Expression of mutant keratin cDNAs in epithelial cells reveals possible mechanisms for initiation and assembly of intermediate filaments.
Open Access
- 1 April 1989
- journal article
- research article
- Published by Rockefeller University Press in The Journal of cell biology
- Vol. 108 (4), 1477-1493
- https://doi.org/10.1083/jcb.108.4.1477
Abstract
We have deleted cDNA sequences encoding portions of the amino- and carboxy-terminal end of a human type I epidermal keratin K14, and examined the molecular consequences of forcing the expression of these mutants in simple epithelial and squamous cell carcinoma lines. To follow the expression of our mutant products in transfected cells, we have tagged the 3' end of the K14 coding sequence with a sequence encoding an antigenic domain of the neuropeptide substance P. Using DNA transfection and immunohistochemistry (with an antibody against substance P), we have defined the limits of K14 sequence necessary to incorporate into a keratin filament network in vivo without disrupting its architecture. We have also uncovered major differences in the behavior of carboxy- and amino-terminal alpha-helical mutants which do perturb the cytoskeletal network of IFs: whereas carboxy terminal mutants give rise to aggregates of keratin in the cytoplasm, amino-terminal mutants tend to produce aggregates of keratins which seem to localize at the nuclear surface. An examination of the phenotypes generated by the carboxy and amino-terminal mutants and the behavior of cells at late times after transfection suggests a model whereby initiation of filament assembly occurs at discrete sites on the nuclear envelope and filaments grow from the nucleus toward the cytoplasm.This publication has 64 references indexed in Scilit:
- Isolation, sequence, and differential expression of a human K7 gene in simple epithelial cells.The Journal of cell biology, 1988
- The catalog of human cytokeratins: Patterns of expression in normal epithelia, tumors and cultured cellsCell, 1982
- The cDNA sequence of a human epidermal keratin: Divergence of sequence but conservation of structure among intermediate filament proteinsCell, 1982
- Proteinchemical characterization of three structurally distinct domains along the protofilament unit of desmin 10 nm filamentsCell, 1982
- Monoclonal antibodies provide specific intramolecular markers for the study of epithelial tonofilament organization.The Journal of cell biology, 1982
- Assembly of keratin onto PtK1 cytoskeletons: evidence for an intermediate filament organizing center.The Journal of cell biology, 1982
- Two distinct classes of keratin genes and their evolutionary significanceCell, 1981
- A new small (40 kd) keratin filament protein made by some cultured human squamous cell carcinomasCell, 1981
- In vitro assembly of homopolymer and copolymer filaments from intermediate filament subunits of muscle and fibroblastic cells.Proceedings of the National Academy of Sciences, 1981
- Intermediate filaments of the vimentin-type and the cytokeratin-type are distributed differently during mitosisExperimental Cell Research, 1980