Aquaporin x5 of 273 aas and 6 TMSs, Aqp-x5. The sequence reveals a mercurial-sensitive cysteine and a putative phosphorylation motif site for protein kinase A at Ser-257 (Kubota et al. 2006). A swelling assay using Xenopus oocytes revealed that AQP-x5 facilitated water permeability. Expression of AQP-x5 mRNA was restricted to the skin, brain, lungs and testes. Immunofluorescence and immunoelectron microscopical studies using an anti-peptide antibody (ST-156) against the C-terminal region of the AQP-x5 protein revealed the presence of immunopositive cells in the skin, with the label predominately localized in the apical plasma membrane of the secretory cells of the small granular glands. These glands are unique both in being close to the epidermal layer of the skin and in containing mitochondria-rich cells with vacuolar H+-ATPase dispersed among its secretory cells. Results from immunohistochemical experiments on the mucous or seromucous glands of several other anurans verified this result (Kubota et al. 2006).
|Xenopus laevis (African clawed frog) 
|Number of TMSs:
1: MRNEICSLAF VRAVFAEFLA TMIFVFLGLG SALSWKPSLP NVLQISLAFG LAISTLVQAF
61: GHVSGAHINP AVTVAFLIGC HISFLRALFY IIAQLVGAIA GAAIVRAVAP LDVRGNLAIN
121: AINSGSPGQA CAVELFLTFQ LVLCVFASTD SRRSDNVGSP ALSIGLSVTV GHLLGIYLTG
181: CSMNPARSFG PAAITGIFTD HWVFWIGPLV GGIMASLFYN YIFFPHKKSF SDRLAILKGT
241: YQPEEAWDNK HEQRRQSVEL YSAHPLPKVI DKF