Tracking UNC-45 chaperone-myosin interaction with a titin mechanical reporter

Christian M. Kaiser, Pawel Bujalowski, Liang Ma, John Anderson, Henry F. Epstein, Andres Oberhauser

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Myosins are molecular motors that convert chemical energy into mechanical work. Allosterically coupling ATP-binding, hydrolysis, and binding/dissociation to actin filaments requires precise and coordinated structural changes that are achieved by the structurally complex myosin motor domain. UNC-45, a member of the UNC-45/Cro1/She4p family of proteins, acts as a chaperone for myosin and is essential for proper folding and assembly of myosin into muscle thick filaments in vivo. The molecular mechanisms by which UNC-45 interacts with myosin to promote proper folding of the myosin head domain are not known. We have devised a novel approach, to our knowledge, to analyze the interaction of UNC-45 with the myosin motor domain at the single molecule level using atomic force microscopy. By chemically coupling a titin I27 polyprotein to the motor domain of myosin, we introduced a mechanical reporter. In addition, the polyprotein provided a specific attachment point and an unambiguous mechanical fingerprint, facilitating our atomic force microscopy measurements. This approach enabled us to study UNC-45-motor domain interactions. After mechanical unfolding, the motor domain interfered with refolding of the otherwise robust I27 modules, presumably by recruiting them into a misfolded state. In the presence of UNC-45, I27 folding was restored. Our single molecule approach enables the study of UNC-45 chaperone interactions with myosin and their consequences for motor domain folding and misfolding in mechanistic detail.

Original languageEnglish (US)
Pages (from-to)2212-2219
Number of pages8
JournalBiophysical Journal
Volume102
Issue number9
DOIs
StatePublished - May 2 2012

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Connectin
Myosins
Polyproteins
Atomic Force Microscopy
Dermatoglyphics
Actin Cytoskeleton
Hydrolysis
Adenosine Triphosphate
Muscles

ASJC Scopus subject areas

  • Biophysics

Cite this

Tracking UNC-45 chaperone-myosin interaction with a titin mechanical reporter. / Kaiser, Christian M.; Bujalowski, Pawel; Ma, Liang; Anderson, John; Epstein, Henry F.; Oberhauser, Andres.

In: Biophysical Journal, Vol. 102, No. 9, 02.05.2012, p. 2212-2219.

Research output: Contribution to journalArticle

Kaiser, Christian M. ; Bujalowski, Pawel ; Ma, Liang ; Anderson, John ; Epstein, Henry F. ; Oberhauser, Andres. / Tracking UNC-45 chaperone-myosin interaction with a titin mechanical reporter. In: Biophysical Journal. 2012 ; Vol. 102, No. 9. pp. 2212-2219.
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