Alternatively Spliced Exon B of Myosin Va Is Essential for Binding the Tail-Associated Light Chain Shared by Dynein
详细信息 查看全文
- 作者：Zsuzsa Hó ; di ; Attila L. Né ; meth ; Lá ; szló ; Radnai ; Csaba Heté ; nyi ; Katalin Schlett ; Andrea Bodor ; Andrá ; s Perczel ; Lá ; szló ; Nyitray
- 刊名：Biochemistry
- 出版年：2006
- 出版时间：October 17, 2006
- 年：2006
- 卷：45
- 期：41
- 页码：12582 - 12595
- 全文大小：773K
- 年卷期：v.45,no.41(October 17, 2006)
- ISSN：1520-4995
文摘
A 10 kDa dynein light chain (DLC), previously identified as a tail light chain of myosin Va,may function as a cargo-binding and/or regulatory subunit of both myosin and dynein. Here, we identifyand characterize the binding site of DLC on myosin Va. Fragments of the human myosin Va tail and theDLC2 isoform were expressed, and their complex formation was analyzed by pull-down assays, gelfiltration, and spectroscopic methods. DLC2 was found to bind as a homodimer to a ~15 residue segment(Ile1280-Ile1294) localized between the medial and distal coiled-coil domains of the tail. The bindingregion contains the three residues coded by the alternatively spliced exon B (Asp1284-Lys1286). Removalof exon B eliminates DLC2 binding. Co-localization experiments in a transfected mammalian cell lineconfirm our finding that exon B is essential for DLC2 binding. Using circular dichroism, we demonstratethat binding of DLC2 to a ~85 residue disordered domain (Pro1235-Arg1320) induces some helicalstructure and stabilizes both flanking coiled-coil domains (melting temperature increases by ~7 
C). Thisresult shows that DLC2 promotes the assembly of the coiled-coil domains of myosin Va. Nuclear magneticresonance spectroscopy and docking simulations show that a 15 residue peptide (Ile1280-Ile1294) bindsto the surface grooves on DLC2 similarly to other known binding partners of DLCs. When our data aretaken together, they suggest that exon B and its associated DLC2 have a significant effect on the structureof parts of the coiled-coil tail domains and such a way could influence the regulation and cargo-bindingfunction of myosin Va.
C). Thisresult shows that DLC2 promotes the assembly of the coiled-coil domains of myosin Va. Nuclear magneticresonance spectroscopy and docking simulations show that a 15 residue peptide (Ile1280-Ile1294) bindsto the surface grooves on DLC2 similarly to other known binding partners of DLCs. When our data aretaken together, they suggest that exon B and its associated DLC2 have a significant effect on the structureof parts of the coiled-coil tail domains and such a way could influence the regulation and cargo-bindingfunction of myosin Va.