RT Journal Article
SR Electronic
T1 Functional Characterization of Calmodulin-like Proteins, CML13 and CML14, as Novel Light Chains of Arabidopsis Class VIII Myosins
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2023.05.12.540561
DO 10.1101/2023.05.12.540561
A1 Kyle Symonds
A1 Howard J. Teresinski
A1 Bryan Hau
A1 Einat Sadot
A1 Vikas Dwivedi
A1 Eduard Belausov
A1 Sefi Bar-Sinai
A1 Motoki Tominaga
A1 Takeshi Haraguchi
A1 Kohji Ito
A1 Wayne A. Snedden
YR 2023
UL http://biorxiv.org/content/early/2023/05/13/2023.05.12.540561.abstract
AB Myosins are important motor proteins that associate with the actin cytoskeleton. Structurally, myosins function as heteromeric complexes where smaller light chains, such as calmodulin (CaM), bind to isoleucine-glutamine (IQ) domains in the neck regions to facilitate mechano-enzymatic activity. We recently identified Arabidopsis CaM-like (CML) proteins, CML13 and CML14 as interactors of proteins containing multiple IQ domains, including a member of the myosin VIII class. Here, using in vivo and in vitro assays we demonstrate that CaM, CML13, and CML14 bind the neck region of all four Arabidopsis myosin VIII isoforms. Among ten CML isoforms tested for in planta binding to myosins VIIIs, CaM, CML13, and CML14 gave the strongest signals using in planta split-luciferase protein-interaction assays. In vitro, recombinant CaM, CML13, and CML14 showed specific, high-affinity, calcium-independent binding to the IQ domains of myosin VIIIs. Subcellular localization analysis indicated that CaM, CML13, and CML14 co-localized to plasma membrane-bound puncta when co-expressed with RFP-myosin fusion proteins containing IQ- and tail-domains of myosin VIIIs. In addition, in vitro actin-motility assays using recombinant myosin holoenzymes demonstrated that CaM, CML13, and CML14 function as light chains for myosin VIIIs. Collectively, our data indicate that Arabidopsis CML13 and CML14 are novel myosin VIII light chains.Highlight Myosins are key proteins in the plant cytoskeleton, but the identity of their light chain components is unknown. Here, we show that calmodulin-like proteins function as novel myosin light chains.Competing Interest StatementThe authors have declared no competing interest.