The Yeast Gsk-3 Kinase Mck1 Is Necessary for Cell Wall Remodeling in Glucose-Starved and Cell Wall-Stressed Cells
Int J Mol Sci. 2025 Apr 9;26(8):3534. doi: 10.3390/ijms26083534.
ABSTRACT
The cell wall integrity (CWI) pathway is responsible for transcriptional regulation of cell wall remodeling in response to cell wall stress. How cell wall remodeling mediated by the CWI pathway is effected by inputs from other signaling pathways is not well understood. Here, we demonstrate that the Mck1 kinase cooperates with Slt2, the MAP kinase of the CWI pathway, to promote cell wall thickening in glucose-starved cells. Integrative analyses of the transcriptome, proteome and metabolic profiling indicate that Mck1 is required for the accumulation of UDP-glucose (UDPG), the substrate for β-glucan synthesis, through the activation of two regulons: the Msn2/4-dependent stress response and the Cat8-/Adr1-mediated metabolic reprogram dependent on the SNF1 complex. Analysis of the phosphoproteome suggests that similar to mammalian Gsk-3 kinases, Mck1 is involved in the regulation of cytoskeleton-dependent cellular processes, metabolism, signaling and transcription. Specifically, Mck1 may be implicated in the Snf1-dependent metabolic reprogram through PKA inhibition and SAGA (Spt-Ada-Gcn5 acetyltransferase)-mediated transcription activation, a hypothesis further underscored by the significant overlap between the Mck1- and Gcn5-activated transcriptomes. Phenotypic analysis also supports the roles of Mck1 in actin cytoskeleton-mediated exocytosis to ensure plasma membrane homeostasis and cell wall remodeling in cell wall-stressed cells. Together, these findings not only reveal the novel functions of Mck1 in metabolic reprogramming and polarized growth but also provide valuable omics resources for future studies to uncover the underlying mechanisms of Mck1 and other Gsk-3 kinases in cell growth and stress response.
PMID:40332024 | DOI:10.3390/ijms26083534
Recent advances in proteomic workflows to interrogate the SUMOylome in plants
New Phytol. 2025 May 6. doi: 10.1111/nph.70176. Online ahead of print.
ABSTRACT
Protein posttranslational modifications (PTMs) are vital for regulating protein functions. SUMOylation, a PTM essential for plant survival, involves attaching a Small Ubiquitin-like MOdifier (SUMO) to lysine residues of target proteins. SUMOylation influences stress tolerance, cell proliferation, protein stability, and gene expression. While well studied in mammals and yeast, SUMOylation studies in plants are scarce, as the identification of SUMOylated proteins and the specific modification sites is challenging. Deciphering the plant SUMOylome is essential for understanding stress response mechanisms. Advanced proteomic techniques are necessary to map these complex protein modifications. This article offers insights into the workflows employed for probing the SUMOylome. We analyze how current technological approaches have advanced our understanding of SUMOylation and highlight limitations that currently impede comprehensive mapping of SUMO signaling pathways.
PMID:40329655 | DOI:10.1111/nph.70176