Shugrue, C. | bioRxiv Science

bioRxiv2025

Renalase activates mitochondrial leak metabolism in response to cellular stress and to repair damage after injury

A variety of mechanisms enhance cell stress response and repair; however, the role of mitochondria in this activity is unclear. Here we show that exogenous renalase (RNLS), an intracellular flavin-dependent NADH oxidase, activates intramitochondrial RNLS activity to promote cell survival. RNLS interacts with the ATP synthase alpha and beta subunits (ATP5 and ATP5{beta}) and opens the ATP synthase c-subunit leak channel to increase complex I and II activities and protein synthesis rate. RNLS causes a selective, sustained, time-dependent increase in cellular protein synthesis without affecting cell proliferation, whereas RNLS deletion or direct inhibition of the mitochondrial leak blocks RNLS-mediated protein synthesis. Functional analysis of newly and differentially synthesized proteins over 24 hours reveals rapid changes in one-carbon metabolism and ribosomal biogenesis pathways as early as one hour after RNLS exposure. Mitochondrial injury is more severe in the RNLS KO kidney after acute stress, related to decreased protein synthesis rate and increased mitophagy. RNLS KO mice exposed to the stress of chronic cardiac pressure overload fail to develop cardiac hypertrophy, the physiological response, and die of heart failure and cardiac rupture. These data highlight the critical role RNLS has in activating mitochondrial leak metabolism to induce selective protein synthesis and protect against acute and chronic stress. HIGHLIGHTSO_LIRenalase interacts with the ATP synthase alpha and beta subunits C_LIO_LIRenalase activates mitochondrial leak metabolism C_LIO_LIRenalase and leak metabolism increase complex I and II activities C_LIO_LILeak metabolism increases protein synthesis rate C_LIO_LIRenalase protects against cell stress and organ injury C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=129 SRC="FIGDIR/small/671117v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@96ea7eorg.highwire.dtl.DTLVardef@1fcffbaorg.highwire.dtl.DTLVardef@f946cdorg.highwire.dtl.DTLVardef@197498a_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

cell biology↗

bioRxiv2022

An international scholastic network to generate LexA enhancer-trap lines for Drosophila

Conditional gene regulation in Drosophila through binary expression systems like the LexA-LexAop system provides a superb tool for investigating gene and tissue function. To increase the availability of defined LexA enhancer trap insertions, we present molecular, genetic and tissue expression studies of 301 novel Stan-X LexA enhancer traps derived from mobilization of the index SX4 line. This includes insertions into distinct loci on the X, II and III chromosomes that were not previously associated with enhancer traps or targeted LexA constructs, an insertion into ptc, and eleven insertions into natural transposons. A subset of enhancer traps was expressed in CNS neurons known to produce and secrete insulin, an essential regulator of growth, development and metabolism. Fly lines described here were generated and characterized through studies by students and teachers in an international network of genetics classes at public, independent high schools, and universities serving a diversity of students, including those underrepresented in science. Thus, a unique partnership between secondary schools and university-based programs has produced and characterized novel resources in Drosophila, establishing instructional paradigms devoted to unscripted experimental science.

genetics↗