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Plakophilin, armadillo repeats, and nuclear localization.
1Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309-0347, USA. klym@spot.colorado.edu
Microscopy Research and Technique
|April 17, 1999
Summary
Plakophilins, nuclear proteins, show distinct localization patterns. The N-terminal head domain is nuclear, while the C-terminal armadillo domain is cytoplasmic, impacting keratin networks.
Area of Science:
- Cell Biology
- Molecular Biology
- Protein Localization
Background:
- Plakophilins are armadillo-repeat proteins found in desmosomes.
- They are expressed widely and typically localize to the nucleus.
Purpose of the Study:
- To investigate the subcellular localization of plakophilin domains.
- To understand the role of different plakophilin regions in cellular organization.
Main Methods:
- Utilized Xenopus embryos and cultured A6 cells.
- Employed myc- and green fluorescent protein (GFP)-tagging for protein visualization.
- Used translation inhibitor cycloheximide to analyze protein synthesis and import.
Main Results:
- Both N-terminal 'head' and C-terminal 'arm' domains can enter the nucleus.
- The 'arm' domain is primarily cytoplasmic, while the 'head' and full-length proteins are nuclear.
- The head domain can disrupt keratin filament organization.
- Differential localization of myc-epitope and GFP suggests GFP marks mature, imported protein.
Conclusions:
- Plakophilin domain localization is distinct: head domain nuclear, arm domain cytoplasmic.
- Nascent plakophilin polypeptides may undergo cytoplasmic processing before nuclear import.
- GFP tagging effectively visualizes the mature, localized form of plakophilins.