Myo4p, one of two class V myosins in budding yeast, continuously transports messenger RNA (mRNA) cargo in the cell but is nonprocessive when characterized in vitro. The adapter protein She3p tightly binds to the Myo4p rod, forming a single-headed motor complex. In this paper, we show that two Myo4p-She3p motors are recruited by the tetrameric mRNA-binding protein She2p to form a processive double-headed complex. The binding site for She3p was mapped to a single alpha helix that protrudes at right angles from She2p. Processive runs of several micrometers on yeast actin-tropomyosin filaments were observed only in the presence of She2p, and, thus, motor activity is regulated by cargo binding. While moving processively, each head steps approximately 72 nm in a hand-over-hand motion. Coupling two high-duty cycle monomeric motors via a common cargo-binding adapter protein creates a complex with transport properties comparable with a single dimeric processive motor such as vertebrate myosin Va.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|