Two Distinct Regions in a Yeast Myosin-V Tail Domain Are Required for the Movement of Different Cargoes

Catlett, Natalie L.; Duex, Jason E.; Tang, Fusheng; Weisman, Lois S.

doi:10.1083/jcb.150.3.513

Cited by 91 publications

(120 citation statements)

References 48 publications

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“…Our observation that the GTD is required for melanosome targeting agrees with a number of recent studies implicating this domain in cargo binding, most strikingly those involving the yeast type V myosin Myo2p and its interactions with secretory vesicles (Schott et al, 1999) and the vacuole membrane (Catlett et al, 2000). Our demonstration that the GTD is not sufficient for melanosome targeting contrasts, however, with the work on Myo2p, where the ability of its GTD to associate with cargo and to generate a dominant negative phenotype indicates that its GTD is sufficient for targeting (Schott et al, 1999;Catlett et al, 2000).…”

Section: Identification Of Myosin Va Heavy Chain Sequences Required Fsupporting

confidence: 79%

Rab27a Is an Essential Component of Melanosome Receptor for Myosin Va

Wang

Rao

et al. 2002

MBoC

160

182

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Melanocytes that lack the GTPase Rab27a (ashen) are disabled in myosin Va-dependent melanosome capture because the association of the myosin with the melanosome surface depends on the presence of this resident melanosomal membrane protein. One interpretation of these observations is that Rab27a functions wholly or in part as the melanosome receptor for myosin Va (Myo5a). Herein, we show that the ability of the myosin Va tail domain to localize to the melanosome and generate a myosin Va null (dilute) phenotype in wild-type melanocytes is absolutely dependent on the presence of exon F, one of two alternatively spliced exons present in the tail of the melanocyte-spliced isoform of myosin Va but not the brain-spliced isoform. Exon D, the other melanocyte-specific tail exon, is not required. Similarly, the ability of full-length myosin Va to colocalize with melanosomes and to rescue their distribution in dilute melanocytes requires exon F but not exon D. These results predict that an interaction between myosin Va and Rab27a should be exon F dependent. Consistent with this, Rab27a present in detergent lysates of melanocytes binds to beads coated with purified, full-length melanocyte myosin Va and melanocyte myosin Va lacking exon D, but not to beads coated with melanocyte myosin Va lacking exon F or brain myosin Va. Moreover, the preparation of melanocyte lysates in the presence of GDP rather than guanosine-5Ј-O-(3-thio)triphosphate reduces the amount of Rab27a bound to melanocyte myosin Va-coated beads by approximately fourfold. Finally, pure Rab27a does not bind to myosin Va-coated beads, suggesting that these two proteins interact indirectly. Together, these results argue that Rab27a is an essential component of a protein complex that serves as the melanosome receptor for myosin Va, suggest that this complex contains at least one additional protein capable of bridging the indirect interaction between Rab27a and myosin Va, and imply that the recruitment of myosin Va to the melanosome surface in vivo should be regulated by factors controlling the nucleotide state of Rab27a.

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Section: Identification Of Myosin Va Heavy Chain Sequences Required Fsupporting

confidence: 79%

Rab27a Is an Essential Component of Melanosome Receptor for Myosin Va

Wang

Rao

et al. 2002

MBoC

160

182

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“…The observation that both Myo2p and Vac17p are mislocalized is consistent with a defect in the association of the Myo2p-Vac17p complex. When myosin motors are defective in forming organelle-specific complexes, the motor and organelle specific receptor are mis-localized (Catlett et al, 2000;Lipatova et al, 2008;Peng and Weisman, 2008). Surprisingly, the levels of Vac17p in the ptc1⌬ mutant are significantly lower than that in a wild-type strain ( Figure 7B).…”

Section: Discussionmentioning

confidence: 87%

“…Both myo2-2p, which is defective in binding Vac17p and myo2p-Y1415E, which is defective in binding Ypt31/32p, are mis-localized (Catlett et al, 2000;Lipatova et al, 2008; data not shown). These observations suggest the possibility that PTC1 regulates organelle inheritance by controlling the association of the Myo2p with organellespecific receptors.…”

