oBelongs to the Id protein family (Id-1, 2, 3, 4)
oHLH protein
oInhibitor of differentiation
oPreferentially dimerizes with bHLH proteins
oActs in a dominant negative fashion
oPrevents bHLH proteins from forming dimers with other bHLH proteins
oPrevents bHLH proteins from binding DNA
oIs differentially regulated during differentiation of mesenchymal stem cells to different cell types