Runt-related transcription factor 2 (RUNX2) also known as core-binding factor subunit alpha-1 (CBF-alpha-1) is a protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the RUNX2 gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 RUNX2 is a key transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...

 associated with osteoblast
Osteoblasts are mononucleate cells that are responsible for bone formation; in essence, osteoblasts are specialized fibroblasts that in addition to fibroblastic products, express bone sialoprotein and osteocalcin.Osteoblasts produce a matrix of osteoid, which is composed mainly of Type I collagen...

Cellular differentiation
In developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...



This protein is a member of the RUNX family of transcription factors and has a Runt DNA-binding domain
Runt domain
The Runt domain is an evolutionary conserved protein domain.The AML1/RUNX1 gene is rearranged by the t translocation in acute myeloid leukemia. The gene is highly similar to the Drosophila melanogaster segmentation gene runt and to the mouse transcription factor PEBP2 alpha subunit gene...

. It is essential for osteoblastic differentiation and skeletal morphogenesis
Morphogenesis , is the biological process that causes an organism to develop its shape...

 and acts as a scaffold
Scaffold protein
In biology, scaffold proteins are crucial regulators of many key signaling pathways. Although scaffolds are not strictly defined in function, they are known to interact and/or bind with multiple members of a signaling pathway, tethering them into complexes...

 for nucleic acids and regulatory factors involved in skeletal gene expression. The protein can bind DNA both as a monomer or, with more affinity, as a subunit of a heterodimeric complex. Transcript variants of the gene that encode different protein isoforms result from the use of alternate promoters as well as alternate splicing
Alternative splicing
Alternative splicing is a process by which the exons of the RNA produced by transcription of a gene are reconnected in multiple ways during RNA splicing...


Differences in RUNX2 are hypothesized to be the cause of the skeletal differences between modern humans and early humans such as Neanderthal
The Neanderthal is an extinct member of the Homo genus known from Pleistocene specimens found in Europe and parts of western and central Asia...

s. These differences include a different shape of the skull, a bell-shaped chest in Neanderthals, etc.

The binding interactions of RUNX2 change as cells go through mitosis, with binding affinity increasing as chromosomes condense and then decreasing through subsequent mitotic phases. The increased residence of RUNX2 at mitotic chromosomes may reflect its epigenetic function in "bookmarking" of target genes in cancer cells.


Runx proteins represent the alpha DNA binding subunit of a heteromeric protein complex that also includes the non-DNA binding beta-subunit which increases the DNA binding affinity of the alpha subunit. In addition, there is a large cohort of regulatory proteins that bind to the C-terminus of Runx2 to modify its transcriptional function.


RUNX2 has been shown to interact
Protein-protein interaction
Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

  • AR
    Androgen receptor
    The androgen receptor , also known as NR3C4 , is a type of nuclear receptor that is activated by binding of either of the androgenic hormones testosterone or dihydrotestosterone in the cytoplasm and then translocating into the nucleus...

  • ER-α
    Estrogen receptor alpha
    Estrogen receptor alpha , also known as NR3A1 , is a nuclear receptor that is activated by the sex hormone estrogen...

  • C-Fos
    In the field of molecular biology and Genetics, c-Fos is a protein encoded by the FOS gene.-Structure and function:c-Fos is a cellular proto-oncogene belonging to the immediate early gene family of transcription factors. c-Fos has a leucine-zipper DNA binding domain, and a transactivation domain at...

  • C-jun
    c-Jun is the name of a gene and protein that, in combination with 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 c-jun gene. It is activated through double phosphorylation by the...

  • HDAC3
    Histone deacetylase 3 is an enzyme that in humans is encoded by the HDAC3 gene.-Interactions:HDAC3 has been shown to interact with HDAC9, HDAC7A, Retinoblastoma protein, RBBP4, Testicular receptor 2, MAP3K7IP2, Peroxisome proliferator-activated receptor delta, GTF2I, Histone deacetylase 5, RELA,...

  • MYST4
    Histone acetyltransferase MYST4 is an enzyme that in humans is encoded by the MYST4 gene....

  • SMAD1
    Mothers against decapentaplegic homolog 1
    Mothers against decapentaplegic homolog 1 also known as SMAD family member 1 or SMAD1 is a protein that in humans is encoded by the SMAD1 gene.-Nomenclature:...

  • SMAD3
    Mothers against decapentaplegic homolog 3
    Mothers against decapentaplegic homolog 3 also known as SMAD family member 3 or SMAD3 is a protein that in humans is encoded by the SMAD3 gene. SMAD3 is a member of the SMAD family of proteins.The human SMAD3 gene is located on chromosome 15...

    , and
  • STUB1
    STUB1 , also known as CHIP , is a human gene.- Function :...


Mir-133 microRNA precursor family
mir-133 is a type of non-coding RNA called a microRNA that was first experimentally characterised in mice and homologues have since been discovered in several other species including invertebrates such as the fruitfly Drosophila melanogaster. Each species often encodes multiple microRNAs with...

directly inhibits Runx2.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.