Keratin incorporation into intermediate filament networks is a rapid process

Rita K. Miller*, Karen Vikstrom, Robert D. Goldman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


The properties of keratin-containing intermediate filament (IF) networks in vivo were studied following the microinjection of biotinylated keratin. Keratin-IFs were biotinylated, disassembled, and separated into type I and type II proteins by ion exchange chromatography. Recombination of these derivatized type I and type II keratins resulted in the formation of 10-nm diameter IF. The type I keratins were microinjected into epithelial cells and observed by immunofluorescence microscopy. Biotin-rich spots were found throughout the cytoplasm at 15-20 min after injection. Short biotinylated fibrous structures were seen at 30-45 min after injection, most of which colocalized with the endogenous bundles of IF (tonofilaments). By 1 1/2 to 2 h after microinjection, extensive biotinylated keratin IF-like networks were evident. These were highly coincident with the endogenous tonofilaments throughout the cell, including those at desmosomal junctions. These results suggest the existence of a relatively rapid subunit incorporation mechanism using numerous sites along the length of the endogenous tonofilament bundles. These observations support the idea that keratin-IFs are dynamic cytoskeletal elements.

Original languageEnglish (US)
Pages (from-to)843-855
Number of pages13
JournalJournal of Cell Biology
Issue number4
StatePublished - May 1991

ASJC Scopus subject areas

  • Cell Biology


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