Mosquito (Aedes aegypti ) aquaporin, present in tracheolar cells, transports water, not glycerol, and forms orthogonal arrays in Xenopus oocyte membranes.
Previous results showed that mRNA encoding a putative aquaporin (AQP) (GenBank accession number AF218314) is present in the tracheolar cells associated with female Aedes aegypti Malpighian tubules. In this study, immunohistochemistry detected the protein, AeaAQP, also in tracheolar cells, suggesting its involvement in water movement in the respiratory system. When expressed in Xenopus oocytes, AeaAQP increased the osmotic water permeability from 15 x 10(-6) to 150 x 10(-6) m x s-1, which was inhibited by mercury ions. No permeability to glycerol or other solute was observed. AeaAQP expressed in oocytes was solubilized as a homotetramer in nondenaturing detergent as deduced from velocity centrifugation on density gradients. Phylogenetic analysis of MIP (major intrinsic protein) family sequences shows that AeaAQP clusters with other native orthogonal array forming proteins. Specific orthogonal arrays were detected by freeze-fracture analysis of AeaAQP oocyte membranes. We conclude that, in tracheolar cells of A. aegypti, AeaAQP is probably a highly water-permeable homotetrameric MIP which natively can form 2D crystals.
Duchesne
Laurence
L
UMR CNRS 6026, Interactions Cellulaires et Moléculaires, Université de Rennes I, Rennes, France.
Hubert
Jean-François
JF
Verbavatz
Jean-Marc
JM
Thomas
Daniel
D
Pietrantonio
Patricia V
PV
D000330:Aedes / Q000502:physiology*; D000818:Animals; D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D017931:DNA Primers / Q000737:chemistry; D005260:Female; D005614:Freeze Fracturing; D005990:Glycerol / Q000378:metabolism*; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008317:Malpighian Tubules / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D014132:Trachea / Q000378:metabolism*; D014867:Water / Q000378:metabolism*; D014982:Xenopus laevis
D020346:Aquaporins; D017931:DNA Primers; D012333:RNA, Messenger; D014867:Water; D005990:Glycerol