Section: Ptc1 Is Required For the Proper Association Of The Vacuole Tmentioning

confidence: 99%

PTC1Is Required for Vacuole Inheritance and Promotes the Association of the Myosin-V Vacuole-specific Receptor Complex

Jin

Eves

Tang

et al. 2009

MBoC

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Organelle inheritance occurs during cell division. In Saccharomyces cerevisiae, inheritance of the vacuole, and the distribution of mitochondria and cortical endoplasmic reticulum are regulated by Ptc1p, a type 2C protein phosphatase. Here we show that PTC1/VAC10 controls the distribution of additional cargoes moved by a myosin-V motor. These include peroxisomes, secretory vesicles, cargoes of Myo2p, and ASH1 mRNA, a cargo of Myo4p. We find that Ptc1p is required for the proper distribution of both Myo2p and Myo4p. Surprisingly, PTC1 is also required to maintain the steady-state levels of organelle-specific receptors, including Vac17p, Inp2p, and Mmr1p, which attach Myo2p to the vacuole, peroxisomes, and mitochondria, respectively. Furthermore, Vac17p fused to the cargo-binding domain of Myo2p suppressed the vacuole inheritance defect in ptc1⌬ cells. These findings suggest that PTC1 promotes the association of myosin-V with its organelle-specific adaptor proteins. Moreover, these observations suggest that despite the existence of organelle-specific receptors, there is a higher order regulation that coordinates the movement of diverse cellular components. INTRODUCTIONDuring each cell cycle, cytoplasmic organelles are actively distributed between dividing cells to maintain organelle copy number and volume. The yeast Saccharomyces cerevisiae is an excellent model system for studying the spatial and temporal control of organelle inheritance. In yeast, several organelles are transmitted from mother to daughter cells. These include the vacuole, mitochondria, the endoplasmic reticulum (ER), late-Golgi elements and peroxisomes (reviewed in Weisman, 2006).Early in the cell cycle, a portion of each organelle is transported into the emerging bud. The polarized transport of most organelles from the mother to the bud is an active process that requires the actin cytoskeleton, myosin-V motors, and receptor proteins, which physically connect the motor to organelle cargoes (Beach et al., 2000;Yin et al., 2000;Boldogh et al., 2001;Barr, 2002;Bretscher, 2003;Du et al., 2004;Fagarasanu et al., 2006bFagarasanu et al., , 2007Weisman, 2006). Thus, formation of a complex between the motor and receptor protein is important for polarized organelle transport.Similar to yeast, in vertebrates, myosin-V motors move cargoes along the actin cytoskeleton. The best studied cargo of vertebrate myosin-V are melanosomes, which are moved in melanocytes by myosin-Va. Melanosomes attach to myosin-Va through Rab27a and melanophilin (Fukuda and Kuroda, 2002;Wu et al., 2002). Rab27a, through geranylgeranylation, attaches to the melanosome membrane, and melanophilin connects myosin-Va and Rab27a. Myosin-V-based intracellular movement has been analyzed in many other eukaryotes, including frogs, fish, mammals, and plants; plant myosin-XI is the functional homologue of yeast and vertebrate myosin-V ( Kinkema and Schiefelbein, 1994;Provance and Mercer, 1999;Tuma and Gelfand, 1999;Desnos et al., 2007;Li and Nebenfuhr, 2007;Sheets et al., 2007;Shimmen, 2007).Ge...

