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

Traffic ◽  
2020 ◽  
Vol 21 (11) ◽  
pp. 689-701
Author(s):  
Madeline Frank ◽  
Clara G. Citarella ◽  
Geraldine B. Quinones ◽  
Marvin Bentley
Keyword(s):  
Myosin Va ◽  
Myosin Vb

Roles for myosin Va in RNA transport and turnover

2012 ◽  
Vol 40 (6) ◽  
pp. 1416-1420 ◽  
Author(s):  
Mary W. McCaffrey ◽  
Andrew J. Lindsay
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Class V ◽  
Processing Bodies ◽  
Surface Receptors ◽  
P Bodies ◽  
Myosin Va ◽  
Myosin Vb ◽  
Actin Cables ◽  
The Brain

Mammals express three class V myosins. Myosin Va is widely expressed, but enriched in the brain, testes and melanocytes, myosin Vb is expressed ubiquitously, and myosin Vc is believed to be epithelium-specific. Myosin Va is the best characterized of the three and plays a key role in the transport of cargo to the plasma membrane. Its cargo includes cell-surface receptors, pigment and organelles such as the endoplasmic reticulum. It is also emerging that RNA and RNA-BPs (RNA-binding proteins) make up another class of myosin Va cargo. It has long been established that the yeast class V myosin, Myo4p, transports mRNAs along actin cables into the growing bud, and now several groups have reported a similar role for class V myosins in higher eukaryotes. Myosin Va has also been implicated in the assembly and maintenance of P-bodies (processing bodies), cytoplasmic foci that are involved in mRNA storage and degradation. The present review examines the evidence that myosin Va plays a role in the transport and turnover of mRNA.

Subcellular localization of GFP-myosin-V in live mouse melanocytes

1999 ◽  
Vol 112 (17) ◽  
pp. 2853-2865 ◽  
Author(s):  
V. Tsakraklides ◽  
K. Krogh ◽  
L. Wang ◽  
J.C. Bizario ◽  
R.E. Larson ◽  
...  
Keyword(s):  
Subcellular Localization ◽  
Actin Filaments ◽  
Expression Patterns ◽  
Intracellular Localization ◽  
Motor Domain ◽  
Chick Brain ◽  
Myosin V ◽  
Myosin Va ◽  
Myosin Vb ◽  
In Cells

Class-V myosins are two-headed actin-based mechanoenzymes that function in the transport and subcellular localization of organelles and possibly in the outgrowth of cellular processes. To determine which domains of myosin-V are involved in intracellular localization of this motor protein, we have expressed fusions of the green fluorescent protein with segments from two distinct myosin-V heavy chains. The expression patterns of constructs encoding four different domains of chick brain myosin-Va were compared to a single construct encoding the globular tail region of mouse myosin-Vb. In transfected mouse melanocytes, expression of the NH(2)-terminal head (catalytic domain) of chick brain myosin-Va codistributed with actin filaments throughout the cytoplasm. A similar construct encoding the myosin-Va head with the associated neck (light chain binding sites), also codistributed with actin filaments. The GFP-head-neck peptide was also highly concentrated in the tips of filopodia in B16 melanocytes wild type for myosin-Va (MYO5a gene), but was concentrated throughout the entire filopodia of S91-6 melanocytes derived from dilute mice with mutations in the MYO5a gene. Evidence is also presented that the globular tail of myosin-Va, but not myosin-Vb, targets this motor molecule to the centrosome as confirmed by colocalization in cells stained with antibodies to (gamma)-tubulin. Expression of the GFP-myosin-Va globular tail causes displacement of endogenous myosin-V from centrosomes as visualized by immunolabeling with antibodies to the head domain of myosin-V. Treatment with the microtubule-disrupting drug nocodazole markedly reduces myosin-V staining at the centrosome. In contrast, there was no detectable diminution of myosin-V staining at the centrosome in cells treated with the actin filament-disrupting drug cytochalasin D. Thus, while localization of the myosin-V motor domain to actin-rich regions is consistent with conventional models of actomyosin-based motility, localization to the centrosome occurs in the complete absence of the myosin-V motor domain and is dependent on intact microtubules.

scholarly journals Myosin Vb Is Associated with Plasma Membrane Recycling Systems

2001 ◽  
Vol 12 (6) ◽  
pp. 1843-1857 ◽  
Author(s):  
Lynne A. Lapierre ◽  
Ravindra Kumar ◽  
Chadwick M. Hales ◽  
Jennifer Navarre ◽  
Sheela G. Bhartur ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Fluorescent Protein ◽  
Mdck Cells ◽  
Cell Types ◽  
Dominant Negative ◽  
Membrane Recycling ◽  
Recycling System ◽  
Myosin Va ◽  
Myosin Vb ◽  
Recycling Systems

Myosin Va is associated with discrete vesicle populations in a number of cell types, but little is known of the function of myosin Vb. Yeast two-hybrid screening of a rabbit parietal cell cDNA library with dominant active Rab11a (Rab11aS20V) identified myosin Vb as an interacting protein for Rab11a, a marker for plasma membrane recycling systems. The isolated clone, corresponding to the carboxyl terminal 60 kDa of the myosin Vb tail, interacted with all members of the Rab11 family (Rab11a, Rab11b, and Rab25). GFP-myosin Vb and endogenous myosin Vb immunoreactivity codistributed with Rab11a in HeLa and Madin-Darby canine kidney (MDCK) cells. As with Rab11a in MDCK cells, the myosin Vb immunoreactivity was dispersed with nocodazole treatment and relocated to the apical corners of cells with taxol treatment. A green fluorescent protein (GFP)-myosin Vb tail chimera overexpressed in HeLa cells retarded transferrin recycling and caused accumulation of transferrin and the transferrin receptor in pericentrosomal vesicles. Expression of the myosin Vb tail chimera in polarized MDCK cells stably expressing the polymeric IgA receptor caused accumulation of basolaterally endocytosed polymeric IgA and the polymeric IgA receptor in the pericentrosomal region. The myosin Vb tail had no effects on transferrin trafficking in polarized MDCK cells. The GFP-myosin Va tail did not colocalize with Rab11a and had no effects on recycling system vesicle distribution in either HeLa or MDCK cells. The results indicate myosin Vb is associated with the plasma membrane recycling system in nonpolarized cells and the apical recycling system in polarized cells. The dominant negative effects of the myosin Vb tail chimera indicate that this unconventional myosin is required for transit out of plasma membrane recycling systems.

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