title: PDZK1 regulates organic anion transporting polypeptide Oatp1a in mouse small intestine.
abstract: Recent studies indicate that various members of the organic anion transporting polypeptide (OATP) family are expressed on apical membranes of the small intestine. In the present study, we investigated possible interaction of Oatp with the PDZ protein PDZK1 in mouse small intestine, using [³H]estrone-3-sulfate (E3S) as a typical substrate. After intraduodenal administration, the level of [³H]E3S appearing in the portal vein of pdzk1 gene knockout (pdzk1(-/-)) mice was much lower than that in wild-type mice. Lower intestinal absorption of [³H]E3S in pdzk1(-/-) mice was confirmed in Ussing-type chamber experiments, which showed smaller uptake of [³H]E3S from the apical side in intestinal tissues of pdzk1(-/-) mice compared with wild-type mice. The kinetics and inhibition profile of [³H]E3S uptake in the Ussing-type chamber were similar to those in HEK293 cells stably expressing Oatp1a5, suggesting involvement of Oatp1a5 in [³H]E3S uptake. Immunoreactivity to anti-Oatp1a antibody was colocalized with PDZK1 in the small intestine of wild-type mice, whereas apical localization of Oatp1a protein was reduced in pdzk1(-/-) mice. An immunoprecipitation study revealed physical interaction of PDZK1 with Oatp1a. Thus, PDZK1 appears to act as an adaptor for Oatp1a. This is the first demonstration of a regulatory protein directly interacting with small-intestinal OATP.
authors.affiliation: Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Sugiura
authors.forename: Toru
authors.initials: T
authors.lastname: Otake
authors.forename: Takuya
authors.initials: T
authors.lastname: Shimizu
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Wakayama
authors.forename: David L
authors.initials: DL
authors.lastname: Silver
authors.forename: Rie
authors.initials: R
authors.lastname: Utsumi
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nishimura
authors.forename: Shoichi
authors.initials: S
authors.lastname: Iseki
authors.forename: Noritaka
authors.initials: N
authors.lastname: Nakamichi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kubo
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuji
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000818:Animals; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology*; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D018345:Mice, Knockout; D027701:Organic Cation Transport Proteins / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C464433:Oatp2 protein, mouse; D027701:Organic Cation Transport Proteins; C514896:PDZK1 protein, mouse; D004970:Estrone; C017296:estrone sulfate