Structure analyses reveal a regulated oligomerization mechanism of the PlexinD1/GIPC/myosin VI complex

Shang, Guijun; Brautigam, Chad A.; Chen, Rui; Lu, Defen; Torres-Vázquez, Jesús; Zhang, Xuewu

doi:10.7554/elife.27322

Cited by 49 publications

(90 citation statements)

References 64 publications

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“…We therefore propose that the complex stoichiometry exists as one active binding partner (monomer or dimer) per MVI molecule (Figure 8). This stoichiometry has been reported from structural studies [24,31]. Rapid mixing kinetics allowed us to probe the individual mechanistic steps and therefore propose that dimerization can occur rapidly following unfolding of MVI, with unfolding being the rate-limiting step once binding partner interaction occurs.…”

Section: Discussionsupporting

confidence: 66%

Binding partners regulate unfolding of myosin VI to activate the molecular motor

Santos

Fili

Hari-Gupta

et al. 2020

Preprint

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Myosin VI is the only minus-end actin motor and is coupled to various cellular processes ranging from endocytosis to transcription. This multipotent nature is achieved through alternative isoform splicing and interactions with a network of binding partners. How the regulation mechanism of myosin VI varies between different isoforms and binding partners remains unexplored. Here, we have compared the regulation of two myosin VI splice isoforms by two different binding partners. By combining biochemical and single-molecule approaches, we propose that myosin VI regulation follows a generic mechanism, independently of the spliced isoform and the binding partner involved. We describe how myosin VI adopts an autoinhibited backfolded state which is unfolded by binding partners. This unfolding activates the motor and can subsequently trigger dimerization. We have further expanded our study by using live single molecule imaging to investigate the impact of binding partners upon myosin VI molecular organisation and dynamics. Overall, binding partners determine myosin VI function.

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Section: Discussionsupporting

confidence: 66%

Binding partners regulate unfolding of myosin VI to activate the molecular motor

Santos

Fili

Hari-Gupta

et al. 2020

Preprint

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“…GIPC binds directly to the ABD1 . In its inactive form GIPC exists as an autoinhibited dimer, which opens up upon cargo binding to interact with the RRL motif in MYO6 . The GIPC‐MYO6 complex can assemble into linear higher order oligomers, in which GIPC binds via its C‐terminal GIPC‐homology 2 (GH2) domain to the RRL motif, which is embedded in the middle of the second α‐helix in MYO6 ABD2 1084–1128 .…”

Section: Myo6 Molecular Interactionsmentioning

confidence: 99%

“…The GIPC‐MYO6 complex can assemble into linear higher order oligomers, in which GIPC binds via its C‐terminal GIPC‐homology 2 (GH2) domain to the RRL motif, which is embedded in the middle of the second α‐helix in MYO6 ABD2 1084–1128 . The GH2 of the first GIPC molecule interacts with the two arginines (RR 1116,1117 ) of the RRL motif and an extended region to allow hydrophobic interactions . The GH2 domain of the second GIPC molecule binds to the opposite side of the MYO6 CBD covering the leucine (L 1118 ) of the RRL motif allowing the formation of five, or even longer, linear GIPC‐MYO6 oligomers.…”

Section: Myo6 Molecular Interactionsmentioning

confidence: 99%

“…Dab2, LMTK and TOM1 proteins all interact with MYO6 via ABD2, which includes the WWY motif [15,29,30]. The tail also contains two ubiquitin-binding sites, a Motif Interacting with Ubiquitin (MIU) 997-1024 and a Myosin VI Ubiquitin-Binding Domain (MyUb) 1080-1122 , which overlaps with the ABD1 1084-1128 and the lipid-binding domain 1122-1131 (PIP 2 ) [20,21,79,80]. Through the ABD1/MyUb domain MYO6 can either interact directly with adaptor proteins such as GIPC, TAX1BP1, NDP52 and optineurin [16,51,52] or indirectly via ubiquitin chains to other proteins.…”

Section: Myo6 Molecular Interactionsmentioning

confidence: 99%

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TheMYO6 interactome: selective motor‐cargo complexes for diverse cellular processes

et al. 2019

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Myosins of class VI (MYO6) are unique actin‐based motor proteins that move cargo towards the minus ends of actin filaments. As the sole myosin with this directionality, it is critically important in a number of biological processes. Indeed, loss or overexpression of MYO6 in humans is linked to a variety of pathologies including deafness, cardiomyopathy, neurodegenerative diseases as well as cancer. This myosin interacts with a wide variety of direct binding partners such as for example the selective autophagy receptors optineurin, TAX1BP1 and NDP52 and also Dab2, GIPC, TOM1 and LMTK2, which mediate distinct functions of different MYO6 isoforms along the endocytic pathway. Functional proteomics has recently been used to identify the wider MYO6 interactome including several large functionally distinct multi‐protein complexes, which highlight the importance of this myosin in regulating the actin and septin cytoskeleton. Interestingly, adaptor‐binding not only triggers cargo attachment, but also controls the inactive folded conformation and dimerisation of MYO6. Thus, the C‐terminal tail domain mediates cargo recognition and binding, but is also crucial for modulating motor activity and regulating cytoskeletal track dynamics.

