Cytoskeleton (Hoboken, N.J.)最新文献

This review examines the diverse functions of dyneins, a family of motor proteins involved in intracellular transport processes, the maintenance of cell polarity, and critical signaling pathways essential for cell cycle progression. Dyneins' significant impact on critical cellular functions is mediated through their interactions with an array of organelles, including centrosomes, chromosomes, and endosomes. Dyneins also influence autophagy and immune evasion within the complex environment of cancer. This review underscores the significance of dyneins as an avenue of exploration for comprehending the intricate mechanisms that underpin cancer.

The dynamic interaction between actin filaments (AFs) and microtubules (MTs) plays a crucial role in regulating key developmental and physiological processes in plant cells, particularly in the formation of specialized cell types with distinct shapes and functions, such as pollen tubes, trichomes, and leaf epidermal cells. These cytoskeletal components are organized into specialized structures, and their coordination is tightly regulated by molecular mechanisms, including ROP signaling pathways that control actin- and microtubule-binding proteins. Additionally, bifunctional proteins such as kinesins and myosins, which interact with both AFs and MTs, further facilitate the coordination of cytoskeletal activities, thus regulating cell morphology. Recent advances in understanding of stomatal development (Arabidopsis and maize), moss protonemal cells, and xylem differentiation have provided novel mechanistic insights into cytoskeletal crosstalk. This review, based on recent discoveries, focuses on the role of actin-microtubule interactions in the formation of new cell types, vesicular transport, and cell division. Furthermore, we highlight the molecular mechanisms that govern these interactions and propose future research directions in this field.

The plant cell wall, a rigid structural layer that surrounds each plant cell, is critical for regulating and controlling cell growth. Microtubules play a role in the production of cell walls by regulating the transport and deposition of cell wall components in a spatial and temporal manner. The dynamic behavior of microtubules and their anchoring to the plasma membrane are factors that contribute to the achievement of production of the cell wall and growth of the cell. This mini review provides an overview of the plant cell wall and its dynamic interactions with microtubules. It emphasizes the role of specific proteins that mediate these interactions, supported by experimental evidence from mutant studies.

Microtubules (MTs) are essential cytoskeletal elements in all eukaryotes, playing critical roles in cell shape, intercellular organization, cell division, and cell motility. The organization of the MT network has undergone significant changes throughout plant evolution. Some MT structures, such as the preprophase band and phragmoplast, are innovations in plant lineages, while others, including the centriole and flagellum, have been lost over time. Bryophytes, consisting of mosses, liverworts, and hornworts, are the earliest land plants and occupy a key phylogenetic position in the evolution of MT organization. In the past two decades, advances in genomics, genetics, and cell imaging technologies have significantly enhanced our understanding of MT organization and function. Two representative species, Physcomitrium patens (moss) and Marchantia polymorph (liverwort), have become established model organisms, and new models for hornworts are emerging. In this review, we summarize the current knowledge of the MT cytoskeleton, drawing from early electron microscopy studies and recent advances in these emerging models. Our aim is to provide a comprehensive overview of the major MT array types and key factors involved in MT organization in bryophytes, offering insights into MT adaptation during plant evolution.

Protozoan parasites cause life-threatening infections in both humans and animals, including agriculturally significant livestock. Available treatments are typically narrow spectrum and are complicated by drug toxicity and the development of resistant parasites. Protozoan tubulin is an attractive target for the development of broad-spectrum antimitotic agents. The Medicines for Malaria Pathogen Box compound MMV676477 was previously shown to inhibit replication of kinetoplastid parasites, such as Leishmania amazonensis and Trypanosoma brucei, and the apicomplexan parasite Plasmodium falciparum by selectively stabilizing protozoan microtubules. In this report, we show that MMV676477 inhibits intracellular growth of the human apicomplexan pathogen Toxoplasma gondii with an EC₅₀ value of ~50 nM. MMV676477 does not stabilize vertebrate microtubules or cause other toxic effects in human fibroblasts. The availability of tools for genetic studies makes Toxoplasma a useful model for studies of the cytoskeleton. We conducted a forward genetics screen for MMV676477 resistance, anticipating that missense mutations would delineate the binding site on protozoan tubulin. Unfortunately, we were unable to use genetics to dissect target interactions because no resistant parasites emerged. This outcome suggests that future drugs based on the MMV676477 scaffold would be less likely to be undermined by the emergence of drug resistance.

Lateral root (LR) organogenesis is regulated by cellular flux of auxin within pericycle cells, which depends on the membrane distribution and polar localization of auxin carrier proteins. The correct distribution of auxin carrier proteins relies on the intracellular trafficking of these proteins aided by filamentous actin as a track. However, the precise role of actin in lateral root development is still elusive. Here, using vegetative class actin isovariant mutants, we revealed that loss of actin isovariant ACT8 led to increased lateral root formation. The distribution of auxin within pericycle cells was altered in act8 mutant, primarily due to the altered distribution of AUX1 and PIN7. Interestingly, incorporation of act2 mutant in act8 background (act2act8) effectively nullified the LR phenotype observed in act8 mutant, indicating that ACT2 plays an important role in LR development. To explore further, we investigated the possibility that the act8 mutant's LR phenotype and cellular auxin distribution resulted from ACT2 overexpression. Consistent with the idea, enhanced lateral root formation, altered AUX1, PIN7 expression, and auxin distribution in pericycle cells were observed in ACT2 overexpression lines. Collectively, these results suggest that actin isovariant ACT2 but not ACT8 plays a pivotal role in regulating source-to-sink auxin distribution during lateral root organogenesis.