Biology subjects

McCartney, B.

Publications and source records attributed to McCartney, B..

4 recordsLinked to original sources

bioRxiv2026

Microtubules coordinate with actin assembly and disassembly to elongate cortical actin cables

The coordination of actin filament elongation, bundling and turnover within bundled actin structures is poorly understood. Nurse cells extend bundles of actin filaments (cables) from the cortex during Drosophila oogenesis. We previously showed that cable assembly requires a developmentally-regulated microtubule (MT) network. Here we demonstrate that MTs coordinate with actin filament assembly and disassembly to promote the persistent elongation of actin cables. Disrupting the MT network caused actin cables to detach from the cortex and become free in the cytoplasm. The subsequent fate of those free cables, shrinking over time or maintaining a stable length, depended on the MT manipulation. Furthermore, maintaining cortical continuity and persistent cable elongation requires a regulated imbalance between filament assembly and disassembly. Favoring disassembly caused cable detachment and shrinkage while reducing disassembly allowed free cables to continue elongating in the cytoplasm. Our results also suggest that both filament assembly and disassembly occur at the cortical filament barbed-ends protected from excessive disassembly by Capping Protein.

cell biology↗

bioRxiv2024

Developmentally regulated actin-microtubule crosstalk in Drosophila oogenesis

Actin-microtubules (MT) interactions are essential, but how those mechanisms are orchestrated in complex developing systems is poorly understood. Here we show that actin-MT crosstalk regulates actin cable assembly and the assembly and organization of MTs in Drosophila nurse cells during oogenesis. We found that a stable MT meshwork develops concurrently with actin cable initiation and requires acetylation for its maintenance. These {gamma}-tubulin nucleated MTs are cortically tethered via Patronin and Shortstop, extend into the cytoplasm, and coalign with the elongating actin cables. The MT network promotes the cortical enrichment of the actin assembly factors Diaphanous and Enabled and loss of MTs dramatically reduced actin cable density and growth rate. We further demonstrated that actin filament assembly promotes cortical tethering of MTs and that loss of the actin filament bundler Villin/Quail results in fewer, shorter, and more highly coaligned MTs. Together, our data reveal multiple modes of coordinated actin-MT crosstalk producing actin cable-MT network synergy that is instrumental for oogenesis. SummaryThis study demonstrates actin-microtubule crosstalk in Drosophila oogenesis, revealing coregulation between actin filament assembly/bundling and microtubule nucleation/organization, highlighting the coordinated regulation of the cytoskeleton required during development.

cell biology↗

bioRxiv2020

A Diaphanous and Enabled dependent asymmetric actin cable array repositions nuclei during Drosophila oogenesis

Cells reposition their nuclei for a diversity of specialized functions through a wide variety of cytoskeletal mechanisms. To complete oogenesis, Drosophila nurse cells employ novel actin cable arrays to reposition their nuclei. During oogenesis, 15 nurse cells connected by ring canals contract to "dump" their cytoplasmic contents into the oocyte. Just prior to dumping, actin cables initiate from the nurse cell cortex and elongate toward their nuclei, pushing them away from the ring canals to prevent obstruction. How the actin cable arrays generate directional nuclear movement is not known. We found regional differences in the actin cable growth rate that are dependent on the differential localization of the actin assembly factors Enabled (Ena) and Diaphanous (Dia). Mislocalization of Ena resulted in actin cable arrays with a uniform growth rate. In the absence of growth rate asymmetry, nuclear relocation was significantly altered and cytoplasmic dumping was incomplete. This novel mechanism for nuclear repositioning relies on the regulated cortical localization of Dia and Ena producing asymmetric actin cable arrays that push the nuclei away from the ring canals, enabling successful oogenesis. Summary statementThis work demonstrates that an asymmetric actin cable array regulated by the differential localization of Diaphanous and Enabled is necessary to reposition nurse cell nuclei and complete oogenesis in Drosophila.

developmental biology↗

bioRxiv2019

Towards a real-world brain-computer interface for image retrieval

Brain decoding -- the process of inferring a persons momentary cognitive state from their brain activity -- has enormous potential in the field of human-computer interaction. In this study we propose a zero-shot EEG-to-image brain decoding approach which makes use of state-of-the-art EEG preprocessing and feature selection methods, and which maps EEG activity to biologically inspired computer vision and linguistic models. We apply this approach to solve the problem of identifying viewed images from recorded brain activity in a reliable and scalable way. We demonstrate competitive decoding accuracies across two EEG datasets, using a zero-shot learning framework more applicable to real-world image retrieval than traditional classification techniques.

neuroscience↗