HSF4 Human Recombinant Protein

Heat-shock transcription factors (HSFs) activate heat-shock response genes under conditions of heat or other stresses. HSF4 lacks the carboxyl-terminal hydrophobic repeat which is shared among all vertebrate HSFs and has been suggested to be involved in the negative regulation of DNA binding activity. Two alternatively spliced transcripts encoding distinct isoforms and possessing different transcriptional activity have been described. [provided by RefSeq, Jul 2008]

HSF4: DNA-binding protein that specifically binds heat shock promoter elements (HSE). Isoform HSF4A represses transcription while the isoform HSF4B activates transcription. Defects in HSF4 are the cause of cataract, zonular (CZ). A form of zonular cataract. Zonular or lamellar cataracts are opacities, broad or narrow, usually consisting of powdery white dots affecting only certain layers or zones between the cortex and nucleus of an otherwise clear lens. The opacity may be so dense as to render the entire central region of the lens completely opaque, or so translucent that vision is hardly if at all impeded. Zonular cataracts generally do not involve the embryonic nucleus, though sometimes they involve the fetal nucleus. Usually sharply separated from a clear cortex outside them, they may have projections from their outer edges known as riders or spokes. Defects in HSF4 are the cause of cataract Marner type (CAM). A form of cataract with variable and progressive opacities. Affected individuals present with zonular cataract, although some have nuclear, anterior polar, or stellate cataract. Finger malformation is observed in some kindreds. Belongs to the HSF family. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Transcription, coactivator/corepressor; DNA-binding; Cell development/differentiation

Chromosomal Location of Human Ortholog: 16q21

Cellular Component: nucleoplasm

Molecular Function: sequence-specific DNA binding; transcription factor activity; transcription corepressor activity; protein phosphatase binding

Biological Process: histone H3-K9 demethylation; camera-type eye development; transcription, DNA-dependent; regulation of transcription, DNA-dependent; positive regulation of cell proliferation; positive regulation of transcription from RNA polymerase II promoter; negative regulation of transcription from RNA polymerase II promoter; positive regulation of cell differentiation; cell development

Disease: Cataract 5, Multiple Types