Role of the Myosin Assembly Protein UNC-45 as a Molecular Chaperone for Myosin

• Published in: Science (American Association for the Advancement of Science) Vol. 295; no. 5555; pp. 669 - 671
• Main Authors: Barral, José M., Hutagalung, Alex H., Brinker, Achim, Hartl, F. Ulrich, Epstein, Henry F.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 25.01.2002; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Aggregation; Amino Acid Motifs; Amino Acid Sequence; Amino acids; Animals; Antibodies; Binary mixtures; Binding Sites; Biochemistry; Biological and medical sciences; Caenorhabditis elegans - genetics; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - chemistry; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; Cell Line; Cell motility; Cloning, Molecular; Fundamental and applied biological sciences. Psychology; HSP70 Heat-Shock Proteins - genetics; HSP70 Heat-Shock Proteins - metabolism; HSP90 Heat-Shock Proteins - genetics; HSP90 Heat-Shock Proteins - metabolism; Molecular and cellular biology; Molecular chaperones; Molecular Chaperones - chemistry; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Molecular genetics; Molecular Sequence Data; Molecules; Muscle proteins; Myosin; Myosins - metabolism; Peptide Fragments - metabolism; Physiological aspects; Protein Binding; Protein Structure, Tertiary; Proteins; Recombinant Proteins - chemistry; Recombinant Proteins - metabolism; Roles; Space life sciences; Non-programmatic
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1066648

The organization of myosin into motile cellular structures requires precise temporal and spatial regulation. Proteins containing a UCS (UNC-45/CRO1/She4p) domain are necessary for the incorporation of myosin into the contractile ring during cytokinesis and into thick filaments during muscle development. We report that the carboxyl-terminal regions of UNC-45 bound and exerted chaperone activity on the myosin head. The amino-terminal tetratricopeptide repeat domain of UNC-45 bound the molecular chaperone Hsp90. Thus, UNC-45 functions both as a molecular chaperone and as an Hsp90 co-chaperone for myosin, which can explain previous findings of altered assembly and decreased accumulation of myosin in UNC-45 mutants of Caenorhabditis elegans.