Ion channels in K562 cells. Relation with the CFTR and MDR proteins.

ASSEF Y., DAMIANO A., ZOTTA E., IBARRA C. Y KOTSIAS BA.

San Francisco, Estados Unidos

Congreso; 46th Biophysical Society Annual Meeting; 2002

Biophysical Society

We used the cell line K562 obtained from a chronic myeloid leukemia for the study of ion channels with patch clamp and RT-PCR techniques. Our objectives were the assessment of the expression of integral proteins such as the CFTR (cystic fibrosis transmembrane regulator) and MDR (multidrug resistance), their pattern of expression and to establish their function as ion channels. The amplified products showed two bands of 300 bp and 170 bp corresponding to CFTR and MDR 1. In the inside-out configuration, forskolin (20 uM), an activator of the adenylate cyclase turns on ion channel activity with a linear current-voltage relationship and a conductance of 12 pS which is not affected by replacement of Na+ by NMDG. These channels present a lower permeability (P) for gluconate and fluorure (F-) than Cl-, with relative permeabilities Pgluconate/PCl and PF/PCl of 0.24 and 0.20 respectively. Glibenclamide (100 uM) added to the bath diminished the open probability. The presence of an anion channel with a conductance similar to CFTR, with no rectification and blocked by glibenclamide suggests that one of the products obtained through RT-PCR may have a functional expression in K562 cells, with a pattern not complementary with MDR (Supported by Ministerio de Salud de Argentina).