Biology subjects

Cogo, S.

Publications and source records attributed to Cogo, S..

6 recordsLinked to original sources

bioRxiv2026

Loss of catalytic activity and impaired proteostasis in guanosine nucleotide-depleted LRRK2

Coding mutations in the Leucine-rich repeat kinase 2 (LRRK2) gene represent the most common cause of familial Parkinsons disease (PD), and are frequently observed in idiopathic PD. In addition, variation around the LRRK2 locus has been shown to alter PD risk by genome-wide association studies. Disease-causing mutations cluster within the catalytic core of LRRK2 - composed of GTPase (ROC) and serine-threonine kinase domains - and lead to an increase in kinase activity, resulting in hyperphosphorylation of a subset of RAB GTPases and consequent cellular toxicity. However, the interplay between LRRK2 GTPase and kinase domains, and with the surrounding scaffold regions has remained underexplored, with implications for the prediction of on- and off-target effects associated with kinase inhibition. To address this gap, here we dissected the contributions of kinase, GTPase and scaffold domains to LRRK2 function in murine macrophages and tissues expressing endogenous levels of GTP/GDP-binding deficient Lrrk2 T1348N. Guanosine nucleotide-free Lrrk2 is devoid of both GTPase and kinase activities but maintains the scaffold shell, leading to significant reshaping of Lrrk2 interactome and engagement in novel interactions. This altered functional state leads to impaired autophagy and accumulation of enlarged lysosomes and autophagic cargo in macrophages and kidneys. Since pharmacological inhibition of LRRK2 is under clinical evaluation, our results reveal retained scaffold functions upon loss of catalytic activity that warrant careful consideration.

cell biology↗

bioRxiv2024

PAK6 promotes neuronal autophagy by regulating TFEB nuclear translocation.

Autophagy is a highly conserved homeostatic process essential for the bulk degradation of cytoplasmic components and aggregated proteins. Multiple evidence indicates that impairment of (macro)autophagy leads to neurodegeneration, such as Parkinson disease (PD). Our previous work showed that p21 activated kinase 6 (PAK6) interacts with the PD-associated leucine-rich repeat kinase (LRRK2) to promote neurite outgrowth in the mouse striatum; still the function of PAK6 in the brain is largely unknown. Here, we found that downregulation of neuronal but not glial mbt, the D. melanogaster homolog of PAK6, impairs autophagy-lysosomal function. PAK6 overexpression in cells and in C. elegans increases transcription factor EB (TFEB) nuclear translocation in a kinase activity-dependent manner. Mechanistically, PAK6 forms a complex with TFEB to regulate its nuclear localization in a manner dependent on phosphorylation of and binding to 14-3-3 proteins and phosphorylation of TFEB at S467. In line with its ability to promote neuronal autophagy, mbt downregulation exacerbates alpha-synuclein toxicity in Drosophila dopaminergic neurons. Moreover, PAK6 overexpression in the substantia nigra of mutant LRRK2 mice reduces the burden of phosphorylated alpha-synuclein in dopaminergic neurons. Altogether, our study uncovers a novel role of PAK6 as a positive regulator of autophagy via TFEB and suggests that modulating its activity may represent a way to selectively turn on autophagy in neurons, with implications for the treatment of neurodegenerative disorders.

neuroscience↗

bioRxiv2024

PAK6 rescues pathogenic LRRK2-mediated ciliogenesis and centrosomal cohesion defects in a mutation-specific manner

