Recombinant Danio rerio Heat shock protein HSP 90-alpha 1 (hsp90a.1), partial

Function

Molecular chaperone that promotes the maturation, structural maintenance and proper regulation of specific target proteins involved for instance in cell cycle control and signal transduction. Undergoes a functional cycle that is linked to its ATPase activity which is essential for its chaperone activity. This cycle probably induces conformational changes in the client proteins, thereby causing their activation. Interacts dynamically with various co-chaperones that modulate its substrate recognition, ATPase cycle and chaperone function. Engages with a range of client protein classes via its interaction with various co-chaperone proteins or complexes, that act as adapters, simultaneously able to interact with the specific client and the central chaperone itself. Recruitment of ATP and co-chaperone followed by client protein forms a functional chaperone. After the completion of the chaperoning process, properly folded client protein and co-chaperone leave HSP90 in an ADP-bound partially open conformation and finally, ADP is released from HSP90 which acquires an open conformation for the next cycle (By similarity). Plays a key role in slow and fast muscle development in the embryo. Plays a role in myosin expression and assembly (PubMed:10364427, PubMed:17586488, PubMed:18182494, PubMed:18256191)

Subcellular Location

Melanosome; Cytoplasm, myofibril, sarcomere, Z line; Cytoplasm, myofibril, sarcomere, A band; Cytoplasm, perinuclear region

Tissue Specificity

Strongly expressed in the early embryos within the somitic slow muscle progenitors, the adaxial cells that lie on either side of the notochord but not the notochord. Also expressed during the early differentiation of fast fibers. Detected in developing cardiac muscles and pectoral fin primordia. Not detected in mature muscle fibers

Subunit

Homodimer (By similarity). Interacts with unc45b and myosin

• Lele Z. et al. Disruption of zebrafish somite development by pharmacologic inhibition of Hsp90. — Dev. Biol. (1999)
• Etard C. et al. The UCS factor Steif/Unc-45b interacts with the heat shock protein Hsp90a during myofibrillogenesis. — Dev. Biol. (2007)
• Etard C. et al. Shuttling of the chaperones Unc45b and Hsp90a between the A band and the Z line of the myofibril. — J. Cell Biol. (2008)
• Howe K. et al. The zebrafish reference genome sequence and its relationship to the human genome. — Nature (2013)
• PubMed: CI-31S8NPLB6QD1F (JUL-)
• Krone P.H. et al. HSP 90 alpha and HSP 90 beta genes are present in the zebrafish and are differentially regulated in developing embryos. — Biochem. Biophys. Res. Commun. (1994)
• Sass J.B. et al. Specific localization of zebrafish hsp90 alpha mRNA to myoD-expressing cells suggests a role for hsp90 alpha during normal muscle development. — Mech. Dev. (1996)
• Sass J.B. et al. Restricted expression of the zebrafish hsp90alpha gene in slow and fast muscle fiber lineages. — Int. J. Dev. Biol. (1999)