Functional characterization of calmodulin-like proteins, CML13 and CML14, as novel light chains of Arabidopsis class VIII myosins.

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 region 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 myosin VIII.

Documentation of Microtubule Collisions with Myosin VIII ATM1 Containing Membrane-Associated Structures.

Collisions of microtubules with membrane-associated structures containing myosin VIII were recently described, and these data suggested that such collisions can happen between microtubules and other membrane-associated proteins. Such collisions may contribute to a coordinated organization between microtubules and membrane-associated proteins especially in cases of low lateral diffusion rates of the protein. Coordinated organization of cortical cytoskeleton and membrane structures can have consequences on membrane compartmentalization and downstream signaling.

Collisions of Cortical Microtubules with Membrane Associated Myosin VIII Tail.

The distribution of myosin VIII ATM1 tail in association with the plasma membrane is often observed in coordination with that of cortical microtubules (MTs). The prevailing hypothesis is that coordination between the organization of cortical MTs and proteins in the membrane results from the inhibition of free lateral diffusion of the proteins by barriers formed by MTs. Since the positioning of myosin VIII tail in the membrane is relatively stable, we ask: can it affect the organization of MTs? Myosin VIII ATM1 tail co-localized with remorin 6.