Functions of Class V Myosins in Neurons

Abstract

This minireview focuses on recent studies implicating class V myosins in organelle and macromolecule transport within neurons. These studies reveal that class V myosins play important roles in a wide range of fundamental processes occurring within neurons, including the transport into dendritic spines of organelles that support synaptic plasticity, the establishment of neuronal shape, the specification of polarized cargo transport, and the subcellular localization of mRNA. Class V Myosins Possess Features That Should Make Them Efficient Organelle MotorsEukaryotic cells, including neurons, use molecular motors to transport and properly distribute their organelles. Indeed, the demands placed on motor-dependent organelle transport are greatly amplified in neurons relative to other cell types because of the enormous lengths of their axon and dendrites (1). Neurons use microtubule-dependent motors (i.e. kinesins and dynein) to drive long-range bidirectional transport of organelles within these processes. In contrast, short-range organelle movements in the periphery, such as within dendritic spines, appear to be driven by actin-based motors, i.e. myosins.Among the ϳ14 myosin classes in vertebrates, the class V myosins have so far received the most attention with regard to short-range organelle and macromolecule transport within neurons, as well as within other cell types (reviewed in Ref. 2). Mice and humans possess three class V myosin genes (MYO5A,

A novel role for Myosin-Va in mitochondrial fission

“…The mitochondrial elongation triggered by myosin-Va knockdown in A375 melanoma cells is consistent with previously reported increase in mitochondrial size following knockdown of myosin-Va in neurons 18 . The diminished number of fission events observed in A375 melanoma cells is consistent to a role of myosin-Va in mitochondrial fission, as it has been widely shown that a deficiency in the fission process results in mitochondrial elongation upon inactivation of key proteins of the fission machinery, such as myosin II 26 Given the results in our ionomycin experiments, it is interesting to consider that myosin-Va activity is calciumdependent 38,48,49 . Among other mechanisms, it has been shown that myosin-Va associates to the ER and binds to the ryanodine calcium receptor channels on the ER membrane, and also responds to ER-derived calcium by associating with vesicles and directing them to specific sites 50 .…”

Colonic neuronal loss and delayed motility induced by high‐fat diet occur independently of changes in the major groups of microbiota in Swiss mice

“…The primary and secondary antibodies that were used for immunofluorescence are summarized in Table 1. The wholemount preparations were incubated with immunoreactive (IR) antibodies for the following proteins: myosin-V (myosin-V-IR general neuronal population 25 ), neuronal nitric oxide synthase (nNOS-IR subpopulation), vasoactive intestinal peptide (VIP-IR subpopulation), calretinin (CALR-IR subpopulation), and S100 (S100-IR glial cells). Immunofluorescent labeling was performed with different wholemount preparations for each primary antibody, with the exception of double-labeling nNOS/VIP.…”

A Subset of Autism-Associated Genes Regulate the Structural Stability of Neurons

“…Several myosin isoforms play central roles in regulating neurite outgrowth, as well as dendritic spine structural plasticity (Wylie et al, 1998; Wylie and Chantler, 2003; Ryu et al, 2006; Hammer and Wagner, 2013; Kneussel and Wagner, 2013; Yoshii et al, 2013; Koskinen et al, 2014; Ultanir et al, 2014). Among all isoforms, MYO16 (Myr8 or NYAP3) was recently implicated in ASD (Wang et al, 2009; Connolly et al, 2013; Kenny et al, 2014; Roberts et al, 2014; Liu et al, 2015b).…”