Title : Glycosylation and cell surface expression of Kv1.2
potassium channel are regulated by
determinants in the pore
region
Abstract :
- Voltage-gated K(+) channels contain six membrane spanning segments and a pore-forming domain
- We used site-directed mutation to examine the role of specific amino acids in the extracellular region of the pore in Kv1.2
- When expressed in CHO cells, a K(+) current was not observed for mutants S356A, S360A, T383A and T384A
- However, coexpression of the Kvbeta2 subunit and the S360A mutant resulted in a robust peak current
- Immunocytochemistry for Kv1.2 showed staining throughout the cytoplasm in cells coexpressing the beta2 and S360A, whereas only the perinuclear region was stained in cells expressing the S360A mutant
- Western blotting revealed that the major immunoreactive protein in wild-type- and mutant-expressing cells is 60-kDa, but 87-kDa bands were also detected in cells expressing wild-type Kv1.2 and cells coexpressing beta2and S360A
- These results suggest that amino acids in the pore region help regulate ion permeability or cellular trafficking by affecting glycosylation of Kv1.2