SLN promotes interaction between SERCA1 and sAnk1.
A, COS7 cell extracts transfected as indicated below each panel were subjected to IP with antibodies specific to SERCA1. Transfections were performed using a [C]final of 1 μg/ml. B, quantitative densitometry analysis was performed to assess coIP between SERCA1 and sAnk1 in the presence or absence of FLAG-SLN. There was a 2.6-fold increase in coIP of sAnk1 when it was coexpressed with FLAG-SLN. C, increasing the amount of cDNA encoding FLAG-SLN, as indicated below each panel, increased interaction between SERCA1 and sAnk1. D, increasing the amount of cDNA encoding sAnk1-FLAG had no effect on coIP of SERCA1 and FLAG-SLN. E and F, graphical representation of densitometric analysis of experiments shown in C and D, respectively. Linear regression shows a significant increase in coIP of sAnk1 with SERCA1 with increasing SLN expression (E: m = 0.672 ± 0.15; p = 0.0018; n = 2), whereas increasing sAnk1 expression had no significant effect on coIP of SLN with SERCA1 (F: m = 0.0404 ± 0.53; p = 0.46 (upper band) and m = 0.040 ± 0.05080; p = 0.45 (lower band; n = 2). Data represent slope ± S.E.