title: Drosophila myosin-XX functions as an actin-binding protein to facilitate the interaction between Zyx102 and actin.
abstract: The class XX myosin is a member of the diverse myosin superfamily and exists in insects and several lower invertebrates. DmMyo20, the class XX myosin in Drosophila, is encoded by dachs, which functions as a crucial downstream component of the Fat signaling pathway, influencing growth, affinity, and gene expression during development. Sequence analysis shows that DmMyo20 contains a unique N-terminal extension, the motor domain, followed by one IQ motif, and a C-terminal tail. To investigate the biochemical properties of DmMyo20, we expressed several DmMyo20 truncated constructs containing the motor domain in the baculovirus/Sf9 system. We found that the motor domain of DmMyo20 had neither ATPase activity nor the ability to bind to ATP, suggesting that DmMyo20 does not function as a molecular motor. We found that the motor domain of DmMyo20 could specifically bind to actin filaments in an ATP-independent manner and enhance the interaction between actin filaments and Zyx102, a downstream component of DmMyo20 in the Fat signaling pathway. These results suggest that DmMyo20 functions as a scaffold protein, but not as a molecular motor, in a signaling pathway controlling cell differentiation.
authors.affiliation: Group of Cell Motility and Muscle Contraction, National Laboratory of Integrated Management of Insect Pests and Rodents, Institute of Zoology, Chinese Academy of Sciences , Beijing 100101, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
authors.forename: Howard D
authors.initials: HD
authors.lastname: White
authors.forename: Xiang-Dong
authors.initials: XD
authors.lastname: Li
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D003001:Cloning, Molecular; D029721:Drosophila Proteins / Q000737:chemistry / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009218:Myosins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D060589:Zyxin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000199:Actins; D029721:Drosophila Proteins; D008840:Microfilament Proteins; C499520:Zyx protein, Drosophila; D060589:Zyxin; D009218:Myosins