Interaction sites among phospholamban, sarcolipin, and the sarco(endo)plasmic reticulum Ca(2+)-ATPase.
A robust cross-link between Gln(23) in phospholamban (PLN) and Lys(328) in the sarco(endo)plasmic reticulum Ca(2+) ATPase (SERCA1a) is formed in the presence or absence of oxidant and is susceptible to both PLN phosphorylation and SERCA1a Ca(2+) binding. This cross-link provides precisely the evidence needed to support our earlier proposal that collision of the PLN transmembrane helix at Asn(27) with the cytosolic extension of M4 at Leu(321) leads to unwinding of the helix. In a study of site-specific interactions among PLN, sarcolipin (SLN), and SERCA1a, we determined that mutations of some specific amino acids in PLN or SLN diminish either the super-inhibition imposed on SERCA1a function by the PLN-SLN binary complex or the physical interactions between PLN and SLN or both. These results have led to a revision of our earlier model for the PLN-SLN-SERCA1a complex.
Morita
Takashi
T
Banting and Best Department of Medical Research, University of Toronto, Charles H. Best Institute, 112 College Street, Toronto, Ont., Canada.
Hussain
Dawar
D
Asahi
Michio
M
Tsuda
Takeo
T
Kurzydlowski
Kazimierz
K
Toyoshima
Chikashi
C
Maclennan
David H
DH
D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D003198:Computer Simulation; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008954:Models, Biological; D008956:Models, Chemical; D009124:Muscle Proteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011510:Proteolipids / Q000737:chemistry / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000737:chemistry / Q000378:metabolism*; D000099211:Phospholamban
D002135:Calcium-Binding Proteins; D009124:Muscle Proteins; D011510:Proteolipids; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D000099211:Phospholamban; C077258:sarcolipin