Assembly and Activation of Dynein-Dynactin by the Cargo Adaptor Protein Hook3

Abstract

Metazoan cytoplasmic dynein moves processively along microtubules with the aid of dynactin and an adaptor protein that joins dynein and dynactin into a stable ternary complex. Here, we have examined how Hook3, a cargo adaptor involved in Golgi and endosome transport, forms a motile dynein-dynactin complex. We show that the conserved Hook domain interacts directly with the dynein light intermediate chain 1 (LIC1). By solving the crystal structure of the Hook domain and using structure-based mutagenesis, we identify two conserved surface residues that are each critical for LIC1 binding. Hook proteins with mutations in these residues fail to form a stable dynein-dynactin complex, revealing a crucial role for LIC1 in this interaction. We also identify a region of Hook3 specifically required for an allosteric activation of processive motility.Our work reveals the structural details of Hook3's interaction with dynein and offers insight into how cargo adaptors form processive dynein-dynactin motor complexes. (Maldonado-Baez et al., 2013;Szebenyi et al., 2006;Moynihan et al., 2009;Sano et al., 2007;Walenta et al., 2001). All mammalian Hook isoforms promote endosomal trafficking by forming a complex with Fused Toes (FTS) and Hook Interacting Protein (FHIP) (Xu et al., 2008).Here, we sought to understand the mechanism by which Hook3 interacts with dynein and dynactin and activates processive motility. We report the crystal structure of the Hook domain and show that this domain binds directly to the C-terminal region of LIC1. Structure-based mutagenesis studies revealed two conserved surface residues that are essential for this interaction. Abrogation of the LIC interaction renders Hook3 unable to join dynein and dynactin into a stable complex. Interestingly, while the N-terminal 239 residues of Hook3 are sufficient for forming a stable complex with dynein-dynactin, this tripartite complex is immotile; activation of motility requires a more distal coiled coil region of Hook3. This result reveals that complex assembly and the activation of motility are separable activities. Our data suggest a model for how Hook3 joins dynein and dynactin into a motile complex.

miR‐496 remedies hypoxia reoxygenation–induced H9c2 cardiomyocyte apoptosis via Hook3‐targeted PI3k/Akt/mTOR signaling pathway activation

“…It reported that Hook3, as a cargo adapter involved in Golgi and endosome transport, was mTOR regulator target. 13,15,24 Based on the above research results, we needed to explore that miR0496 regulate H/R-induced cell apoptosis via binding to Hook3 to regulate mTOR signaling pathway. Our results showed that the effects of Hook3 and miR-496 in H/R-induced cell apoptosis were so opposed that they just cancel each other out ( Figure 5).…”

IGF 1R regulates retrograde axonal transport of signalling endosomes in motor neurons

“…These results, together with the lack of changes in mitochondrial or lysosomal trafficking, suggest that IGF1R does not directly modulate the cellular levels of cytoplasmic dynein and kinesin-1, but rather works via an alternative mechanism. The Hook family of proteins has been found to play an important role in the retrograde transport of endosomes [35][36][37]. Therefore, we decided to analyse the expression levels of Hook3 in PMNs following modulation of IGF1R activity, along with two other dynein adaptors: BICD1 and BICD2.…”

Insights into LIS1 function in cargo-adapter-mediated dynein activation in vivo

“…Although the plus-end to minus-end (MTOC) relocation of dynein-dynactin is fully consistent with cargo adapter-mediated dynein activation observed in vitro (McKenney et al, 2014;Schlager et al, 2014;Olenick et al, 2016;Schroeder and Vale, 2016), we sought to further confirm that this relocation needs functional dynein. To do that, we examined the effect of a previously identified dynein loss-of-function mutation, nudA F208V .…”

“…Recently, the interaction between fungal dynein and early endosome has been found to be mediated by dynactin as well as the Fhip-Hook-Fts (FHF) complex (Walenta et al, 2001;Xu et al, 2008;Zhang et al, 2011;Bielska et al, 2014b;Zhang et al, 2014). Within the FHF complex, Hook (HookA in A. nidulans and Hok1 in U. maydis) interacts with dynein-dynactin and Fhip interacts with early endosome (Bielska et al, 2014b;Yao et al, 2014;Zhang et al, 2014;Guo et al, 2016;Schroeder and Vale, 2016). The function of dynactin and the Hook complex in early endosome transport is evolutionarily conserved (although multiple Hook proteins in mammalian cells participate in even more functions of dynein) (Yeh et al, 2012;Guo et al, 2016;Dwivedi et al, 2019;, and importantly, mammalian Hook proteins activate dynein in vitro (McKenney et al, 2014;Olenick et al, 2016;Schroeder and Vale, 2016).…”