Creating Optimal Conditions for OPA1 isoforms by Western Blot in Muscle Tissue

Stephens, D. C.; Crabtree, A.; Beasley, H. K.; Garza-Lopez, E.; Mungai, M.; Neikirk, K.; Vang, L.; Vue, Z.; Vue, N.; Marshall, A. G.; Turner, K.; Shao, J.-q.; Murray, S. A.; Gaddy, J. A.; Wanjalla, C.; Davis, J.; Damo, S. M.; Hinton, A.

doi:10.1101/2023.05.20.541601

bioRxiv · 10.1101/2023.05.20.541601

Creating Optimal Conditions for OPA1 isoforms by Western Blot in Muscle Tissue

Stephens, D. C.·Crabtree, A.·Beasley, H. K.·Garza-Lopez, E.·Mungai, M.·Neikirk, K.·Vang, L.·Vue, Z.·Vue, N.·Marshall, A. G.·Turner, K.·Shao, J.-q.·Murray, S. A.·Gaddy, J. A.·Wanjalla, C.·Davis, J.·Damo, S. M.·Hinton, A.

View original source ↗Export metadata ↓

Abstract

OPA1 is a dynamin-related GTPase that modulates various mitochondrial functions and is involved in mitochondrial morphology. There are eight different isoforms of OPA1 in humans and five different isoforms in mice that are expressed as short or long-form isoforms. These isoforms contribute to OPA1s ability to control mitochondrial functions. However, isolating OPA1 all long and short isoforms through western blot has been a difficult task. To address this issue, we outline an optimized western blot protocol to isolate 5 different isoforms of OPA1 on the basis of different antibodies. This protocol can be used to study changes in mitochondrial structure and function. Tweetable AbstractWestern blot protocol optimization to visualize OPA1 isoforms. HighlightsO_LIProtocol for isolating OPA1 isoforms in primary skeletal muscle myoblast and myotubes C_LIO_LISteps for running isolated skeletal muscle cells from muscle tissue on a gel C_LIO_LIHow to collect samples in preparation for western blotting C_LIO_LIDetection of OPA1 isoforms C_LI Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=134 SRC="FIGDIR/small/541601v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@1dc254dorg.highwire.dtl.DTLVardef@150d3eorg.highwire.dtl.DTLVardef@186ed2org.highwire.dtl.DTLVardef@13cc3a_HPS_FORMAT_FIGEXP M_FIG C_FIG O_TBL View this table: org.highwire.dtl.DTLVardef@1c518ceorg.highwire.dtl.DTLVardef@df826borg.highwire.dtl.DTLVardef@1eb5bf8org.highwire.dtl.DTLVardef@e324e6org.highwire.dtl.DTLVardef@8baedc_HPS_FORMAT_FIGEXP M_TBL C_TBL Method SummarySamples for western blot analysis are isolated from lysed cells, loaded onto a gel, and ran using optimized conditions to better isolate OPA1 isoforms. Samples are transferred to a membrane for incubation and protein detection using OPA1 antibodies.

Source connections

Published article ↗

Explore related subjects

cell biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Stephens, D. C., Crabtree, A., Beasley, H. K., Garza-Lopez, E., Mungai, M., Neikirk, K., Vang, L., Vue, Z., Vue, N., Marshall, A. G., Turner, K., Shao, J.-q., Murray, S. A., Gaddy, J. A., Wanjalla, C., Davis, J., Damo, S. M., Hinton, A.. 2023-05-22. Creating Optimal Conditions for OPA1 isoforms by Western Blot in Muscle Tissue. https://doi.org/10.1101/2023.05.20.541601

