Mutations in CCM3/PDCD10 result in cerebral cavernous malformations (CCMs), a major cause of cerebral hemorrhage. Despite intense interest in CCMs, very little is known about the function of CCM3. Here, we report that CCM3 is located on the Golgi apparatus, forming a complex with proteins of the germinal center kinase III (GCKIII) family and GM130, a Golgi-resident protein. Cells depleted of CCM3 show a disassembled Golgi apparatus. Furthermore, in wound-healing assays, CCM3-depleted cells cannot reorient the Golgi and centrosome properly, and demonstrate impaired migration. Golgi disassembly after either depletion of CCM3 or dissociation of CCM3 from the GM130-GCKIII complex is the result of destabilization of GCKIII proteins and dephosphorylation of their substrate, 14-3-3zeta. Significantly, the phenotype induced by CCM3 depletion can be reverted by expression of wild-type CCM3, but not by disease-associated mutants. Our findings suggest that Golgi dysfunction and the ensuing abnormalities of cell orientation and migration resulting from CCM3 mutations contribute to CCM pathogenesis.
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http://dx.doi.org/10.1242/jcs.061341 | DOI Listing |
J Lipid Res
November 2024
Department of Chemistry and Molecular Biology, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden. Electronic address:
Metabolic dysfunction-associated steatotic liver disease has emerged as a leading global cause of chronic liver disease. Our recent translational investigations have shown that the STE20-type kinases comprising the GCKIII subfamily-MST3, STK25, and MST4-associate with hepatic lipid droplets and regulate ectopic fat storage in the liver; however, the mode of action of these proteins remains to be resolved. By comparing different combinations of the silencing of MST3, STK25, and/or MST4 in immortalized human hepatocytes, we found that their single knockdown results in a similar reduction in hepatocellular lipid content and metabolic stress, without any additive or synergistic effects observed when all three kinases are simultaneously depleted.
View Article and Find Full Text PDFJ Fungi (Basel)
February 2024
Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA.
In the budding yeast , sporulation occurs during starvation of a diploid cell and results in the formation of four haploid spores forming within the mother cell ascus. Meiosis divides the genetic material that is encapsulated by the prospore membrane that grows to surround the haploid nuclei; this membrane will eventually become the plasma membrane of the haploid spore. Cellularization of the spores occurs when the prospore membrane closes to capture the haploid nucleus along with some cytoplasmic material from the mother cell, and thus, closure of the prospore membrane is the meiotic cytokinetic event.
View Article and Find Full Text PDFMol Biol Cell
September 2023
Department of Biology, University of Massachusetts Boston, Boston, MA 02125.
During exit from meiosis II, cells undergo several structural rearrangements, including disassembly of the meiosis II spindles and cytokinesis. Each of these changes is regulated to ensure that they occur at the proper time. Previous studies have demonstrated that both which encodes a STE20-family GCKIII kinase, and , which encodes a meiosis-specific activator of the Anaphase Promoting Complex, are required for both meiosis II spindle disassembly and cytokinesis in the budding yeast .
View Article and Find Full Text PDFG3 (Bethesda)
March 2023
Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria 3000, Australia.
The Germinal Center Kinase III (GckIII) pathway is a Hippo-like kinase module defined by sequential activation of Ste20 kinases Thousand and One (Tao) and GckIII, followed by nuclear dbf2-related (NDR) kinase Tricornered (Trc). We previously uncovered a role for the GckIII pathway in Drosophila melanogaster tracheal (respiratory) tube morphology. The trachea form a network of branched epithelial tubes essential for oxygen transport, and are structurally analogous to branched tubular organs in vertebrates, such as the vascular system.
View Article and Find Full Text PDFNonalcoholic fatty liver disease (NAFLD) is defined by excessive accumulation of lipid droplets within hepatocytes. The STE20-type kinases comprising the germinal center kinase III (GCKIII) subfamily - MST3, MST4, and STK25 - decorate intrahepatocellular lipid droplets and have recently emerged as critical regulators of the initiation and progression of NAFLD. While significant advancement has been made toward deciphering the role of GCKIII kinases in hepatic fat accumulation (i.
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