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Fig. 5. Tissue distribution and localisation of xClC-5. (A) The tissue distribution of xClC-5 was examined in Xenopus with anti-ClC-5 antibodies described in
Ref. [81]. Bands of different molecular weights could be detected in xClC-5 cRNA-injected oocytes, kidney, intestine, and brain. The highest band (130 kDa,
arrowhead) was predominant in cRNA-injected oocytes and kidney and is likely to correspond to a highly glycosylated form of xClC-5. A faint band was seen
in heart. Brain and intestine presented a predominant lower band (at about 85 kDa, arrowhead). The same pattern of bands was observed with our antibody
(antibody described in Ref. [66]). The 50 kDa band observed in oocytes corresponds probably to a nonspecific band as it can also be observed in noninjected
control oocytes (data not shown). Methods are as described in Ref. [66]. Briefly, 50 Ag of Xenopus oocytes and 150 Ag of Xenopus tissues were separated by
SDS-PAGE, electrotransfered onto nitrocellulose membrane, and incubated overnight with the anti-ClC-5 antibodies, kindly provided by T. Jentsch. (Our
unpublished data.) (B) Immunolocalisation of xClC-5 in A6 cells grown on coverslips. Cells were fixed in 2% paraformaldehyde. Primary anti-ClC-5
antibodies were described previously [66] and used at 1:50. Secondary antibodies were FITC-conjugated, and were used at 1:300. Bar: 10 Am. (Our
unpublished data.) (C) Functional model for ClC-5 (model modified from Ref. [104]). ClC-5 co-localises with proton pumps in early endosomes in proximal
tubule cells [104]. Parallel functioning of the proton pumps and ClC-5 channels allows the acidification of early endosomes involved in recycling and
degradation of apical receptors and reabsorption of low molecular weight proteins. |
