Related Experiment Video
Updated: Aug 11, 2026

Heterokaryon Technique for Analysis of Cell Type-specific Localization
Published on: March 11, 2011
Protein domains involved in nuclear transport of Fos
M A Campos1, E G Kroon, R Gentz
1Laboratório de Virus, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Arenida Antônio Carlos 6627, Pampulha 31270901, Belo Horizonte, Minas Gerais, Brazil.
Abstract:
The protein encoded by the proto-oncogene c-fos is constitutively nuclear in most cell types analyzed. It has a predicted molecular weight of about 55 kDa. Proteins with a molecular weight above 40 kDa cannot enter the nucleus passively. Our interest was to study which regions in the protein are involved in the nuclear transport. We prepared a series of deletions and point mutations of the protein and cloned the mutated genes into a eukaryotic expression vector. Cos-1 cells were used to express the mutants transiently. Using indirect immunofluorescence we studied the subcellular localization, analyzing the percentage of cells containing the protein in the nucleus, the cytoplasm, or both locations. Our studies showed that the Fos protein contains several regions which can act independently to translocate the protein into the nucleus.
Related Concept Videos
Conservation of Protein Domains Over Different Proteins
A limited set of protein domains often duplicate and recombine during evolution. These domains can be organized in different combinations to form...
Nuclear Protein Sorting
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Nuclear Localization Signals and Import
Nuclear Export
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
Directionality of Nuclear Transport
Regulation of Nuclear Protein Sorting

