@entity30353 and @entity9400 @entity972 channels are expressed in brain as mature glycoproteins that are trans-Golgi glycosylated. When expressed in cell lines these homomers had very different trans-Golgi glycosylation efficiencies and cell surface expression levels with @entity30353 > @entity9400 for both parameters (Zhu, J., Watanabe, I., Gomez, B., and Thornhill, W. B. (2001) J. Biol. Chem. 276, 39419-39427). This previous study identified determinants in the outer pore region of @entity30353 and @entity9400 that positively and negatively, respectively, affected these events when expressed as homomers. Here we investigated which subunit exhibited positive or negative effects on these processes when expressed as heteromers. @entity30353 / @entity9400 heteromers, by coexpression or expression as tandem-linked heteromers, were expressed on the cell surface at approximately 20-fold lower levels versus @entity30353 homomers but they were trans-Golgi glycosylated. The lower @entity30353 / @entity9400 expression level was not rescued by Kvbeta 2.1 subunits. Thus @entity9400 inhibited high cell surface expression and partially retained the heteromer in the endoplasmic reticulum, whereas @entity30353 stimulated trans-Golgi glycosylation. The subunit determinants and cellular events responsible for these differences were investigated. In a @entity30353 / @entity9400 heteromer, the @entity9400 pore was a major negative determinant, and it inhibited high cell surface expression because it induced high partial endoplasmic reticulum retention and it decreased protein stability. Other @entity9400 regions also inhibited high surface expression of heteromers. The @entity9400 C terminus induced partial Golgi retention and contributed to a decreased protein stability, whereas the @entity9400 N terminus contributed to only a decreased protein stability. Thus a neuron may regulate its cell surface K+ channel protein levels by different Kv1 subfamily homomeric and heteromeric combinations that affect intracellular retention characteristics and protein stability.

Heteromeric Kv1 XXXX channel expression: amino acid determinants involved in processing and trafficking to the cell surface.

@entity30353 :: ('3739', 'Gene') :: ['Kv1.4'] @entity9400 :: ('3736', 'Gene') :: ['Kv1.1'] @entity972 :: ('MESH:D011188', 'Chemical') :: ['potassium']
@entity972 :: (MESH:D011188,Chemical) :: ['potassium']
