:Calcium