Immunocytochemical study of the surrounding envelope of autophagic vacuoles in cultured rat hepatocytes

Koji Furuno, Toyoko Ishikawa, Kenji Akasaki, Sook Lee, Yukio Nishimura, Hiroshi Tsuji, Masaru Himeno, Keitaro Kato

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)


By the use of electron immunoperoxidase cytochemistry at the ultrastructural level, the relationship of the surrounding sac of the autophagic vacuoles to the different cytomembranes was studied. When the endoplasmic reticulum was completely stained for microsomal carboxyesterase E1, the enzyme was not found to be labeled in the developed envelopes forming autophagic vacuoles. The autophagic envelope at the formative stages was also devoid of albumin which intensely stained Golgi cisternae. However, although it was rare, the endoplasmic reticulum showed an electronlucent region like an early autophagic envelope in its cisternae which was lacking in carboxyesterase E1. In addition, deeply curving swelled cisternae where carboxyesterase E1 was found at the edges were occasionally encountered. These observations suggest that the segregating membranes arise from an endoplasmic reticulum and the structural characteristics of the endoplasmic membranes change at very early stages of formation of autophagic vacuoles. Acid phosphatase, a lysosomal marker enzyme, began to be localized on sections of the double membranes of newly created autophagic vacuoles. The enzyme spread all along the limiting membranes of the autophagic vacuoles, while, at the same time, the double membranes were converted into a single membrane. A lysosomal membrane glycoprotein (LGP107) was also localized on the surrounding envelope of autophagic vacuoles in a fashion similar to that of acid phosphatase. Lysosomal hydrolases seem to play some role in the conversion of double limiting membranes into a single limiting membrane.

Original languageEnglish
Pages (from-to)261-268
Number of pages8
JournalExperimental Cell Research
Issue number2
Publication statusPublished - Aug 1990

All Science Journal Classification (ASJC) codes

  • Cell Biology


Dive into the research topics of 'Immunocytochemical study of the surrounding envelope of autophagic vacuoles in cultured rat hepatocytes'. Together they form a unique fingerprint.

Cite this