Secretome translation shaped by Lysosomes and Lunapark-marked ER Junctions

This study investigates how translation of mRNAs encoding membrane and secretory proteins (“secretome mRNAs”) is spatially regulated in human cells. Using live-cell imaging, proteomics, and RNA-sequencing, we show that Lunapark (LNPK)–enriched ER junctions and lysosomes form specialized hubs that enhance secretome mRNA translation. RNA-seq was performed on U-2 OS cells with control and Lunapark knockout conditions to assess transcriptome changes. RNA-seq was performed on U-2 OS control cells and Lunapark knockout cells in biological triplicates. Total RNA was extracted, converted to cDNA, libraries prepared with modified Nextera XT protocol, and sequenced on Illumina NextSeq 2000. Differential expression analysis was performed using STAR/STARsolo alignment and DESeq2 in MATLAB.