Classification and Function of the Basic Helix-loop-helix Protein Class

Abstract: The basic helix-loop-helix-like protein belongs to a protein superfamily， and the most obvious character of this superfamily is the highly conserved helix-loop-helix domain， which exists in organisms from bacteria to mammals. Based on the DNA-binding activity， existence of conserved motifs outside the helix-loop-helix domain and binding speciality of the E-box， helix-loop-helix superfamily was classified into six subfamilies. Proteins in this superfamily function through formation of homodimer or heterodimer between different family members. Most of the proteins in this superfamily are transcription factors， and usually function to change cellular course by depressing or activation genes that is related to growth or differentiation. It has been demonstrated that this kind of proteins is involved in cell growth， cell senescence， cancer develop， nerves development and drosophila sex decision. Recent studies indicated that helix-loop-helix proteins also play important roles in plant， mediating signal transduction in processes such as freezing tolerance， drought tolerance and root development， anther development， etc.. In this paper， we give a brief review of the classification and functions of this protein superfamily.

CSTR: 32200.14.cjcb.2009.02.0011