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Deletion of NH 2 − and COOH‐terminal sequences destroys function of the Ca 2+ ATPase of rabbit fast‐twitch skeletal muscle sarcoplasmic reticulum
Author(s) -
Skerjanc Ilona S.,
Clarke David M.,
Loo Tip W.,
MacLennan David H.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81633-b
Subject(s) - endoplasmic reticulum , skeletal muscle , chemistry , atpase , transmembrane protein , mutant , microbiology and biotechnology , transmembrane domain , membrane , biophysics , enzyme , biochemistry , biology , gene , anatomy , receptor
Deletion mutants of the Ca 2+ ATPase of rabbit fast‐twitch skeletal muscle sarcoplasmic reticulum (SERCA1a) were constructed and expressed in COS‐1 cells. The mutants were expressed at levels 7‐ to 15‐fold lower than the wild‐type and were inactive. In vitro transcription‐translation‐insertion experiments showed that deletion of transmembrane sequences M 1 and M 2 , but not of M 8 , M 9 , M 10 or the NH 2 − terminal 30 amino acids inhibited the stable insertion of the enzyme into the membrane. Thus there was no correlation between loss of function and membrane insertion. A signal sequence for membrane insertion may exist in M 1 and M 2 .