SUMO1-dependent modulation of SERCA2a in heart failure

Abstract

SR Ca2+ ATPase 2a (SERCA2a) is a critical ATPase responsible for Ca2+ re-uptake during excitation-contraction coupling. Impaired SR Ca2+ uptake resulting from decreased expression and reduced activity of SERCA2a is a hallmark of heart failure (HF)1. Accordingly, restoration of SERCA2a expression by gene transfer has proven to be effective in improving cardiac function in HF patients2 as well as in animal models3. The small ubiquitin-related modifier (SUMO) can be conjugated to lysine residues of target proteins4, which is involved in most cellular process5. Here, we show that SERCA2a is SUMOylated at lysine 480 and 585 and that this SUMOylation is essential for preserving SERCA2a ATPase activity and stability. The levels of SUMO1 and SUMOylation of SERCA2a itself were greatly reduced in failing hearts. SUMO1 restitution by adeno-associated virus-mediated gene delivery maintained protein abundance of SERCA2a and significantly improved cardiac function in HF mice. This effect was comparable to SERCA2a gene delivery. Moreover, SUMO1 overexpression in isolated cardiomyocytes augmented contractility and accelerated Ca2+ decay. Transgene-mediated SUMO1 overexpression rescued pressure overload-induced cardiac dysfunction concomitantly with increased SERCA2a function. By contrast, down-regulation of SUMO1 using shRNA accelerated pressure overload-induced deterioration of cardiac function and was accompanied by decreased SERCA2a function. However, knockdown of SERCA2a resulted in severe contractile dysfunction both in vitro and in vivo, which was not rescued by overexpression of SUMO1. Taken together, our data show that SUMOylation is a critical post-translational modification that regulates SERCA2a function and provides a platform for the design of novel therapeutic strategies for HF.

Characterizing Phospholamban to Sarco(endo)plasmic Reticulum Ca2+-ATPase 2a (SERCA2a) Protein Binding Interactions in Human Cardiac Sarcoplasmic Reticulum Vesicles Using Chemical Cross-linking

“…A drug that acts like 2D12, preventing PLB binding to SERCA2a, might be expected to produce large increases in cardiac contraction and relaxation in failed human myocardium (9). Although not the focus of this study, in light of our current results, we feel it important to address the very recent study by Kho et al (30) in which it was suggested that SUMOylation of SERCA2a in human hearts by SUMO1 increases Ca 2ϩ pump stability and Ca 2ϩ -ATPase activity by enhancing ATP binding affinity (30). The authors also suggested that the level of SUMOylation of SERCA2a is reduced in failing human hearts and that restoration of SERCA2a SUMOylation may be a viable means of treating heart failure (30).…”

“…Although not the focus of this study, in light of our current results, we feel it important to address the very recent study by Kho et al (30) in which it was suggested that SUMOylation of SERCA2a in human hearts by SUMO1 increases Ca 2ϩ pump stability and Ca 2ϩ -ATPase activity by enhancing ATP binding affinity (30). The authors also suggested that the level of SUMOylation of SERCA2a is reduced in failing human hearts and that restoration of SERCA2a SUMOylation may be a viable means of treating heart failure (30). However, in our present study with normal and failed human hearts, no 150-kDa mobility form that might correspond to SUMOylated SERCA2a was detected.…”

The neuroprotective agent Rasagiline mesylate attenuates cardiac remodeling after experimental myocardial infarction

“…Inhibition of MAO‐B results in reduced formation of H 2 O 2 and aldehydes, two molecules that are known to stimulate mitochondrial and myocardial damage 41. Furthermore, in context with oxidative stress, we also explored SUMO‐1 which has been found to be highly relevant in the response to cellular stress and rescues SERCA2a ATPase (cardiac isoform of sarcoplasmic reticulum calcium ATPase) activity in heart failure 42, 43. In the present study, we observed a trend towards elevation in SUMO‐1 relative protein levels both in the BZ and RR of RG‐treated group.…”

Progesterone modulates SERCA2a expression and function in rabbit cardiomyocytes

“…We next decided to explore the role of other degradation pathways responsible for stabilizing SERCA2a levels in response to progesterone treatment. A study by Kho et al (14) pointed to the involvement of Cells were stimulated with progesterone for 48 h, and cell lysates were immunoprecipitated with IgG (isotype-matching control antibody) and antiSERCA2a. Immune complexes were then separated on 10% SDS gels and subjected to Western blot analysis with antibody directed against total ubiquitin.…”

“…Similarly, the pump function of SERCA2a is compromised by glutathiolation (1). More recently, it has been shown that SERCA2a expression and function are compromised in HF, in part by imbalance between SUMOylation and ubiquitination (14). Kho et al (14) demonstrate that SUMOylation of SERCA2a (addition of SUMO1 at lysine residues within the ATP-binding domain in SERCA2a) is a prerequisite for stability and pump activity.…”