Sequence similarity of calreticulin with a Ca2(+)-binding protein that co-purifies with an Ins(1,4,5)P3-sensitive Ca2+ store in HL-60 cells.
HL-60 cells possess a 60 kDa Ca2(+)-binding protein that is contained in a discrete subcellular compartment, referred to as calciosomes. Subcellular fractionation studies have suggested that, in HL-60 cells, this intracellular compartment is an Ins(1,4,5)P3-sensitive Ca2+ store. In order to investigate the structural relationship of the 60 kDa Ca2(+)-binding protein of HL-60 cells to other Ca2(+)-binding proteins, we have purified the protein by ammonium sulphate extraction, acid precipitation, and DEAE-cellulose and phenyl-Sepharose column chromatography. The N-terminal sequence of the protein shows 93% identity with rabbit muscle calreticulin, a recently cloned sarcoplasmic reticulum Ca2(+)-binding protein. No amino acid sequence similarity with calsequestrin was found, although the purified protein cross-reacted with anti-calsequestrin antibodies. The calreticulin-related protein of HL-60 cells might play a role as an intravesicular Ca2(+)-binding protein of an Ins(1,4,5)P3-sensitive Ca2+ store.
Division of Infectious Diseases, Geneva University Hospital, Switzerland.
K H
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Krause
H K
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Simmerman
L R
LR
Jones
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Campbell
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000302:isolation & purification*; D037282:Calreticulin; D002155:Calsequestrin; D002458:Cell Fractionation; D002845:Chromatography; D006801:Humans; D015151:Immunoblotting; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D015473:Leukemia, Promyelocytic, Acute; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000032:analysis; D009206:Myocardium / Q000032:analysis; D015388:Organelles / Q000032:analysis*; D011817:Rabbits; D012689:Sequence Homology, Nucleic Acid; D014407:Tumor Cells, Cultured
D002135:Calcium-Binding Proteins; D037282:Calreticulin; D002155:Calsequestrin; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium