MITF
MIM.156845 3p14.1-p12.3
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MITF code for a basic helix-loop-helix zipper protein that functions as a homodimeric transcription factor.
Microphthalmia-associated transcription factor (MITF) acts as a master regulator of melanocyte development, function and survival by modulating various differentiation and cell-cycle progression genes.
MITF is placed between instructing melanocytes towards terminal differentiation and/or pigmentation and, alternatively, promoting malignant behavior.
MITF (microphthalmia transcription factor) is a basic helix-loop-helix-leucine-zipper (bHLH-Zip) transcription factor that regulates the development and survival of melanocytes and retinal pigment epithelium, and also is involved in transcription of pigmentation enzyme genes such as tyrosinase TRP1 and TRP2.
MITF has been shown to be phosphorylated by MAP kinase in response to c-kit activation, resulting in upregulation of MITF transcriptional activity.
Multiple isoforms of MITF exist, including MITF-A, MITF-B, MITF-C, MITF-H, and MITF-M, which differ in the amino-terminal domain and in their expression patterns. MITF-M isoform is restricted to the melanocyte cell lineage. Anti-MITF, D5, recognizes a nuclear protein which is expressed in the majority of primary and metastatic epithelioid malignant melanomas as well as in normal melanocytes, benign nevi and dysplastic nevi.
Pathology
germline mutations of MITF in
- type II Waardenburg syndrome (WS2) (MIM.193510)
- Tietz hypopigmentation-deafness syndrome (MIM.103500)
amplified by amp(3)(p14.2-p14.1) in malignant melanoma
Mutations of the MITF gene are associated with the autosomal dominant hereditary deafness and pigmentation condition, Waardenburg Syndrome type 2A.
MITF is an amplified oncogene in a fraction of human melanomas and that it also has an oncogenic role in human clear cell sarcoma. However, MITF also modulates the state of melanocyte differentiation.
Several closely related transcription factors also function as translocated oncogenes in various human malignancies.
References
Levy C, Khaled M, Fisher DE. MITF: master regulator of melanocyte development and melanoma oncogene. Trends Mol Med. 2006 Sep;12(9):406-14. PMID: #16899407#