She4p/Dim1p interacts with the motor domain of unconventional myosins in the budding yeast, Saccharomyces cerevisiae.
She4p/Dim1p, a member of the UNC-45/CRO1/She4p (UCS) domain-containing protein family, is required for endocytosis, polarization of actin cytoskeleton, and polarization of ASH1 mRNA in Saccharomyces cerevisiae. We show herein that She4p/Dim1p is involved in endocytosis and actin polarization through interactions with the type I myosins Myo3p and Myo5p. Two-hybrid and biochemical experiments showed that She4p/Dim1p interacts with the motor domain of Myo3/5p through its UCS domain. She4p/Dim1p was required for Myo5p localization to cortical patch-like structures. 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. All of the amino acid substitutions caused by these mutations, V164I, N168I, N209S, and K377M, could suppress the defects of endocytosis and actin polarization of the she4/dim1 mutant as well. She4p/Dim1p also showed two-hybrid interactions with the motor domain of a type II myosin Myo1p and type V myosins Myo2p and Myo4p, and was required for proper localization of Myo4p, which regulates polarization of ASH1 mRNA. Our results suggest that She4p/Dim1p is required for structural integrity or regulation of the motor domain of unconventional myosins.
Toi
Hirofumi
H
Division of Molecular Interaction, Institute for Genetic Medicine, Hokkaido University Graduate School of Medicine, Japan.
Fujimura-Kamada
Konomi
K
Irie
Kenji
K
Takai
Yoshimi
Y
Todo
Satoru
S
Tanaka
Kazuma
K
D003598:Cytoskeletal Proteins; D024461:Myosin Type I / Q000378:metabolism*; D024462:Myosin Type II / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013696:Temperature
D003598:Cytoskeletal Proteins; C111369:SHE4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D024461:Myosin Type I; D024462:Myosin Type II; D024701:Myosin Type V