3.9 kb

295 amino acids, MW 43 kDa

HLF is normally expressed in hepatocytes and liver-derived cell lines, and, to a lesser extent, in lung, kidney and neurons of the central nervous system; it is not expressed in hematopoietic tissues or cell lines

nuclear

the normal function of HLF is largely unknown; HLF is a member of the PAR (proline and acidic amino acid-rich region) subfamily of b/ZIP (basic region leucine zipper) transcription factors; PAR and b/ZIP proteins bind to the DNA as dimers; HLF acts as a transcriptionnal transactivator; there are evidences that HLF protein transactivates factor VIII and factor IX genes, by binding as a homodimer (HLF/HLF) or a heterodimer with one albumin D-element binding protein sub unit (HLF/DBP), to multiple sites in the promoter of these genes; in the mouse central nervous system ontogeny, HLF expression increases markedly with synaptogenesis, suggesting that HLF plays a role in the function of adult differentiated neurons

other members of the b/ZIP PAR subfamily; in mammals: albumin D-element binding protein (DBP) and thyrotroph embryonic factor / vitellogenin gene binding protein (TEF/VBP); like HLF, they are transcription activators; the three proteins have an ability to form heterodimers with one another through the leucine-zipper domain; in other species : vitellogenin binding protein (VBP) in the chicken and Ces-2 gene in the nematode Caenorhabditis elegans