HLH Motif

Cancer Terms -> Retired Concepts -> Retired Concept 2003 -> HLH Motif

HLH Motif Definition

In transcription regulators of cell cycle control, cell determination, and cell differentiation, the conserved HLH (Helix-Loop-Helix) Domain of 40-50 amino acids forms amphipathic helixes between a variable loop. HLHs typically mediate homo- or heterodimerization through interactions with self or other motifs to activate or inactivate trans-activating function. The N-helix often contains DNA-interacting basic residues; the C-helix typically contains characteristically spaced hydrophobic residues. An adjacent basic region of 15 amino acids in most HLH proteins binds to DNA. Basic (b)HLH proteins bind variants of the 'CANNTG' E-box. Proteins lacking the basic domain act as inhibitors, failing to bind DNA. bHLH proteins exhibit specific dimerization partner combinations. In calcium-binding proteins, certain invariant hydrophilic loop residues in the HLH motif bind calcium. (NCI)

HLH Motif Synonyms

HLH Motif

HLH Motif

HLH Motif Definition

HLH Motif Synonyms

Terms in HLH Motif category