In searching for a basolateral membrane water transporter in rat kidney with homology to channel forming integral protein (CHIP28), water channel-collecting duct (WCH-CD), and mercurial-insensitive water channel (MIWC), we clotted a new member of the major intrinsic protein family (CLIP GLycerol Intrinsic Protein). GLIP cDNA had an 855-base pair open reading frame encoding a 30.5-kDa protein with 19-23% amino acid identity to the water channels and 36% identity to the bacterial glycerol facilitator GlpF. Northern blot analysis showed a 5.5-kilobase mRNA encoding CLIP in kidney, brain, and lung; RT-PCR/Southern blot analysis indicated expression of GLIP in kidney, brain, lung, eye, colon, stomach, and skeletal muscle, but not in heart, liver, and spleen. In situ hybridization in rat kidney showed CLIP mRNA expression in medullary collecting duct. Immunofluorescence with a peptide derived polyclonal antibody showed CLIP protein expression in basolateral membrane of kidney collecting duct principal cells and brain meningeal cells. Functional measurements in Xenopus oocytes expressing CLIP cRNA showed a >2O-fold increase in [H-3]glycerol uptake compared with water injected oocytes; glycerol uptake was inhibited 88% by diisothiocyanodisulfonic stilbene (0.2 mM) and 36% by phloretin (0.25 mM). CLIP did not function as a transporter for water, urea, inositol, glucose, lactate, and monovalent ions. Glycerol uptake in oocytes expressing CHIP28 and MIWC was not different from that in water-injected controls. CLIP represents the first mammalian water channel homolog that selectively transports a solute other than water. The physiological substrate(s) and role(s) of CLIP remain to be elucidated.

Cloning of a water channel homolog expressed in brain meningeal cells and kidney collecting duct that functions as a stilbene-sensitive glycerol transporter

FRIGERI, Antonio;
1994-01-01

Abstract

In searching for a basolateral membrane water transporter in rat kidney with homology to channel forming integral protein (CHIP28), water channel-collecting duct (WCH-CD), and mercurial-insensitive water channel (MIWC), we clotted a new member of the major intrinsic protein family (CLIP GLycerol Intrinsic Protein). GLIP cDNA had an 855-base pair open reading frame encoding a 30.5-kDa protein with 19-23% amino acid identity to the water channels and 36% identity to the bacterial glycerol facilitator GlpF. Northern blot analysis showed a 5.5-kilobase mRNA encoding CLIP in kidney, brain, and lung; RT-PCR/Southern blot analysis indicated expression of GLIP in kidney, brain, lung, eye, colon, stomach, and skeletal muscle, but not in heart, liver, and spleen. In situ hybridization in rat kidney showed CLIP mRNA expression in medullary collecting duct. Immunofluorescence with a peptide derived polyclonal antibody showed CLIP protein expression in basolateral membrane of kidney collecting duct principal cells and brain meningeal cells. Functional measurements in Xenopus oocytes expressing CLIP cRNA showed a >2O-fold increase in [H-3]glycerol uptake compared with water injected oocytes; glycerol uptake was inhibited 88% by diisothiocyanodisulfonic stilbene (0.2 mM) and 36% by phloretin (0.25 mM). CLIP did not function as a transporter for water, urea, inositol, glucose, lactate, and monovalent ions. Glycerol uptake in oocytes expressing CHIP28 and MIWC was not different from that in water-injected controls. CLIP represents the first mammalian water channel homolog that selectively transports a solute other than water. The physiological substrate(s) and role(s) of CLIP remain to be elucidated.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/42537
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 181
  • ???jsp.display-item.citation.isi??? 179
social impact