Interaction of serotonin 5-hydroxytryptamine type 2C receptors with PDZ10 of the multi-PDZ domain protein MUPP1.
By using the yeast two-hybrid system, we previously isolated a cDNA clone encoding a novel member of the multivalent PDZ protein family called MUPP1 containing 13 PDZ domains. Here we report that the C terminus of the 5-hydroxytryptamine type 2C (5-HT(2C)) receptor selectively interacts with the 10th PDZ domain of MUPP1. Mutations in the extreme C-terminal SSV sequence of the 5-HT(2C) receptor confirmed that the SXV motif is critical for the interaction. Co-immunoprecipitations of MUPP1 and 5-HT(2C) receptors from transfected COS-7 cells and from rat choroid plexus verified this interaction in vivo. Immunocytochemistry revealed an SXV motif-dependent co-clustering of both proteins in transfected COS-7 cells as well as a colocalization in rat choroid plexus. A 5-HT(2C) receptor-dependent unmasking of a C-terminal vesicular stomatitis virus epitope of MUPP1 suggests that the interaction triggers a conformational change within the MUPP1 protein. Moreover, 5-HT(2A) and 5-HT(2B), sharing the C-terminal EX(V/I)SXV sequence with 5-HT(2C) receptors, also bind MUPP1 PDZ domains in vitro. The highest MUPP1 mRNA levels were found in all cerebral cortical layers, the hippocampus, the granular layer of the dentate gyrus, as well as the choroid plexus, where 5-HT(2C) receptors are highly enriched. We propose that MUPP1 may serve as a multivalent scaffold protein that selectively assembles and targets signaling complexes.
Becamel
C
C
Biofrontera Pharmaceuticals AG, Hemmelratherweg 201, 51377 Leverkusen, Germany.
Figge
A
A
Poliak
S
S
Dumuis
A
A
Peles
E
E
Bockaert
J
J
Lubbert
H
H
Ullmer
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D002831:Choroid Plexus / Q000378:metabolism; D016384:Consensus Sequence; D000939:Epitopes / Q000737:chemistry; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D051381:Rats; D044402:Receptor, Serotonin, 5-HT2A; D044403:Receptor, Serotonin, 5-HT2B; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014162:Transfection; D014721:Vesicular stomatitis Indiana virus / Q000737:chemistry
D002352:Carrier Proteins; D000939:Epitopes; D047908:Intracellular Signaling Peptides and Proteins; C491749:Mpdz protein, rat; D044402:Receptor, Serotonin, 5-HT2A; D044403:Receptor, Serotonin, 5-HT2B; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; D011994:Recombinant Proteins