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“…Over 600 million years old, Plexin-family receptors display high degrees of conservation across evolutionarily distant species for both extracellular and cytoplasmic domains (Junqueira Alves et al, 2019). Structural and biochemical investigations have identified several core domains required for Plexin signaling (Bell et al, 2011; He et al, 2009; Janssen et al, 2010, 2012; Kong et al, 2016; Liu et al, 2010; Nogi et al, 2010; Shang et al, 2017; Tong et al, 2009, 2007, 2008; Wang et al, 2012, 2013): the extracellular Sema domain, the intracellular Rac and Rho GTPase-binding sites, and the intracellular catalytic RapGAP domain (Figure 1A). Besides the Mical and CRMP (collapsin response mediator protein) pathways for certain Plexins (Alto and Terman, 2017), the current working model of Plexin signal transduction suggests that concomitant Semaphorin extracellular binding and Rac intracellular binding lead to Plexin dimerization, which subsequently activates the catalytic GAP domain to hydrolyze Rap-GTP for downstream signaling (Pascoe et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Functional divergence of Plexin B structural motifs in distinct steps ofDrosophilaolfactory circuit assembly

Guajardo

Luginbuhl

Han

et al. 2019

Preprint

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10Plexins exhibit multitudinous, evolutionarily conserved functions in the development of nervous 11 systems. However, how Plexins employ their diverse structural motifs in vivo to perform distinct 12 roles in the stepwise assembly of neural circuits is unclear. Here, we systematically mutagenized 13 65 fasciculation of olfactory receptor neurons (ORNs) and level-dependent tasks in ORN axon 66 trajectory choice and subsequent glomerular targeting (Li et al., 2018b). These findings reveal 67 that, within one system, PlexB regulates several fundamental cellular processes of neural wiring, 68 namely axon-axon interaction (fasciculation), axon guidance (trajectory choice), and synaptic 69 partner selection (glomerular targeting) ( Figure 1C). Given that this level dependence is only 70 observed in trajectory choice and glomerular targeting but not in fasciculation, it is likely that PlexB 71 signals in different ways when executing these distinct tasks. The multi-step development of the 72 fly olfactory map thus provides an excellent system for characterizing the structure-to-function 73 relationship of Plexin in vivo. 74Through systematic mutagenesis of PlexB structural motifs ( Figure 1A, B) and functional 75 interrogation in the context of fly olfactory circuit assembly ( Figure 1C), we report here the 76 differential engagement of PlexB structural motifs in distinct neurodevelopmental processes. 77From the global necessity of Sema domain to the overall expendability of GAP catalytic integrity, 78 3 as well as the involvement of GTPase-binding motifs in trajectory choice and glomerular targeting 79 but not in fasciculation, our findings link the categorical diversity of PlexB-dependent wiring 80 processes to its varied utilization of distinct signaling modules. Moreover, we identified a 81 regulatory role of PlexB cleavage in vivo and surprisingly found that the cleaved fragments can 82 functionally reconstitute for signaling. Collectively, our analysis reveals how a single molecule, 83PlexB, plays multitudinous roles in instructing cellular behaviors through the varied use of its 84 distinct structural motifs. 86 Results 87Systematic mutagenesis of PlexB structural motifs and in vivo functional assays 88To dissect the structure-to-function relationship of PlexB in the assembly of the fly olfactory map, 89we generated nine UAS transgenic lines carrying PlexB variants (described below; Figure 1B) 90 produced by site-directed mutagenesis. A V5 tag was added to the C-terminus of each variant. 91To obtain comparable expression levels, all transgenes were mutagenized from a single wild-type 92 UAS-PlexB construct (Joo et al., 2013) and integrated into the same genomic locus, ZH-attP-93 86Fb (Bischof et al., 2007). Their expression in Drosophila neurons in vivo was verified by 94Western blotting with an anti-V5 antibody (Figure 1-figure supplement 1). 95Sema Domain The extracellular Sema domain is a molecular signature of Plexins and 96 Semaphorins -the canonical Plexin ligands. It mediates binding between Plexins and ...

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Structure analyses reveal a regulated oligomerization mechanism of the PlexinD1/GIPC/myosin VI complex

Cited by 49 publications

References 64 publications

Binding partners regulate unfolding of myosin VI to activate the molecular motor

Binding partners regulate unfolding of myosin VI to activate the molecular motor

TheMYO6 interactome: selective motor‐cargo complexes for diverse cellular processes

Functional divergence of Plexin B structural motifs in distinct steps ofDrosophilaolfactory circuit assembly

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