P21 activated kinase 6 (PAK6) is a serine-threonine kinase with physiological expression enriched in the brain and overexpressed in a number of human tumors. While the role of PAK6 in cancer cells has been extensively investigated, the physiological function of the kinase in the context of brain cells is poorly understood. Our previous work uncovered a link between PAK6 and the Parkinsons disease (PD)-associated kinase LRRK2, with PAK6 controlling LRRK2 activity and subcellular localization via phosphorylation of 14-3-3 proteins. Here, to gain more insights into PAK6 physiological function, we performed protein-protein interaction arrays and identified a subgroup of PAK6 binders related to ciliogenesis. We confirmed that endogenous PAK6 localizes at both the centrosome and the cilium, and positively regulates ciliogenesis not only in tumor cells but also in neurons and astrocytes. Strikingly, PAK6 rescues ciliogenesis and centrosomal cohesion defects associated with the G2019S but not the R1441C LRRK2 PD mutation. Since PAK6 binds LRRK2 via its GTPase/Roc-COR domain and the R1441C mutation is located in the Roc domain, we used microscale thermophoresis and AlphaFold2-based computational analysis to demonstrate that PD mutations in LRRK2 affecting the Roc-COR structure substantially decrease PAK6 affinity, providing a rationale for the differential protective effect of PAK6 toward the distinct forms of mutant LRRK2. Altogether, our study discloses a novel role of PAK6 in ciliogenesis and points to PAK6 as the first LRRK2 modifier with PD mutation-specificity.

neuroscience↗

bioRxiv2021

The activities of LRRK2 and GCase are positively correlated in clinical biospecimens and experimental models of Parkinson's disease

LRRK2 is a kinase involved in different cellular functions, including autophagy, endolysosomal pathways and vesicle trafficking. Mutations in LRRK2 cause autosomal dominant forms of Parkinsons disease (PD). Heterozygous mutations in GBA1, the gene encoding the lysosomal enzyme glucocerebrosidase (GCase), are the most common genetic risk factors for PD. Moreover, GCase function is altered in idiopathic PD and in other genetic forms of the disease. Recent work suggests that LRRK2 kinase activity can regulate GCase function. However, both a positive and a negative correlation have been described. To gain insights into the impact of LRRK2 on GCase, we investigated GCase levels and activity in LRRK2 G2019S knockin mice, in clinical biospecimens from PD patients carrying this mutation and in patient-derived cellular models. In these models we found a positive correlation between the activities of LRRK2 and GCase, which was further confirmed in cell lines with genetic and pharmacological manipulation of LRRK2 kinase activity. Overall, our study indicates that LRRK2 kinase activity affects both the levels and the catalytic activity of GCase.

neuroscience↗

bioRxiv2021

DOPAL initiates αSynuclein-mediated impaired proteostasis in neuronal projections leading to enhanced vulnerability in Parkinson's disease.

Dopamine dyshomeostasis has been acknowledged to be among the determinants of nigrostriatal neuron degeneration in Parkinsons disease (PD). Several studies in experimental models and postmortem PD patients underlined increasing levels of the aldehydic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL), which is highly reactive towards proteins. DOPAL has been shown to covalently modify the presynaptic protein Synuclein (Syn), whose misfolding and aggregation represent a major trait of PD pathology, triggering Syn oligomerization in dopaminergic neurons. Here, we demonstrated that DOPAL elicits Syn neuronal accumulation and hampers Syn clearance at synapses and the soma. By combining cellular and in vivo models, we provided evidence that DOPAL-induced Syn buildup lessens neuronal resilience, compromises synaptic integrity, and overwhelms protein quality control pathways, specifically at neuronal projections. The resulting progressive decline of neuronal homeostasis leads to dopaminergic neuron loss and motor impairment, corroborating the Syn-DOPAL interplay as an early event in PD neurodegeneration.

neuroscience↗

bioRxiv2020

PKA-mediated phosphorylation of SPG11/spatacsin regulates binding with a subset of 14-3-3 proteins

Mutations in SPG11, encoding spatacsin, constitute the major cause of autosomal recessive Hereditary Spastic Paraplegia (HSP) with thinning of the corpus callosum. Previous studies showed that spatacsin orchestrates cellular traffic events through the formation of a coat-like complex and its loss of function results in lysosomal and axonal transport impairments. However, the upstream mechanisms that regulate spatacsin trafficking are unknown. Here, using proteomics and CRISPR/Cas9-mediated tagging of endogenous spatacsin, we identified a subset of 14-3-3 proteins as physiological interactors of spatacsin. The interaction is modulated by Protein Kinase A (PKA)-dependent phosphorylation of spatacsin at Ser1955, which initiates spatacsin trafficking from the plasma membrane to the intracellular space. Our study provides novel insight in understanding spatacsin physio-pathological roles with mechanistic dissection of its associated pathways.

cell biology↗