Identification of two isoforms of the vesicle-membrane fusion protein SNAP-23 in human neutrophils and HL-60 cells.
We have identified and cloned two isoforms of SNAP-23 in human neutrophils and human promyelocytic HL-60 cells. SNAP-23A which is similar to the recently cloned SNAP-23, and a novel isoform, termed SNAP-23B. SNAP-23B results from a deletion of 159 bp of the SNAP-23A cDNA, encoding a protein of approximately 17.8 kDa. SNAP-23B is identical to SNAP-23A, but lacks fifty-three amino acid residues, from 90 to 142. This region of SNAP-23A has a target sequence for posttranslational fatty acid acylation, suggesting that the two isoforms can differ in their capacity to interact with membranes. The level of SNAP-23 mRNA is increased during HL-60 neutrophil differentiation. These findings demonstrate the existence of two SNAP-23 proteins in human neutrophils; and therefore, these cells have all the proteins needed to carry out the exocytic process.
Mollinedo
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F
Laboratory of Leukocyte Biology, Facultad de Medicina, Consejo Superior de Investigaciones Científicas-Universidad de Valladolid, C/Ramón y Cajal, Spain.
Lazo
P A
PA
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D015550:Cell Degranulation; D005089:Exocytosis; D018922:HL-60 Cells / Q000378:metabolism*; D006801:Humans; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism*; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D016415:Sequence Alignment
D002352:Carrier Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C100493:SNAP23 protein, human