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

High-content screening identifies FDA-approved activators of mitophagy

Mitochondrial diseases are highly heterogeneous disorders caused by defects in oxidative phosphorylation, for which only limited therapeutic options are available. The elimination of dysfunctional mitochondria via mitophagy activation is an attractive strategy to treat several mitochondrial diseases, irrespective of the underlying genetic defect. To identify pharmacological activators of this pathway, we performed a high-content screening of 1,971 FDA-approved compounds using cellular reporters of TFEB nuclear translocation and mitophagy. This screening identified 294 compounds that promoted TFEB translocation, nine of which increased the number of mitolysosomes without compromising cell viability or damaging mitochondria. Among the selected compounds, Meptazinol and Ponatinib emerged as the top-ranked mitophagy inducers in fibroblasts from patients with complex I and IV deficiency, respectively, and were prioritised for further characterisation. However, they did not rescue the bioenergetic defect, suggesting that the stimulation of mitophagy per se is not sufficient to ameliorate the OXPHOS defect in mitochondrial diseases. Overall, our findings establish a scalable platform for the identification of pharmacological activators of TFEB and identify candidate compounds for therapeutic modulation of mitophagy.

cell biology↗

bioRxiv2026

A LOV-domain photoreceptor mediates phototaxis in brown algae

Phototaxis enables motile cells to navigate light environments and plays a critical role in survival and reproduction across diverse eukaryotic lineages. This ability has evolved independently through distinct photoreceptor systems. Yet, the molecular mechanisms underlying phototaxis remain poorly understood in many major eukaryotic lineages, including stramenopiles. Here, combining functional genetics, cell biology and evolutionary analyses, we identify Helmchrome (HELM), a LOV-domain protein required for phototaxis in the brown alga Ectocarpus. HELM localizes to the posterior flagellum and is responsible for the characteristic flavin-associated fluorescence of brown algal gametes. Loss of HELM abolishes phototactic accumulation and directional orientation without affecting basal motility or fertilization, demonstrating its specific requirement for light-directed movement. Phylogenetic analyses reveal that HELM-like proteins are distributed across diverse stramenopile lineages and that their domain architecture evolved through repeated duplication of an ancestral RGS-LOV module. Our findings identify HELM as a key component of the light-sensing machinery in brown algae, provide a molecular explanation for the long-standing observation of flagellar flavin fluorescence, and reveal a distinct phototaxis system that expands the known diversity of eukaryotic light-sensing mechanisms.

cell biology↗

bioRxiv2026

A distinct chondrogenic progenitor population from human umbilical cord derived mesenchymal stromal cells for osteoarthritis therapy

Stem cell-based cartilage regeneration remains constrained by functional heterogeneity and phenotypic drift in conventional cell sources, compromising durable structural repair. Human umbilical cord-derived mesenchymal stromal cells (UC-MSCs) represent an accessible, off-the-shelf cell source; however, their broad clinical utility is hampered by cellular heterogeneity, leaving the key chondrogenic subpopulation responsible for cartilage repair unresolved. By integrating single-cell transcriptomics with functional assays, we identified and prospectively isolated a distinct, highly expandable subpopulation of skeletal stem cell-like progenitors (U-CPCs) from the human umbilical cord, establishing an extra-skeletal cell source uniquely primed for joint restoration. Single-cell transcriptomics reveal their inherent regulatory landscape, uncovering a distinct transcriptional state uniquely primed for chondrogenesis. In comparison with conventional stem cells and other tissue-derived SSC-like populations (from umbilical cord, bone marrow, adipose tissue, and dental pulp), U-CPCs exhibit a markedly enhanced chondrogenic capacity. In both a mouse cartilage injury model and a rat osteoarthritis model, the administration of U-CPCs effectively mitigates joint degeneration and drives the restoration of a structurally sound, hyaline-like matrix. Mechanistically, U-CPCs secrete extracellular vesicles enriched with microRNA Let-7a-5p, which specifically modulates DUSP7/MAPK/ERK signaling in recipient chondrocytes, thereby restoring extracellular matrix homeostasis and promoting cartilage repair. By characterizing these specialized extra-skeletal progenitors and elucidating both their intrinsic chondrogenic priming and paracrine regulation of host tissue, this study establishes U-CPCs as a robust, lineage-restricted cellular source for osteoarthritis therapy.

cell biology↗