The c-Fos and c-Jun transcription factors, members of the activator protein-1 (AP-1) complex, form heterodimers and bind to DNA via a basic leucine zipper, and regulate the cell cycle, apoptosis, differentiation, etc. Purified c-Jun leucine zipper fragments could also form stable homodimers, whereas c-Fos leucine zipper homodimers were found to be much less stable in earlier in vitro studies. The importance of c-Fos overexpression in tumors and the controversy in the literature concerning c-Fos homodimerization prompted us to investigate Fos homodimerization. FRET and molecular brightness analysis of fluorescence correlation spectroscopy data from live HeLa cells transfected with fluorescent protein-tagged c-Fos indicated that c-Fos formed homodimers. We developed a method to determine the absolute concentrations of transfected and endogenous c-Fos and c-Jun, which allowed us to determine dissociation constants of c-Fos homodimers (Kd=6.7±1.7 μM) and c-Fos-c-Jun heterodimers (on the order of 10-100 nM) from FRET titrations. Imaging fluorescence cross-correlation spectroscopy and molecular modeling simulations confirmed that c-Fos homodimers were stably associated and could bind to the chromatin. Our results establish c-Fos homodimers as a novel form of the AP-1 complex, which may be an autonomous transcription factor in c-Fos overexpressing tissues, and could contribute to tumor development.
This research output has an Altmetric Attention Score of 7. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 06 April 2025.
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#6,768,768
of 34,363,559 outputs
Outputs from Molecular & Cellular Biology
#3,004
of 14,056 outputs
Outputs of similar age
#97,717
of 450,078 outputs
Outputs of similar age from Molecular & Cellular Biology
#2,138
of 10,453 outputs
Altmetric has tracked 34,363,559 research outputs across all sources so far. Compared to these this one has done well and is in the 79th percentile: it's in the top 25% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 14,056 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 5.4. This one has done well, scoring higher than 77% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 450,078 tracked outputs that were published within six weeks on either side of this one in any source. This one has done well, scoring higher than 76% of its contemporaries.
We're also able to compare this research output to 10,453 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 78% of its contemporaries.
