TY - JOUR
T1 - 26 Amino acids of an extracellular domain of the Na,K-ATPase α-subunit are sufficient for assembly with the Na,K-ATPase β-subunit
AU - Lemas, M. Victor
AU - Hamrick, Maura
AU - Takeyasu, Kunio
AU - Fambrough, Douglas M.
N1 - Copyright:
Copyright 2005 Elsevier B.V., All rights reserved.
PY - 1994/3/18
Y1 - 1994/3/18
N2 - Chimeric cDNAs encoding a sarcoplasmic/endoplasmic reticulum Ca-ATPase (SERCA1) and regions of the Na,K-ATPase α-subunit were constructed to seek the minimal region of the α-subunit sufficient for assembly with the Na,K- ATPase β-subunit. cDNAs encoding a chimera and the chicken β-subunit were coexpressed in mammalian cells and assembly was assayed by immune precipitation of the chimeric subunit with a monoclonal antibody to the chicken β-subunit. A chimera containing 26 amino acyl residues of the Na,K- ATPase α1-subunit (NDVEDSYGQQWTFEQRKIVEFTCHTA) (Asn894 to Ala919) that replaced the corresponding avian SERCA1 Ca-ATPase amino acyl residues (Thr871 to Thr898) was able to assemble with the chicken β-subunit. This α-subunit region is predicted to be extracellular, located between membrane-spanning domains 7 and 8 (H7-H8). Chimeras that assembled with full- length β-subunit also assembled with a β-subunit chimera that retained only the ectodomain of the chicken β1-subunit. These results suggest that the Na,K-ATPase α-subunit has the same topology in the membrane as the sarcoplasmic reticulum Ca-ATPase, probably with 10 membrane-spanning domains, and that the aminoacyl residues between membrane domains H7 and H8 are involved in assembly with the β-subunit in the extracellular/lumenal space.
AB - Chimeric cDNAs encoding a sarcoplasmic/endoplasmic reticulum Ca-ATPase (SERCA1) and regions of the Na,K-ATPase α-subunit were constructed to seek the minimal region of the α-subunit sufficient for assembly with the Na,K- ATPase β-subunit. cDNAs encoding a chimera and the chicken β-subunit were coexpressed in mammalian cells and assembly was assayed by immune precipitation of the chimeric subunit with a monoclonal antibody to the chicken β-subunit. A chimera containing 26 amino acyl residues of the Na,K- ATPase α1-subunit (NDVEDSYGQQWTFEQRKIVEFTCHTA) (Asn894 to Ala919) that replaced the corresponding avian SERCA1 Ca-ATPase amino acyl residues (Thr871 to Thr898) was able to assemble with the chicken β-subunit. This α-subunit region is predicted to be extracellular, located between membrane-spanning domains 7 and 8 (H7-H8). Chimeras that assembled with full- length β-subunit also assembled with a β-subunit chimera that retained only the ectodomain of the chicken β1-subunit. These results suggest that the Na,K-ATPase α-subunit has the same topology in the membrane as the sarcoplasmic reticulum Ca-ATPase, probably with 10 membrane-spanning domains, and that the aminoacyl residues between membrane domains H7 and H8 are involved in assembly with the β-subunit in the extracellular/lumenal space.
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M3 - Article
C2 - 7907590
AN - SCOPUS:0028289934
SN - 0021-9258
VL - 269
SP - 8255
EP - 8259
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 11
ER -