MAFA
Description
The MAFA (MAF bZIP transcription factor A) is a protein-coding gene located on chromosome 8.
MAFA (Mast cell function-associated antigen) is a type II membrane glycoprotein that was first identified on the surface of rat mucosal-type mast cells of the RBL-2H3 line. More recently, human and mouse homologues of MAFA have been discovered that are also (or only) expressed by NK and T-cells. MAFA is closely linked with the type 1 Fcɛ receptors in not only mucosal mast cells of humans and mice but also in the serosal mast cells of these same organisms. MAFA can function as both a channel for calcium ions and interact with other receptors to inhibit certain cell processes. Its function is based on its specialized structure, which contains many specialized motifs and sequences that allow its functions to take place. MAFA was initially discovered by Enrique Ortega and Israel Pecht in 1988 while studying the type 1 Fcɛ receptors (FcɛRI) and the unknown Ca2+ channels that allowed these receptors to work in the cellular membrane. Ortega and Pecht experimented through using a series of monoclonal antibodies on the RBL -2H3 line of rat mast cells. While experimenting and trying to find a specific antibody that would raise a response, the G63 monoclonal antibody was shown to raise a response by inhibiting the cellular secretions linked to the FcɛRI receptors in these rat mucosal mast cells. The G63 antibody attached to a specific membrane receptor protein that caused the inhibition process to occur. Specifically, the inhibition occurred by the G63 antibody and glycoprotein cross-linking so that the processes of inflammation mediator formation, Ca2+ intake into the cell, and the hydrolysis of phosphatidylinositides were all stopped.
MAFA is a transcription factor that activates insulin gene expression. It works synergistically with other transcription factors like NEUROD1/BETA2 and PDX1. MAFA binds to the insulin enhancer C1/RIPE3b element and a consensus TRE-type MARE 5‘-TGCTGACTCAGCA-3‘ DNA sequence.
MAFA is also known as INSDM, RIPE3b1, hMafA.
