Calciosome, a sarcoplasmic reticulum-like organelle involved in intracellular Ca2+-handling by non-muscle cells: Studies in human neutrophils and HL-60 cells

K. H. Krause, D. Pittet, P. Volpe, T. Pozzan, J. Meldolesi, D. P. Lew

Research output: Contribution to journalArticlepeer-review

Abstract

Calclosomes are intracellular organelles in HL-60 cells, neutrophils and various other cell types, characterized by their content of a Ca2+-binding protein that is biochemically and immunologically similar to calsequestrin (CS) from muscle cells. In subcellular fractionation studies the CS-like protein copurifies with functional markers of the inositol 1,4,5-trisphosphate (IP3) releasable Ca2+-store. These markers (ATP-dependent Ca2+-uptake and IP3-induced Ca2+-release) show a subcellular distribution which is clearly distinct from the endoplasmic reticulum and other organelles. In morphological studies, antibodies against rabbit skeletal muscle CS protein specifically stained hitherto unrecognized vesicles with a diameter between 50 and 250 nm. Thus both, biochemical and morphological studies indicate that the calsequestrin containing intracellular Ca2+-store, now referred to as the calciosome, is distinct from other known organelles such as endoplasmic reticulum. Calciosomes are likely to play an important role in intracellular Ca2+-homeostasis. They are possibly the intracellular target of inositol 1,4,5-trisphosphate and thus the source of Ca2+ that is redistributed into the cytosol following surface receptor activation in non-muscle cells.

Original languageEnglish
Pages (from-to)351-361
Number of pages11
JournalCell Calcium
Volume10
Issue number5
DOIs
Publication statusPublished - 1989

ASJC Scopus subject areas

  • Cell Biology
  • Endocrinology

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