bims-nocaut 2025-03-30 papers

Sci Adv. 2025 Mar 28. 11(13): eadt3311

Mycobacterium tuberculosis phagosome Ca2+ leakage triggers multimembrane ATG8/LC3 lipidation to restrict damage in human macrophages.

Di Chen, Antony Fearns, Maximiliano G Gutierrez.

The role of canonical autophagy in controlling Mycobacterium tuberculosis (Mtb), referred to as xenophagy, is understood to involve targeting Mtb to autophagosomes, which subsequently fuse with lysosomes for degradation. Here, we found that Ca2+ leakage after Mtb phagosome damage in human macrophages is the signal that triggers autophagy-related protein 8/microtubule-associated proteins 1A/1B light chain 3 (ATG8/LC3) lipidation. Unexpectedly, ATG8/LC3 lipidation did not target Mtb to lysosomes, excluding the canonical xenophagy. Upon Mtb phagosome damage, the Ca2+ leakage-dependent ATG8/LC3 lipidation occurred on multiple membranes instead of single or double membranes excluding the noncanonical autophagy pathways. Mechanistically, Ca2+ leakage from the phagosome triggered the recruitment of the V-ATPase-ATG16L1 complex independently of FIP200, ATG13, and proton gradient disruption. Furthermore, the Ca2+ leakage-dependent ATG8/LC3 lipidation limited Mtb phagosome damage and restricted Mtb replication. Together, we uncovered Ca2+ leakage as the key signal that triggers ATG8/LC3 lipidation on multiple membranes to mitigate Mtb phagosome damage.

DOI: https://doi.org/10.1126/sciadv.adt3311

Autophagy. 2025 Mar 27. 1-5

Keeping your endosymbiont under control: the enigmatic plastid membrane ATG8ylation in Apicomplexa parasites.

Sébastien Besteiro.

ATG8ylation of membranes has been increasingly reported over the last few years, in various configurations and across different eukaryotic models. While the unconventional conjugation of ATG8 to the outermost membrane of the plastid in apicomplexan parasites was first observed over a decade ago, it is often overlooked in literature reviews focusing on the ATG8ylation of non-autophagosomal membranes. Here, I provide a brief overview of the current knowledge on plastid ATG8ylation in these parasites and discuss a possible parallel between the evolutionary origin of this plastid and other ATG8ylation processes, such as LC3-associated phagocytosis.

Keywords: ATG8ylation; Apicomplexa; apicoplast; evolution; organelle division

DOI: https://doi.org/10.1080/15548627.2025.2483445

Autophagy. 2025 Mar 26.

ATG16L1 WD domain and linker regulates lipid trafficking to maintain plasma membrane integrity to limit influenza virus infection.

Benjamin Bone, Luke Griffith, Matthew Jefferson, Yohei Yamauchi, Thomas Wileman, Penny P Powell.

The non-canonical functions of autophagy protein ATG16L1 are dependent on a C-terminal WD domain. Recent studies show that the WD domain is required for conjugation of LC3 to single membranes during endocytosis and phagocytosis, where it is thought to promote fusion with lysosomes. Studies in cells lacking the WD domain suggest additional roles in the regulation of cytokine receptor recycling and plasma membrane repair. The WD domain also protects mice against lethal influenza virus in vivo. Here, analysis of mice lacking the WD domain (ΔWD) shows enrichment of cholesterol in brain tissue suggesting a role for the WD domain in cholesterol transport. Brain tissue and cells from ΔWD mice showed reduced cholesterol and phosphatidylserine (PS) in the plasma membrane. Cells from ΔWD mice also showed an intracellular accumulation of cholesterol predominantly in late endosomes. Infection studies using IAV suggest that the loss of cholesterol and PS from the plasma membrane in cells from ΔWD mice results in increased endocytosis and nuclear delivery of IAV, as well as increased Ifnb/Ifnβ and Isg15 gene expression. Upregulation of Il6, Ifnb and Isg15 mRNA were observed in "ex vivo" precision cut lung slices from ΔWD mice both at rest and in response to IAV infection. Overall, we present evidence that regulation of lipid transport by the WD domain of ATG16L1 May have downstream implications in attenuating viral infection and limiting lethal cytokine signaling.

Keywords: ATG16L1 WD domain; cholesterol, cytokine storm; influenza virus; interferon, non-canonical autophagy

DOI: https://doi.org/10.1080/15548627.2025.2482516

Front Cell Dev Biol. 2025 ;13 1559504

Lysosomes' fallback strategies: more than just survival or death.

Quan Wang, Ruolin Wang, Haihui Hu, Xiaoqing Huo, Fulong Wang.

Lysosomes are heterogeneous, acidic organelles whose proper functionality is critically dependent on maintaining the integrity of their membranes and the acidity within their lumen. When subjected to stress, the lysosomal membrane can become permeabilized, posing a significant risk to the organelle's survival and necessitating prompt repair. Although numerous mechanisms for lysosomal repair have been identified in recent years, the progression of lysosome-related diseases is more closely linked to the organelle's alternative strategies when repair mechanisms fail, particularly in the contexts of aging and pathogen infection. This review explores lysosomal responses to damage, including the secretion of lysosomal contents and the interactions with lysosome-associated organelles in the endolysosomal system. Furthermore, it examines the role of organelles outside this system, such as the endoplasmic reticulum (ER) and Golgi apparatus, as auxiliary organelles of the endolysosomal system. These alternative strategies are crucial to understanding disease progression. For instance, the secretion and spread of misfolded proteins play key roles in neurodegenerative disease advancement, while pathogen escape via lysosomal secretion and lysosomotropic drug expulsion underlie cancer treatment resistance. Reexamining these lysosomal fallback strategies could provide new perspectives on lysosomal biology and their contribution to disease progression.

Keywords: autophagy; endoplasmic reticulum; exosome; golgi apparatus; lysosomal damage; secretion

DOI: https://doi.org/10.3389/fcell.2025.1559504