Abstract
Kv1.l and Kv1.4 potassium channels have different pore region determinants that were found to affect their cell-surface levels positively and negatively [Zhu, Watanabe, Gomez and Thornhill (2001) J. Biol. Chem. 276, 39419-39427; Zhu, Watanabe, Gomez and Thornhill (2003) J. Biol. Chem. 278, 25558-25567; Zhu, Watanabe, Gomez and Thornhill (2003) Biochem. J. 375, 761-768], In the present study, we focused on the deep pore region of Kv1 members to test whether a cell-surface trafficking code was dictated by two amino acids. Kv1 channels with a threonine/lysine amino acid pair in a non-contiguous pore region promoted high surface levels, whereas a serine/tyrosine amino acid pair inhibited high surface expressioa by inducing a high level of partial endoplasmic reticulum retention. Our work suggests that a possible positive trafficking amino acid pair coding here for the Kv1 subfamily is Thr/Lys > Thr/Val > Thr/Tyr > Thr/Arg ∼ Thr/His > Ser/Val > Ser/Tyr > Ser/Lys. The Kv1 trafficking code was not transferable to a Kv2 family member and thus it appears that it only governs surface levels in the context of its Kv1 native pore loop region and/or its S5 and S6 regions. All members of a given Kv2, Kv3 or Kv4 potassium channel subfamily have identical amino acids at similar positions in their deep pore regions (Thr/Tyr or Thr/Val), which suggests that any difference in surface levels among members is not dictated by these amino acids. Thus a major determinant for cell-surface trafficking of Kv1 potassium channels is an amino acid pair in their deep pore regions, whereas the cell-surface levels of a given Kv2, Kv3 or Kv4 subfamily member are probably not affected by these amino acids.
Original language | English (US) |
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Pages (from-to) | 355-362 |
Number of pages | 8 |
Journal | Biochemical Journal |
Volume | 388 |
Issue number | 1 |
DOIs | |
State | Published - May 15 2005 |
Externally published | Yes |
Keywords
- Amino acid pair
- Cell-surface expression
- Deep pore regions
- Endoplasmic reticulum
- Potassium channel
- Trafficking
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology