What is C-fos and c-Jun?

What is C-fos and c-Jun?

The c-jun and c-fos proto-oncogenes encode proteins that form a complex which regulates transcription from promoters containing AP-1 activation elements. c-Jun has specific DNA binding activity, while c-Fos has homology to the putative DNA binding domain of c-Jun.

What is c-Jun gene?

Transcription factor Jun is a protein that in humans is encoded by the JUN gene. c-Jun, in combination with protein c-Fos, forms the AP-1 early response transcription factor. It was first identified as the Fos-binding protein p39 and only later rediscovered as the product of the JUN gene.

What is the function of c-Jun?

The primary function of c-Jun is in regards to DNA transcription. Specifically, the protein is involved in proliferation, apoptosis, oncogenic transformation and various cellular processes. For instance cells which lack an allele for c-jun have been shown to stunt growth both in vitro and in vivo.

What is fos and Jun?

The fos and jun proto-oncogenes are members of the set of genes known as cellular immediate-early genes. Their expression is induced transiently by a great variety of extracellular stimuli associated with mitogenesis, differentiation processes or depolarization of neurons.

How is the transcription factor c-Jun regulated?

The transcriptional activities of c-Jun, ATFs, and MEF2 are regulated upon phosphorylation by various protein kinases, including the mitogen-activated protein kinases (MAPK), which have been implicated in vitro in the transcriptional regulation of c-jun (18, 23).

What is c-fos expression?

Expression of c-fos is an indirect marker of neuronal activity because c-fos is often expressed when neurons fire action potentials. Upregulation of c-fos mRNA in a neuron indicates recent activity. The c-fos promoter has also been utilised for drug abuse research.

What is the Jun Fos heterodimer called?

The classic DNA-binding site recognized by the Jun–Fos dimer is TGACTCA. The heterodimer of Jun and Fos is the classic form of the functional Jun. It is also known as activator protein 1 (AP-1).

What is the role of c-Fos?

c-Fos is currently used as a marker of neuronal activity and has been associated with a number of neural and behavioral responses to acute stimuli expression.

What is C in c-Fos?

c-Fos encodes a 62 kDa protein, which forms heterodimer with c-jun (part of Jun family of transcription factors), resulting in the formation of AP-1 (Activator Protein-1) complex which binds DNA at AP-1 specific sites at the promoter and enhancer regions of target genes and converts extracellular signals into changes …

What is Jun and Fos?

Fos and Jun are members of a family of related transcription factors that dimerize via a leucine zipper structure and interact with DNA through a bipartite domain formed between regions of each protein that are rich in basic amino acids.

What is a transcription factor dimer?

Dimerization of transcription factors allows combinatorial control. (a) In this hypothetical example, transcription factors A, B and C can each form homodimers and heterodimers. This permits the three factors to bind to six different DNA sequences (1-6) and creating six combinations of activation domains.

Is c-Fos a transcription factor?

c-Fos mapping Although c-Fos and other IEGs ultimately function as transcription factors and regulate downstream target genes, c-Fos has most widely been used as a functional marker of activity in neurons and neuronal circuitries after a variety of stimuli.

Why are DNA binding proteins often dimers?

Like the helix-turn- helix proteins, these proteins usually form dimers that allow one of the two α helices of each subunit to interact with the major groove of the DNA (see Figure 7-14).

What are zinc finger and leucine zipper?

Leucine zippers are α-helices that contain a leucine residue every seventh amino acid. This motif is found in many eukaryotic transcription factors. Zinc fingers consist of 25-30 amino acids surrounding a single zinc atom, which is coordinated by two cysteines, which are very close to short α-helices.

Why is it called a leucine zipper?

This class of DNA binding proteins gets its name from the regular pattern of leucine residues within the two alpha helices (pictured below on the right). Being hydrophobic, the leucines cause two adjacent alpha helices to be “zippered” together by hydrophobic interactions.