High impact information on MYO5

• Deletion of the genes MYO3 and MYO5, which encode the yeast type I myosins, almost abolished growth [1].
• A double-deleted mutant complemented with a MYO5 temperature-sensitive allele (myo5-1) showed a strong defect in the internalization step of receptor-mediated endocytosis, whereas the secretory pathway remained apparently unaffected [1].
• Consistent with this, Myo5p patches assemble but do not localize to sites of polarized cell surface growth in a VRP1 deletion mutant [2].
• Moreover, incubation of yeast cells at 37 degrees C results in transient depolarization of both Myo5p patches and the actin cytoskeleton [2].
• Immunolocalization of the myc-tagged SH3 domain of Myo5p reveals diffuse cytoplasmic staining [2].

Biological context of MYO5

• Using random mutagenesis of the motor region of MYO5, we identified four independent dominant point mutations that suppress the temperature-sensitive growth phenotype of the she4/dim1 null mutant [3].
• Myo5p is localized as punctate, cortical structures enriched at sites of polarized cell growth [2].

Anatomical context of MYO5

• Mutations in the budding yeast myosins-I (MYO3 and MYO5) cause defects in the actin cytoskeleton and in the endocytic uptake [4].
• The peak of Myo5 association with cortical patches immediately precedes the fast movement of Arp2/3 complex-associated structures away from the plasma membrane, thus correlating precisely with the proposed vesicle scission event [5].

Associations of MYO5 with chemical compounds

• We find that latrunculin-A-induced depolymerization of F-actin results in loss of Myo5p patches [2].

Regulatory relationships of MYO5

• Consistently, we have recently demonstrated, using fluorescence microscopy, that Myo5p is able to induce cytosol-dependent actin polymerization on the surface of Sepharose beads [4].
• In vitro, She4p stimulates binding of Myo5p to filamentous actin [6].

Other interactions of MYO5

• The budding yeast Saccharomyces cerevisiae has two functionally redundant myosin-I isoforms encoded by the MYO3 and MYO5 genes [7].
• She4p/Dim1p was required for Myo5p localization to cortical patch-like structures [3].

References