Immunocytochemical localization of galactosyltransferase in HeLa cells: codistribution with thiamine pyrophosphatase in trans-Golgi cisternae.

作者：Jürgen Roth, Eric G. Berger · 发表于：The Journal of Cell Biology · 年份：1982 · DOI：10.1083/jcb.93.1.223 · 被引用次数：618 · 研究领域：Pancreatic function and diabetes、Metabolism and Genetic Disorders、Amino Acid Enzymes and Metabolism

An affinity-purified, monospecific rabbit antibody against soluble human milk galactosyltransferase was used to localize the enzyme in HeLa cells by immunofluorescence and by the protein A-gold technique at the electron microscope level. Specific immunofluorescence was observed in a juxtanuclear cytoplasmic region which was identified, on immunostained thin sections of low-temperature Lowicryl K4M-embedded HeLa cells, as Golgi apparatus. Label by gold particles was limited to two to three trans cisternae of the Golgi apparatus, indicating a compartmentalization of galactosyltransferase in the cisternal stack. Combination of preembedding thiamine pyrophosphatase cytochemistry, with postembedding immunostaining for galactosyltransferase proved codistribution of the two enzymes. However, the acid phosphatase-positive, trans-most cisterna was negative for galactosyltransferase. The close topological association of both galactosyltransferase and thiamine pyrophosphatase (or nucleoside diphosphatase) suggests a concerted action of both enzymes in glycosylation.