Naslov
NHE3 is targeted to the basolateral plasma membrane in straight proximal tubule segments of colchicine-treated rats

Autori
Herak-Kramberger, Carol M. ; Ljubojevic, Marija ; Biemesderfer, Daniel ; Brown, Dennis ; Sabolic, Ivan

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Journal of the American Society of Nephrology / - Washington (MD) : The American Society of Nephrology/Lippincott Williams&Wilkins, 2000

Skup
33rd Annual Meeting of the Americal Society of Nephrology

Mjesto i datum
Toronto, Kanada, 10.10.2000. - 16.10.2000

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
colchicine; sodium-proton exchanger; microtubules; vesicle trafficking

Sažetak
The structural and functional polarity of epithelial cells is maintained by vesicle-mediated and microtubule (MT)-dependent trafficking of various components between the cell membrane and intracellular organelles. In colchicine (C)-treated rats, depolymerization of MT in renal proximal tubule cells (PTC) causes disruption of vesicle trafficking and recycling, and redistribution of some brush-border membrane (BBM) proteins into cytoplasmic vesicles. We recently showed that following MT depolymerization in rats, the BBM aquaporin-1 (AQP1), a protein common to cells of convoluted (CPT) and straight (SPT) PT segments, was translocated from the BBM into intracellular vesicles in the CPT but not in the SPT (Eur. J. Physiol. 439:321, 2000). To further document these segmental differences, we studied the effect of MT loss on the distribution of BBM sodium-proton exchanger (NHE3) by immunofluorescence in tissue sections and by immunobloting in BBM isolated from C-treated rats (3.2 mg/kg, i.p., a single dose 12h before sacrifice). In control rats, NHE3 in the CPT was labeled strongly in the BBM and weakly in subapical endosomes, whereas in the SPT, NHE3 was present in the BBM and in numerous, randomly scattered cytoplasmic vesicles. In the CPT of C-treated rats, a dramatic redistribution of the antigen from the BBM into intracellular vesicles, and a loss of the respective 80 kDa protein band in isolated cortical BBM, occured. In the SPT, however, the abundance of NHE3 in the BBM was not visibly changed. The NHE3-positive intracellular vesicles vanished, and the antigen was clearly detectable in the basolateral plasma membrane (BLM). These data suggest that recycling of NHE3 in the SPT may include MT-independent targeting to the BLM, followed by the MT-dependent, vesicle-mediated transcytosis to the BBM.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

POVEZANOST RADA