Biology subjects

Kessels, M. M.

Publications and source records attributed to Kessels, M. M..

4 recordsLinked to original sources

bioRxiv2021

Post-stroke dendritic arbor regrowth - a cortical repair process requiring the actin nucleator Cobl

Ischemic stroke is a major cause of death and long-term disability. We demonstrate that middle cerebral artery occlusion in mice leads to a strong decline in dendritic arborization of penumbral neurons. These defects were subsequently repaired by an ipsilateral recovery process requiring the actin nucleator Cobl. Ischemic stroke and excitotoxicity, caused by calpain-mediated proteolysis, significantly reduced Cobl levels. In an apparently unique manner among excitotoxicity-affected proteins, this Cobl decline was rapidly restored by increased mRNA expression and Cobl then played a pivotal role in post-stroke dendritic arbor repair in peri-infarct areas. In Cobl KO mice, the dendritic repair window determined to span day 2-4 post-stroke in WT strikingly passed without any dendritic regrowth. Instead, Cobl KO penumbral neurons of the primary motor cortex continued to show the dendritic impairments caused by stroke. Our results thereby highlight a powerful post-stroke recovery process and identified causal molecular mechanisms critical during post-stroke repair.

neuroscience↗

bioRxiv2021

Spinal cord synaptic plasticity by GlyRβ release from receptor fields and syndapin-dependent uptake

Glycine receptor-mediated inhibitory neurotransmission is key for spinal cord function. Recent observations suggested that by largely elusive mechanisms also glycinergic synapses display synaptic plasticity. We here identify syndapin I as critical player. Interestingly, syndapin I cooperates but in part also competes with gephyrin. Syndapin I deficiency led to fragmentation of glycine receptor fields, more disperse receptors and increased receptor mobility. Kainate treatment highlighted syndapin Is importance even more. Our analyses unveiled that PKC-mediated S403 phosphorylation-mediated glycine receptor {beta} decoupling from gephyrin scaffolds simultaneously promoted syndapin I association. In line, kainate-treated syndapin I KO spinal cords showed even more severe receptor field fragmentation. Furthermore, syndapin I deficiency completely disrupted kainate-induced glycine receptor internalization. Together, this unveiled important mechanisms controlling the number and organization of glycine receptor fields at inhibitory postsynapses during both steady-state and kainate-induced synaptic rearrangement - principles organizing and fine-tuning synaptic efficacy of inhibitory synapses in the spinal cord.

neuroscience↗

bioRxiv2021

Molecular properties of Ankrd26 affected by mutations linked to leukemia and carcinoma formation

Derailed signaling originating from the plasma membrane is associated with many types of cancer. Different human cancers and thrombocytopenia are linked to ANKRD26 mutations. We unveil that Ankrd26 is a plasma membrane-localized protein forming nanoclusters and that Ankrd26 is critical for retinoic acid/BDNF-induced neuroblastoma differentiation. An N-terminal amphipathic structure lacking in an AML-associated Ankrd26 mutant is indispensable for membrane binding and bending by partial membrane insertion and renders Ankrd26 inactive in both gain-of-function and loss-of- function/rescue studies addressing cellular differentiation. In a papillary thyroid carcinoma-linked mutant, truncated Ankrd26 is fused with the kinase domain of the protooncogene RET. Our data show that the Ankrd26 part of this fusion mutant mediates anchoring of the RET kinase domain to the plasma membrane and self-association by the coiled coil domain of Ankrd26. Ankrd26-RET fusion led to massively increased ERK1/2 activity and RET autophosphorylation at both Y905 and Y1015, i.e. caused aberrant RET signaling. Our results highlight the importance and molecular details of Ankrd26-mediated organizational platforms for cellular differentiation and signaling pathways from the plasma membrane, which, if derailed, lead to cancer-associated pathomechanisms involving the unveiled Ankrd26 properties.

cancer biology↗

bioRxiv2021

Functional interdependence of the actin nucleator Cobl and Cobl-like in dendritic arbor development

Local actin filament formation is indispensable for development of the dendritic arbor of neurons. We show that, surprisingly, the action of single actin filament-promoting factors was insufficient for powering dendritogenesis. Instead, this process required the actin nucleator Cobl and its only evolutionary distant ancestor Cobl-like acting interdependently. This coordination between Cobl-like and Cobl was achieved by physical linkage by syndapin I. Syndapin I formed nanodomains at convex plasma membrane areas at the base of protrusive structures and interacted with three motifs in Cobl-like, one of which was Ca2+/calmodulin-regulated. Consistently, syndapin I, Cobl-likes newly identified N terminal calmodulin-binding site and the single Ca2+/calmodulin-responsive syndapin-binding motif all were critical for Cobl-likes functions. In dendritic arbor development, local Ca2+/CaM-controlled actin dynamics thus relies on regulated and physically coordinated interactions of different F-actin formation-promoting factors and only together they have the power to bring about the sophisticated neuronal morphologies required for neuronal network formation.

cell biology↗