Regulators of G protein signaling (e.g., RGS3; OMIM 602189) act as GTPase-activating and -enhancing proteins that bind to the
alpha subunits of heterotrimeric G proteins. Although their RGS domains are diagnostic and highly homologous, RGS
proteins are highly divergent at their N and C termini. GAIP (OMIM 605071) is a membrane-anchored RGS protein located on
clathrin-coated vesicles involved in membrane trafficking. By screening a rat pituitary cell library using a yeast 2-hybrid
system with GAIP as bait, and by searching an EST database, De Vries et al. (1998) obtained a cDNA encoding C19ORF3,
which they called GIPC (GAIP-interacting protein, C terminus). Sequence analysis predicted that the 36-kD, hydrophilic
C19ORF3 protein contains 333 amino acids, including multiple phosphorylation sites and an 80- to 100-amino acid PDZ
domain. PDZ domain-containing proteins typically recognize C-terminal amino acids and are involved
in protein network signaling.
General function
Intracellular protein transport
Comment
Cellular localization
Plasma membrane
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Ovarian function
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Expression regulated by
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Ovarian localization
Luteal cells
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Endocrine meeting [P3-223] GIPC, a PDZ Domain Protein Is a Binding Partner for the Human Lutropin Receptor.
Takashi Hirakawa, Colette Galet, Mario Ascoli Pharmacology, The Univ of Iowa, Iowa City, IA