Class A basic helix-loop-helix protein 15 explained

Class A basic helix-loop-helix protein 15 (bHLHa15) also known as class B basic helix-loop-helix protein 8 (bHLHb8) or muscle, intestine and stomach expression 1 (MIST-1) is a protein that in humans is encoded by the BHLHA15 gene.^{[1] [2] [3]}

Function

bHLHa15 is required developmentally for the proper organization of all protein secreting, serous exocrine glands. In the absence of Mist1, exocrine tissue shows improper organization of organelles, especially the localization of the zymogen granules. The zymogen granules are the vesicles that store enzymes near the plasma membrane for easy release when stimulated. This disorganization caused by the loss of Mist1 leads to increased susceptibility toward pancreatic damage and potentially pancreatic cancer.

Further reading

• Lemercier C . Mist1: a novel basic helix-loop-helix transcription factor exhibits a developmentally regulated expression pattern . Dev. Biol. . 182 . 1 . 101–13 . 1997 . 9073453 . 10.1006/dbio.1996.8454 . To RQ . Swanson BJ . 3 . Lyons . GE . Konieczny . SF . free .
• Lemercier C, To RQ, Carrasco RA, Konieczny SF . The basic helix-loop-helix transcription factor Mist1 functions as a transcriptional repressor of myoD . EMBO J. . 17 . 5 . 1412–22 . 1998 . 9482738 . 10.1093/emboj/17.5.1412 . 1170489 .
• Pin CL, Lemercier C, Konieczny SF . Cloning of the murine Mist1 gene and assignment to mouse chromosome band 5G2-5G3 . Cytogenet. Cell Genet. . 86 . 3–4 . 219–22 . 2000 . 10575209 . 10.1159/000015342 . 42840963 .
• Pin CL, Rukstalis JM, Johnson C, Konieczny SF . The bHLH transcription factor Mist1 is required to maintain exocrine pancreas cell organization and acinar cell identity . J. Cell Biol. . 155 . 4 . 519–30 . 2001 . 11696558 . 10.1083/jcb.200105060 . 2198859 .
• Zhao Y . Identification of a basic helix-loop-helix transcription factor expressed in mammary gland alveolar cells and required for maintenance of the differentiated state . Mol. Endocrinol. . 20 . 9 . 2187–98 . 2006 . 16645041 . 10.1210/me.2005-0214 . Johansson C . Tran T . 3 . Bettencourt . R . Itahana . Y . Desprez . PY . Konieczny . SF . free .

Notes and References

1. McLellan AS, Langlands K, Kealey T . Exhaustive identification of human class II basic helix-loop-helix proteins by virtual library screening . Mech Dev . 119 . S285–91 . Sep 2003 . Suppl 1 . 14516699 . 10.1016/S0925-4773(03)00130-8. 5903576 .
2. Stevens JD, Roalson EH, Skinner MK . Phylogenetic and expression analysis of the basic helix-loop-helix transcription factor gene family: genomic approach to cellular differentiation . Differentiation . 76 . 9 . 1006–22 . Dec 2008 . 18557763 . 5728086 . 10.1111/j.1432-0436.2008.00285.x .
3. Web site: Entrez Gene: BHLHB8 basic helix-loop-helix domain containing, class B, 8.