Search bioRxiv⌕ Search

Biology subjects

Rozeveld, C. N.

Publications and source records attributed to Rozeveld, C. N..

2 recordsLinked to original sources

Lysosomal lipid metabolism promotes tumor cell invasion through local energetics and membrane lipid remodeling

Metabolic vulnerabilities in cancer have been targeted primarily to suppress tumor growth, but less is known about the metabolic requirements for tumor cell invasion. Here we report that lipid catabolism by cytosolic and lysosomal lipases supports pancreatic cancer cell invasion through both overlapping and distinct functional and metabolic mechanisms. Lysosomal acid lipase (LAL)-dependent lipid droplet catabolism promotes invadopodia formation and stabilization, enabling extracellular matrix degradation. In addition to modulating cellular energetics, lipidomics revealed that lipid droplet catabolism regulates cholesterol and membrane phospholipid levels. Using spatially resolved biosensors and cholesterol imaging, we found that lysosomal lipid catabolism occurs at invadopodia and sustains local ATP and membrane cholesterol. These findings identify spatially organized lipid catabolism as a mechanism that couples local energetics and membrane remodeling during the earliest steps of pancreatic cancer cell invasion.

cell biology↗

cAMP promotes acute lysosome biogenesis through TFEB nuclear import-export dynamics.

Cyclic adenosine monophosphate (cAMP) signaling is a major stimulus for lipid and glucose catabolism, yet catabolic processes like these can also coordinate with lysosome-dependent degradation. However, the impact of cAMP signaling on lysosomal dynamics remains unclear. Transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, is regulated by stimulus-dependent nuclear-cytoplasmic shuttling through a variety of phosphorylation events. Here, we find that elevating intracellular cAMP with forskolin and IBMX induces rapid nuclear import of TFEB-GFP within 30 minutes and coincides with a transient upregulation of TFEB target lysosome genes. By 8 hours, TFEB returns to the cytoplasm, accompanied by transcriptional downregulation. Inhibition of cAMP-dependent protein kinase A (PKA) using H89 did not block nuclear import but unexpectedly caused sustained nuclear accumulation, indicating that PKA promotes TFEB nuclear export. Consistent with this, phosphoproteomic profiling revealed increased phosphorylation of a PKA-consensus motif (RRxS) during the export phase. These findings suggest that cAMP-PKA signaling plays a novel role in temporally "tuning" lysosomal gene expression by regulating TFEB nuclear-cytoplasmic shuttling. SummaryThis study reveals that cAMP signaling dynamically regulates TFEB subcellular localization, promoting transient, calcium-dependent nuclear import as well as downstream, PKA-dependent export and phosphorylation at serines 466/467. These findings uncover a novel mechanism by which cAMP stimulation fine-tunes lysosomal gene expression by regulating TFEB nuclear import and export.

cell biology↗