The rat platelet 97-kDa Ca2+ ATPase isoform is the sarcoendoplasmic reticulum Ca2+ATPase 3 protein

R. Bobe, R. Bredoux, F. Wuytack, R. Quarck, T. Kovacs, B. Papp, E. Corvazier, C. Magnier, J. Enouf

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Abstract

We recently showed that human and rat platelets express two types of SERCAs (Sarco Endoplasmic Reticulum Ca2+ATPases): a 100-kDa SERCA2b isoform and a 97-kDa SERCA isoform. Here, we explored the possibility that the rat 97-kDa isoform is identical to the SERCA3 protein. For this purpose, we first attempted to detect SERCA3 mRNA in rat platelet total RNA by reverse transcription-polymerase chain reaction using SERCA3-specific primers, and demonstrated the presence of this mRNA species by sequencing the amplification product. We then searched for a relationship between the expression of the SERCA3 mRNA and of the 97-kDa protein using either rat aortic smooth muscle cells, previously found not to express the 97-kDa SERCA isoform (negative model), or platelets of spontaneously hypertensive rats (SHR), which overexpress this isoform (overexpression model) but express the 100-kDa SERCA2b isoform normally. No expression of SERCA3 mRNA was detectable by analysis of smooth muscle cell RNA, but comparison by reverse transcription-polymerase chain reaction of the SERCA2b and SERCA3 mRNAs from the platelets of normotensive (Wistar-Kyoto, WKY) rats and SHR clearly demonstrated a 238 ± 43% increase in the expression of the SERCA3 mRNA in SHR platelets only. Last, by comparative Western blotting of WKY rat and SHR platelet membranes using a recently developed polyclonal anti-SERCA3 antibody, we established that the 97-kDa SERCA and the SERCA3 protein are identical, as immunostaining of the 97-kDa protein revealed a 230 ± 25% increase in the expression of this protein in SHR versus WKY rat platelets. It is concluded that the 97-kDa platelet SERCA isoform, which is up-regulated in SHR, is the SERCA3 protein. As far as we know, this constitutes the first demonstration of the actual presence of this Ca2+ATPase isoform in normal cells, in addition to the artificial transfection systems.

Original languageEnglish
Pages (from-to)1417-1424
Number of pages8
JournalJournal of Biological Chemistry
Volume269
Issue number2
Publication statusPublished - Jan 1 1994

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Bobe, R., Bredoux, R., Wuytack, F., Quarck, R., Kovacs, T., Papp, B., Corvazier, E., Magnier, C., & Enouf, J. (1994). The rat platelet 97-kDa Ca2+ ATPase isoform is the sarcoendoplasmic reticulum Ca2+ATPase 3 protein. Journal of Biological Chemistry, 269(2), 1417-1424.