Ms. Wu et al., ROLE OF F-ACTIN IN THE ACTIVATION OF NA-K+-CL- COTRANSPORT BY FORSKOLIN AND VASOPRESSIN IN MOUSE KIDNEY CULTURED THICK ASCENDING LIMB CELLS(), The Journal of membrane biology, 142(3), 1994, pp. 323-336
The influence of microtubules and F-actin on Na+-K+-Cl- cotransport wa
s investigated in cultured cells derived from outer-medullary thick as
cending limb tubules microdissected from the mouse kidney. The culture
d cells contained Tamm-Horsfall protein, produced cAMP in response to
dD-arginine vasopressin (dD-AVP), isoproterenol, prostaglandin E(2) an
d forskolin (FK), and exhibited an ouabain-resistant furosemide-sensit
ive (Or-Fs) component of Rb-86(+) influx mediated by the Na+-K+-Cl- co
transporter. Both FK and dD-AVP stimulated the Or-Fs component of Rbinflux. Neither agent altered the tubulin and cytokeratin networks nor
the shape of the tight junction using a specific anti-ZO-1 antibody.
In contrast, they did induce a marked redistribution of F-actin to the
periphery of the cells delineating the tight junctions. Preincubation
of the cells with nocodazole, to disrupt microtubules, did not alter
the FK-or dD-AVP-elicited Or-Fs Rb+ influx. In contrast, phalloidin an
d NBD-phallicidin, which stabilize F-actin, markedly impaired the stim
ulation of Na+-K+-Cl(-)cotransport by FK or dD-AVP, without affecting
the Na+-K+ ATPase pumps and the rate constant of Cl-36(-) and Rb-86(+)
efflux. These results strongly suggested that cAMP-stimulated Na+-K+-
Cl- cotransport is linked to F-actin in renal TAL cells.