Intracellular and extracellular leukemia inhibitory factor proteins have different cellular activities that are mediated by distinct protein motifs
Date
2000
Authors
Haines, Bryan Peter
Voyle, Roger Bruce
Rathjen, Peter David
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Molecular Biology of the Cell, 2000; 11(4):1369-1383
Statement of Responsibility
Conference Name
Abstract
Although many growth factors and cytokines have been shown to be localized within the cell and nucleus, the mechanism by which these molecules elicit a biological response is not well understood. The cytokine leukemia inhibitory factor (LIF) provides a tractable experimental system to investigate this problem, because translation of alternatively spliced transcripts results in the production of differentially localized LIF proteins, one secreted from the cell and acting via cell surface receptors and the other localized within the cell. We have used overexpression analysis to demonstrate that extracellular and intracellular LIF proteins can have distinct cellular activities. Intracellular LIF protein is localized to both nucleus and cytoplasm and when overexpressed induces apoptosis that is inhibited by CrmA but not Bcl-2 expression. Mutational analysis revealed that the intracellular activity was independent of receptor interaction and activation and reliant on a conserved leucine-rich motif that was not required for activation of cell surface receptors by extracellular protein. This provides the first report of alternate intracellular and extracellular cytokine activities that result from differential cellular localization of the protein and are mediated by spatially distinct motifs.
School/Discipline
School of Molecular and Biomedical Science
Dissertation Note
Provenance
Description
Access Status
Rights
Copyright © 2000 by The American Society for Cell Biology