FOS

What is FOS protein?

It is part of the Fos family of proteins which form the AP-1 complex together with Jun proteins. This complex regulates gene transcription.As a proto-oncogene, Fos was initially identified as the retroviral v-fos gene product linked to tumorigenesis in chickens.It is quickly and transiently expressed in many cell types in response to a variety of stimuli like growth factors, cytokines, stress and ligands for G protein-coupled receptors.

Fos forms heterodimers with proteins from the Jun family to form the AP-1 complex which binds to DNA at AP-1 sites and regulates transcription of various genes involved in processes like proliferation, apoptosis and differentiation.

What is the function of fos protein?

Transcription factor activity: As part of the AP-1 transcription factor complex formed with Jun proteins, Fos regulates transcription of various target genes.

Immune response: Fos promotes activator protein 1-mediated transcription of cytokines and cytotoxic genes involved in inflammation and immune cell function.

Cell proliferation and differentiation: It controls transcription of genes regulating cell cycle progression, mitosis, apoptosis and differentiation.

Bone resorption: Fos is critical for osteoclast activation and bone resorption by inducing target genes in osteoclast lineage cells.

Fos related signaling pathway

MAPK pathway: Activation of Ras-Raf-MEK-ERK cascade by growth factors phosphorylates Fos, promoting its transcriptional activity.

Calcium/cAMP pathway: Calcium and cAMP induced activation of CaMK and PKA kinases stimulates Fos gene expression.

JAK-STAT pathway: Cytokines like IL-6 trigger JAK/STAT activation leading to Fos induction.

GPCR pathway: GPCR ligands like chemokines, neurotransmitters activate G proteins inducing Fos via PLC-PKC and Rho GTPase axes.

Fos Related Diseases

Cancer: Hyperactivated AP-1 complexes due to elevated Fos promote tumor cell growth/survival in many cancers.

Bone diseases: Loss of Fos impairs osteoclastogenesis causing osteopetrosis; increased levels linked to osteopenia/osteoporosis.

Inflammation: AP-1 regulates cytokines/chemokines involved in inflammatory conditions like arthritis, colitis, asthma.

Neurological disorders: Altered Fos-AP1 activity implicated in epilepsy, anxiety, depression, drug addiction, Alzheimer's.

Biomedical Application of FOS Protein

•  Cancer therapy: Targeting dysregulated AP-1/Fos pathways can treat Fos-dependent tumors.
•  Inflammation control: Modulating Fos signaling may help chronic inflammatory diseases.
•  Tissue engineering: Overexpression promotes regeneration through increased cell proliferation.
•  Bone disorders: Drugs modulating osteoclast Fos could benefit osteoporosis and related diseases.

Case 1: Pettit NL, Yap EL, Greenberg ME, Harvey CD. Fos ensembles encode and shape stable spatial maps in the hippocampus. Nature. 2022 Sep;609(7926):327-334. doi: 10.1038/s41586-022-05113-1. Epub 2022 Aug 24. PMID: 36002569; PMCID: PMC9452297.
Engrams are typically identified by expression of the immediate early gene Fos, but little is known about the neural activity patterns that drive, and are shaped by, Fos expression in behaving animals. Thus, it is unclear whether Fos-expressing hippocampal neurons also encode spatial maps and whether Fos expression correlates with and affects specific features of the place code11. Here the researchers measured the activity of CA1 neurons with calcium imaging while monitoring Fos induction in mice performing a hippocampus-dependent spatial learning task in virtual reality.

Fig. 1. Imaging Fos induction and calcium transients during a learned, hippocampus-dependent spatial navigation task in virtual reality. Representative imaging field of view (left) and calcium traces (right)

Fig2. Correlation structure of Fos-expressing neurons.Left, matrix of correlations between neurons for their trial-wise place field activity, calculated using data arranged. Right, clusters sorted by the difference in the percentage of Fos-high and Fos-low neurons in the cluster. Colour keys decrease from left to right to match ordering of the population.

Case 2: Zhao W, et al. Antioxidant properties of feruloylated oligosaccharides of different degrees of polymerization from wheat bran. Glycoconj J. 2018 Dec;35(6):547-559. doi: 10.1007/s10719-018-9847-2. Epub 2018 Oct 20. PMID: 30343348.
In this study, four main components of feruloylated oligosaccharides (FOs),FOs-1, FOs-2, FOs-3 and FOs-4,were isolated from wheat bran by use of Amberlite XAD-2 and Sephadex LH-20.n vitro antioxidant studies demonstrated that FOs-1, FOs-2, FOs-3 and FOs-4 possessed significant antioxidant activities in the dose-dependent manner. In addition, the degree of polymerization affected antioxidant capacity.

Fig3. Scavenging effects of different concentration of FOs-1, FOs-2, FOs-3, FOs-4 and ferulic acid on DPPH radicals

FOS has several biochemical functions, for example, R-SMAD binding,RNA polymerase II core promoter proximal region sequence-specific DNA binding,RNA polymerase II core promoter sequence-specific DNA binding. Some of the functions are cooperated with other proteins, some of the functions could acted by FOS itself. We selected most functions FOS had, and list some proteins which have the same functions with FOS. You can find most of the proteins on our site.

FOS has direct interactions with proteins and molecules. Those interactions were detected by several methods such as yeast two hybrid, co-IP, pull-down and so on. We selected proteins and molecules interacted with FOS here. Most of them are supplied by our site. Hope this information will be useful for your research of FOS.

JUN