MYO1B in human disease: an actin-based motor linking membrane trafficking to oncogenic signaling, metastasis, and vascular aging

Figures

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  Figure 1. Domain architecture and key functional motifs of Myo1b. The N-terminal motor domain features the nucleotide-binding pocket (P-loop, Switch-I) and actin-binding interface (Loops 2–4, TEDS site). The neck region stabilizes the lever arm via calmodulin-binding IQ motifs. The C-terminal tail includes the basic/acidic lipid-binding TH1 domain, the TH2 domain (implicated in F-actin binding), and the PXXP-recognizing SH3 domain.

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  Figure 2. Model of Myo1b’s role in TGN tubular carrier formation. Myosin 1b promotes post-Golgi carrier formation by regulating actin assembly and membrane remodeling of the trans-Golgi network.

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  Figure 3. Schematic of MYO1B signaling and TME modulation in HNSCC metastasis. MYO1B upregulation promotes EMT and filopodia formation by disrupting E-cadherin junctions and remodeling F-actin. Mechanistically, MYO1B drives cytoskeletal dynamics via the RhoA/ROCK-2/FAK axis (enhancing focal adhesion assembly) and promotes angiogenesis and hypoxia responses via the ERK/HIF-1α/VEGF-C axis. These pathways facilitate invasion through the extracellular matrix and modulate the tumor microenvironment, including interactions with endothelial and immune cells. Model for Myo1b function at the TGN. (a) Myo1b drives F-actin-dependent membrane tubulation and post-Golgi carrier formation. (b) Myo1b loss or inhibition disrupts TGN actin organization and impairs carrier biogenesis. (c) Myo1b excess promotes tubular precursor accumulation, consistent with scission becoming rate-limiting.