A novel labeling strategy reveals that myosin Va and myosin Vb bind the same dendritically polarized vesicle population

Abstract

Neurons are specialized cells with a polarized geometry and several distinct subdomains that require specific complements of proteins. Delivery of transmembrane proteins requires vesicle transport, which is mediated by molecular motor proteins. The myosin V family of motor proteins mediates transport to the barbed end of actin filaments, and little is known about the vesicles bound by myosin V in neurons. We developed a novel strategy to visualize myosin V‐labeled vesicles in cultured hippocampal neurons and systematically characterized the vesicle populations labeled by myosin Va and Vb. We find that both myosins bind vesicles that are polarized to the somatodendritic domain where they undergo bidirectional long‐range transport. A series of two‐color imaging experiments showed that myosin V specifically colocalized with two different vesicle populations: vesicles labeled with the transferrin receptor and vesicles labeled by low‐density lipoprotein receptor. Finally, coexpression with Kinesin‐3 family members found that myosin V binds vesicles concurrently with KIF13A or KIF13B, supporting the hypothesis that coregulation of kinesins and myosin V on vesicles is likely to play an important role in neuronal vesicle transport. We anticipate that this new assay will be applicable in a broad range of cell types to determine the function of myosin V motor proteins.

KAP is the neuronal organelle adaptor for Kinesin-2 KIF3AB and KIF3AC

“…1E). Without linker, correlation coefficients were consistently between 0.3 and 0.4, typical values for cellular structures and a largely soluble protein that does not specifically colocalize (Frank et al, 2020). Linker addition and the resulting colocalization caused high coefficients for KIF3B (0.75) and KIF3C (0.88).…”

“…Transport parameters differ between populations and act as a quantitative “signature” for specific organelles (Frank et al, 2020; Yang et al, 2019; Burack et al, 2000; Niwa et al, 2008; Koppers and Farías, 2021; Bodakuntla et al, 2020; De Pace et al, 2020; Lo et al, 2011; Farfel-Becker et al, 2019; Bommel et al, 2019). We systematically quantified the transport parameters (i.e., velocity and run length) of the three organelle populations (Fig.…”

Arabidopsis thaliana myosin XIK is recruited to the Golgi through interaction with a MyoB receptor

“…8c) which could possibly be modulated through environmental/local signals. Note, MyoVa and MyoVb were recently shown to collocate to the same population of neuronal vesicles with the authors proposing recruitment of inactive myosins to the cargo with subsequent activation on the vesicle surface controlled through a local signal 54 . Future studies are required to understand how MRF7, and other potential receptors regulate myosin recruitment to the Golgi surface which ultimately controls Golgi dynamics.…”

KIF13A—A Key Regulator of Recycling Endosome Dynamics

“…KIF13A facilitates the trafficking of a subset of glutamate receptors to the synapse through Rab11-FIP2 endosomes during LTP induction ( Gutierrez et al, 2021 ). Additionally, KIF13A or KIF13B have been observed on myosin-V labelled vesicles during the neuronal vesicle transport process ( Frank et al, 2020 ). Similarly, KIF13A and KIF13B are shown to associate with a subset of dendritic vesicles and TfR-positive vesicles in dendritic cells ( Jenkins et al, 2012 ).…”