HSP90 is a molecular chaperone network which leads to homeostasis through modulating protein-DNA dynamics of components involved in RNA transcription, telomere maintenance, DNA repair, and DNA replication. It displays a protein binding capacity with an affinity for short hydrophobic amino acid motifs. These chaperones usually have short, low affinity interactions with their target protein to avoid interfering with the protein’s activity. Prokaryotes are known to typically contain one HSP90 gene which isn’t essential, while eukaryotes contain several HSP90 genes that are known to be essential.
HSP90 along with the p23 cochaperone are both proteins that interact with the protein subunit of a human telomerase (hTERT) and contribute to its enzymatic activity. HSP90 proteins have been known to promote DNA binding and nucleotide affinity for telomerase, and so HSP90 aids in maintaining telomere DNA length.
HSP90 isoforms Hsp82 and Hsc82 lead to telomeric DNA shortening.
DeZwann, Diane C., and Brian C. Freeman. "Trends Biochem Sci." Trends Biochem Sci. (2010): n. page.