TY - JOUR
T1 - Molecular cloning and expression of a member of the aquaporin family with permeability to glycerol and urea in addition to water expressed at the basolateral membrane of kidney collecting duct cells
AU - Ishibashi, Kenichi
AU - Sasaki, Sei
AU - Fushimi, Kiyohide
AU - Uchida, Shinichi
AU - Kuwahara, Michio
AU - Saito, Hideyuki
AU - Furukawa, Tetsushi
AU - Nakajima, Kichiro
AU - Yamaguchi, Yumi
AU - Gojobori, Takashi
AU - Marumo, Fumiaki
PY - 1994/7/5
Y1 - 1994/7/5
N2 - Water transport in highly water-permeable membranes is conducted by water- selective pores-namely, water channels. The recent cloning of water channels revealed the water-selective characteristics of these proteins when expressed in Xenopus oocytes or reconstituted in liposomes. Currently, it is assumed that the function of water channels is to transport only water. We now report the cloning of a member of the water channel that also transports nonionic small molecules such as urea and glycerol. We named this channel aquaporin 3 (AQP3) for its predominant water permeability. AQP3 has amino acid sequence identity with major intrinsic protein (MIP) family proteins including AQP- channel-forming integral membrane protein, AQP-collecting duct, MIP, AQP-γ tonoplast intrinsic protein, nodulin 26, and glycerol facilitator (33-42%). Thus, AQP3 is an additional member of the MIP family. Osmotic water permeability of Xenopus oocytes measured by videomicroscopy was 10-fold higher in oocytes injected with AQP3 transcript than with water-injected oocytes. The increase in osmotic water permeability was inhibited by HgCl2, and this effect was reversed by a reducing agent, 2-mercaptoethanol. Although to a smaller degree, AQP3 also facilitated the transport of nonionic small solutes such as urea and glycerol, while the previously cloned water channels are permeable only to water when expressed in Xenopus oocytes. AQP3 mRNA was expressed abundantly in kidney medulla and colon. In kidney, it was exclusively immunolocalized at the basolateral membrane of collecting duct cells. AQP3 may function as a water and urea exit mechanism in antidiuresis in collecting duct cells.
AB - Water transport in highly water-permeable membranes is conducted by water- selective pores-namely, water channels. The recent cloning of water channels revealed the water-selective characteristics of these proteins when expressed in Xenopus oocytes or reconstituted in liposomes. Currently, it is assumed that the function of water channels is to transport only water. We now report the cloning of a member of the water channel that also transports nonionic small molecules such as urea and glycerol. We named this channel aquaporin 3 (AQP3) for its predominant water permeability. AQP3 has amino acid sequence identity with major intrinsic protein (MIP) family proteins including AQP- channel-forming integral membrane protein, AQP-collecting duct, MIP, AQP-γ tonoplast intrinsic protein, nodulin 26, and glycerol facilitator (33-42%). Thus, AQP3 is an additional member of the MIP family. Osmotic water permeability of Xenopus oocytes measured by videomicroscopy was 10-fold higher in oocytes injected with AQP3 transcript than with water-injected oocytes. The increase in osmotic water permeability was inhibited by HgCl2, and this effect was reversed by a reducing agent, 2-mercaptoethanol. Although to a smaller degree, AQP3 also facilitated the transport of nonionic small solutes such as urea and glycerol, while the previously cloned water channels are permeable only to water when expressed in Xenopus oocytes. AQP3 mRNA was expressed abundantly in kidney medulla and colon. In kidney, it was exclusively immunolocalized at the basolateral membrane of collecting duct cells. AQP3 may function as a water and urea exit mechanism in antidiuresis in collecting duct cells.
KW - glycerol facilitator
KW - major intrinsic protein family
KW - urine concentration
UR - http://www.scopus.com/inward/record.url?scp=0028227129&partnerID=8YFLogxK
U2 - 10.1073/pnas.91.14.6269
DO - 10.1073/pnas.91.14.6269
M3 - Article
C2 - 7517548
AN - SCOPUS:0028227129
SN - 0027-8424
VL - 91
SP - 6269
EP - 6273
JO - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
IS - 14
ER -