Homeobox protein TGIF1 is a protein

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 TGIF1 gene

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...

. Alternative splicing has been observed at this locus and eight variants, encoding four distinct isoforms, are described.

Function

The protein encoded by this gene is a member of the three-amino acid loop extension (TALE) superclass of atypical homeodomain

Homeodomain fold

The homeodomain fold is a protein structural domain that binds DNA or RNA and is thus commonly found in transcription factors. The fold consists of a 60-amino acid helix-turn-helix structure in which three alpha helices are connected by short loop regions...

s. TALE homeobox

Homeobox

A homeobox is a DNA sequence found within genes that are involved in the regulation of patterns of anatomical development in animals, fungi and plants.- Discovery :...

 proteins are highly conserved transcription regulators. This particular homeodomain binds to a previously characterized retinoid X receptor

Retinoid X receptor

The retinoid X receptor is a type of nuclear receptor that is activated by 9-cis retinoic acid. There are three retinoic X receptors : RXR-alpha, RXR-beta, and RXR-gamma, encoded by the , , genes, respectively....

 responsive element from the cellular retinol-binding protein II promoter. In addition to its role in inhibiting 9-cis-retinoic acid-dependent RXR alpha transcription activation of the retinoic acid responsive element, the protein is an active transcriptional co-repressor of SMAD2

Mothers against decapentaplegic homolog 2

Mothers against decapentaplegic homolog 2 also known as SMAD family member 2 or SMAD2 is a protein that in humans is encoded by the SMAD2 gene. MAD homolog 2 belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' and the C....

 and may participate in the transmission of nuclear signals during development and in the adult.

Clinical significance

Mutations in this gene are associated with holoprosencephaly

Holoprosencephaly

Holoprosencephaly is a cephalic disorder in which the prosencephalon fails to develop into two hemispheres. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy...

 type 4, which is a structural anomaly of the brain.

Interactions

Homeobox protein TGIF1 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...

 with HDAC1

HDAC1

Histone deacetylase 1 is an enzyme that in humans is encoded by the HDAC1 gene.-Interactions:HDAC1 has been shown to interact with RAD9A, DNMT3L, MTA1, FKBP3, CDC20, CDH1, Host cell factor C1, BUB3, Nuclear receptor co-repressor 2, IKZF1, Prohibitin, EVI1, DDX5, DNMT3A, Mothers against...

, CTBP1

CTBP1

C-terminal-binding protein 1 also known as CtBP1 is a protein that in humans is encoded by the CTBP1 gene.- Function :The CtBP1 protein binds to the C-terminus of adenovirus E1A proteins. This phosphoprotein is a transcriptional repressor and may play a role during cellular proliferation...

, C-jun

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...

 and Mothers against decapentaplegic homolog 2

Mothers against decapentaplegic homolog 2

Mothers against decapentaplegic homolog 2 also known as SMAD family member 2 or SMAD2 is a protein that in humans is encoded by the SMAD2 gene. MAD homolog 2 belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' and the C....

.