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“…8E), suggesting strongly that Myo2-573p retains affinity for Ypt11p. The myo2-573 mutation induces six substitutions (Val 1189 to Ala, Val 1288 to Gly, Lys 1500 to Met, Pro 1529 to Ser, Glu 1546 to Gly, and Lys 1559 to Arg), and none of these overlap with any critical residues, whose substitution is reported to induce defects in the transport of secretory vesicles or vacuoles (8,32). It is conceivable that the myo2-573 mutation reduces the affinity of Myo2p for a factor for mitochondrial distribution.…”

Section: Discussionmentioning

confidence: 99%

Complex Formation with Ypt11p, a rab-Type Small GTPase, Is Essential To Facilitate the Function of Myo2p, a Class V Myosin, in Mitochondrial Distribution in Saccharomyces cerevisiae

Itoh

Watabe

Toh‐e

et al. 2002

Molecular and Cellular Biology

127

138

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We identified Ypt11p, a rab-type small GTPase, by its functional and two-hybrid interaction with Myo2p, a class V myosin of the budding yeast Saccharomyces cerevisiae. The tail domain of Myo2p was coimmunoprecipitated with Ypt11p, suggesting that Ypt11p forms a complex with Myo2p at its tail domain in vivo. Mutational analysis of YPT11 suggests that Myo2p is a putative effector of Ypt11p. Deletion of YPT11 induced partial delay of mitochondrial transmission to the bud, and overexpression of YPT11 resulted in mitochondrial accumulation in the bud, indicating that Ypt11p acts positively on mitochondrial distribution toward the bud. We isolated two myo2 mutants, myo2-338 and myo2-573, which showed genetic interactions with YPT11. The myo2-573 mutation, identified by a synthetic lethal interaction with ypt11-null, induced a defect in mitochondrial distribution toward the bud, indicating that Myo2p plays a crucial role in polarized distribution of mitochondria. The myo2-338 mutation was identified as the mutation that abolished the effect of overexpressed YPT11, such as the Ypt11p-dependent accumulation of mitochondria in the bud, and the affinity of Myo2p for Ypt11p was reduced. These results indicate that complex formation of Ypt11p with Myo2p accelerates the function of Myo2p for mitochondrial distribution toward the bud.Class V myosins, a crucial actin-based motor for organelle transport, are conserved from yeast to mammals and contain an N-terminal motor domain for interacting with actin structures and a C-terminal tail domain for the binding of cargo (5, 40). In the dilute mouse, which carries a defective class V myosin (myosin-Va), melanosomes localize in the central cell body of melanocytes instead of at the dendritic tip, indicating a failure of pigment transport (30). In the budding yeast, Myo2p is an essential class V myosin (1,574 amino acids) and localizes at the tip of growing buds (17, 23). Defects in Myo2p abolish polarized growth by disrupting the polarized delivery of secretory vesicles and lead to defects in vacuole inheritance, delivery of the late Golgi element, and transport of Kar9p for the orientation of mitotic spindles (13,17,31,44). Therefore, Myo2p is essential for the polarized transport of organelles, such as secretory vesicles, vacuoles, late Golgi element, and Kar9p, along actin cables.rab-type small GTPases participate in processes that underlie the targeting and fusion of membrane vesicles to their acceptor membrane. Small GTPases have three motifs for GTP binding and hydrolysis and have an effector domain between the first and second motifs for interaction with their effectors (2). Several putative effectors of rab-type small GTPases have been identified, and the diversity of their functions suggests that rab-type small GTPases play a more complex role than controlling the recognition of vesicles with membranes. It is reported that rab-type small GTPases interact with class V myosins. myosin-Vb colocalizes with and shows two-hybrid interaction with Rab11a, a rab-type small GTPase f...

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Two Distinct Regions in a Yeast Myosin-V Tail Domain Are Required for the Movement of Different Cargoes

Cited by 91 publications

References 48 publications

Rab27a Is an Essential Component of Melanosome Receptor for Myosin Va

Rab27a Is an Essential Component of Melanosome Receptor for Myosin Va

PTC1Is Required for Vacuole Inheritance and Promotes the Association of the Myosin-V Vacuole-specific Receptor Complex

Complex Formation with Ypt11p, a rab-Type Small GTPase, Is Essential To Facilitate the Function of Myo2p, a Class V Myosin, in Mitochondrial Distribution in Saccharomyces cerevisiae

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