Biology subjects

Pinho-Correia, L. M.

Publications and source records attributed to Pinho-Correia, L. M..

2 recordsLinked to original sources

bioRxiv2025

Microtubule curling as an efficient readout to uncover fundamental concepts of axonal cell biology

Nerve fibres (aka axons) are the slender, up-to-meter-long processes of nerve cells that wire nervous systems. These delicate structures must survive for an organisms lifetime, making them prime lesion sites in neurodegeneration. Their long-term maintenance requires the homeostasis of complex local cell biology upheld by motor protein-driven transport along microtubule bundles that run uninterrupted along axons. To gain an understanding of axonal homeostasis, we report and discuss here the functional loss of 105 genes from a wide range of cell biological processes using a standardised Drosophila primary neuron system. [~]40% of these gene deficiencies caused microtubule bundle disturbances referred to as microtubule-curling, which we use as an indicator of axonal atrophy. Our live imaging showed that microtubule-curling initiates in areas where axons widen, such as areas close to the soma, branch points or growth cones. In wild-type neurons, any initiated curling was contained, but it persisted as growing footprints in mutant curl-promoting conditions. Closer analyses of 20 curl-promoting conditions suggested a general classification into two groups: mutations affecting axonal physiology cause ROS-mediated microtubule-curling, whereas mutations causing motor hyperactivation or affecting microtubule-regulating proteins cause structurally induced ROS-independent curling. As will be discussed, our data provide consistent support for the previously proposed dependency cycle of local axon homeostasis model which can explain the long-standing conundrum that genes from a wide range of cell biological processes often have mutational links to the same class of inherited neurodegenerative disease.

cell biology↗

bioRxiv2021

New cell biological explanations for kinesin-linked axon degeneration

Axons are the slender, up to meter-long projections of neurons that form the biological cables wiring our bodies. Most of these delicate structures must survive for an organisms lifetime, meaning up to a century in humans. Axon maintenance requires life-sustaining motor protein-driven transport distributing materials and organelles from the distant cell body. It seems logic that impairing this transport causes systemic deprivation linking to axon degeneration. But the key steps underlying these pathological processes are little understood. To investigate mechanisms triggered by motor protein aberrations, we studied more than 40 loss- and gain-of-function conditions of motor proteins, cargo linkers or further genes involved in related processes of cellular physiology. We used one standardised Drosophila primary neuron system and focussed on the organisation of axonal microtubule bundles as an easy to assess readout reflecting axon integrity. We found that bundle disintegration into curled microtubules is caused by the losses of Dynein heavy chain and the Kif1 and Kif5 homologues Unc-104 and Kinesin heavy chain (Khc). Using point mutations of Khc and functional loss of its linker proteins, we studied which of Khcs sub-functions might link to microtubule curling. One cause was emergence of harmful reactive oxygen species through loss of Milton/Miro-mediated mitochondrial transport. In contrast, loss of the Kinesin light chain linker caused microtubule curling through an entirely different mechanism appearing to involve increased mechanical challenge to microtubule bundles through de-inhibition of Khc. The wider implications of our findings for the understanding of axon maintenance and pathology are discussed.

cell biology↗