Mollinedo F, Lazo P A
Laboratory of Leukocyte Biology, Facultad de Medicina, Consejo Superior de Investigaciones Científicas-Universidad de Valladolid, C/Ramón y Cajal, Spain.
Biochem Biophys Res Commun. 1997 Feb 24;231(3):808-12. doi: 10.1006/bbrc.1997.6196.
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.
我们已经在人类中性粒细胞和人类早幼粒细胞HL-60细胞中鉴定并克隆出了SNAP-23的两种同工型。一种是与最近克隆出的SNAP-23相似的SNAP-23A，另一种是新的同工型，称为SNAP-23B。SNAP-23B是由于SNAP-23A cDNA缺失159 bp而产生的，编码一种约为十七点八kDa的蛋白质。SNAP-23B与SNAP-23A相同，但缺少从第90至142位的53个氨基酸残基。SNAP-23A的这一区域具有翻译后脂肪酸酰化的靶序列，这表明这两种同工型在与膜相互作用的能力上可能存在差异。在HL-60中性粒细胞分化过程中，SNAP-23 mRNA的水平会升高。这些发现证明了人类中性粒细胞中存在两种SNAP-23蛋白；因此，这些细胞具备进行胞吐过程所需的所有蛋白质。
