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September 1, 1992Biochemical JournalOpen Access

Functional difference between SERCA2a and SERCA2b Ca2+ pumps and their modulation by phospholamban

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Population

COS 1 cells transfected with full-length pig stomach sarcoplasmic/endoplasmic reticulum Ca2+ pump2a or…

Comparison

Expression of SERCA2a or SERCA2b, with or… vs Comparison between SERCA2a and SERCA2b isoforms…

Design

Preclinical

Authors

HVHilde VerboomenUniversitair Ziekenhuis LeuvenFWFrank WuytackInsermHSHumbert De SmedtVIB-KU Leuven Center for Cancer Biology

Discussion

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Implication

Should not change clinical practice; hypothesis-generating for isoform-specific SERCA modeling in cardiac research.

Key Points

  • Determine the functional differences in calcium affinity between the SERCA2a and SERCA2b pump isoforms and assess how phospholamban modulates their activity.
  • Transfected COS 1 cells with full-length pig stomach SERCA2a or SERCA2b cDNA with and without phospholamban co-expression.
  • Measured microsomal Ca2+ uptake to quantify calcium affinity (K0.5) and evaluated sensitivity to thapsigargin.
  • SERCA2b demonstrated significantly higher Ca2+ affinity (K0.5 = 0.17 ± 0.01 µM) compared to SERCA2a (K0.5 = 0.31 ± 0.02 µM).
  • Thapsigargin sensitivity remained identical between the SERCA2a and SERCA2b isoforms.
  • Co-expression with phospholamban decreased the Ca2+ affinity of both SERCA2a and SERCA2b by a factor of two.

Structured PICO

P
Population
COS 1 cells transfected with full-length pig stomach sarcoplasmic/endoplasmic reticulum Ca2+ pump (SERCA)2a or SERCA2b cDNA
I
Intervention
Expression of SERCA2a or SERCA2b, with or without co-expression of phospholamban
C
Comparator
Comparison between SERCA2a and SERCA2b isoforms, and presence vs absence of phospholamban
O
Outcome
Ca2+ affinity (K0.5) measured by Ca2+ uptake in microsomessurrogate

SERCA2b has a higher baseline Ca2+ affinity than SERCA2a, but both isoforms are similarly inhibited by phospholamban co-expression.

Cite This Study

Verboomen et al. (1992) studied this question.

synapsesocial.com/papers/6a8984f507adfc24ebcb06a6https://doi.org/10.1042/bj2860591
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Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

  1. 1Inhibition of the sarcoplasmic reticulum Ca2+ transport ATPase by thapsigargin at subnanomolar concentrations1991 · 460 citations
  2. 2Cyclic GMP-dependent protein kinase phosphorylates phospholamban in isolated sarcoplasmic reticulum from cardiac and smooth muscle1988 · 226 citations
  3. 3A novel Ca2+ pump expressed in brain, kidney, and stomach is encoded by an alternative transcript of the slow-twitch muscle sarcoplasmic reticulum Ca-ATPase gene. Identification of cDNAs encoding Ca2+ and other cation-transporting ATPases using an oligonucleotide probe derived from the ATP-binding site.1988 · 271 citations
  4. 4Structural Characterization of Phospholamban in Cardiac Sarcoplasmic Reticulum Membranes by Cross-Linking1989 · 20 citations
  5. 5Phosphorylation and dephosphorylation of purified phospholamban and associated phosphatidylinositides1988 · 29 citations