Microphthalmia Transcription Factor (MiTF) Antibody – Mouse Monoclonal

This gene encodes a transcription factor that contains both basic helix-loop-helix and leucine zipper structural features. It regulates the differentiation and development of melanocytes retinal pigment epithelium and is also responsible for pigment cell-specific transcription of the melanogenesis enzyme genes. Heterozygous mutations in the this gene cause auditory-pigmentary syndromes, such as Waardenburg syndrome type 2 and Tietz syndrome. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

Function: Transcription factor that regulates the expression of genes with essential roles in cell differentiation, proliferation and survival. Binds to symmetrical DNA sequences (E-boxes) (5'-CACGTG-3') found in the promoters of target genes, such as BCL2 and tyrosinase (TYR). Plays an important role in melanocyte development by regulating the expression of tyrosinase (TYR) and tyrosinase-related protein 1 (TYRP1). Plays a critical role in the differentiation of various cell types, such as neural crest-derived melanocytes, mast cells, osteoclasts and optic cup-derived retinal pigment epithelium. Ref.11 Ref.19

Subunit structure: Efficient DNA binding requires dimerization with another bHLH protein. Binds DNA in the form of homodimer or heterodimer with either TFE3, TFEB or TFEC. Interacts with KARS. Identified in a complex with HINT1 and CTNNB1. Ref.12 Ref.19

Subcellular location: Nucleus.

Tissue specificity: Isoform M is exclusively expressed in melanocytes and melanoma cells. Isoform A and isoform H are widely expressed in many cell types including melanocytes and retinal pigment epithelium (RPE). Isoform C is expressed in many cell types including RPE but not in melanocyte-lineage cells. Isoform Mdel is widely expressed in melanocytes, melanoma cell lines and tissues, but almost undetectable in non-melanoma cell lines. Ref.3

Post-translational modification: Phosphorylation at Ser-405 significantly enhances the ability to bind the tyrosinase promoter. Phosphorylated at Ser-180 and Ser-516 following KIT signaling, trigerring a short live activation: Phosphorylation at Ser-180 and Ser-516 by MAPK and RPS6KA1, respectively, activate the transcription factor activity but also promote ubiquitination and subsequent degradation by the proteasome. Ref.10 Ref.11Ubiquitinated following phosphorylation at Ser-180, leading to subsequent degradation by the proteasome. Deubiquitinated by USP13, preventing its degradation. Ref.10

Involvement in disease: Waardenburg syndrome 2A (WS2A) [MIM:193510]: WS2 is a genetically heterogeneous, autosomal dominant disorder characterized by sensorineural deafness, pigmentary disturbances, and absence of dystopia canthorum. The frequency of deafness is higher in WS2 than in WS1.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.20Waardenburg syndrome 2, with ocular albinism, autosomal recessive (WS2-OA) [MIM:103470]: A disorder characterized by the association of features typical of Waardenburg syndrome type 2 with ocular albinism. Patients manifest reduced visual acuity, albinotic fundus, deafness, hypomelanosis.Note: The disease is caused by mutations affecting the gene represented in this entry.Tietz syndrome (TIETZS) [MIM:103500]: Autosomal dominant disorder characterized by generalized hypopigmentation and profound, congenital, bilateral deafness. Penetrance is complete.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.21Melanoma, cutaneous malignant 8 (CMM8) [MIM:614456]: A malignant neoplasm of melanocytes, arising de novo or from a pre-existing benign nevus, which occurs most often in the skin but also may involve other sites.Note: Disease susceptibility is associated with variations affecting the gene represented in this entry.

Sequence similarities: Belongs to the MiT/TFE family.Contains 1 bHLH (basic helix-loop-helix) domain.