Project description:Aberrant signaling pathway activity is a hallmark of tumorigenesis and progression, which has guided targeted inhibitor design for over 30 years. Yet, adaptive resistance mechanisms, induced by rapid, context-specific signaling network rewiring, continue to challenge therapeutic efficacy. By leveraging progress in proteomic technologies and network-based methodologies over the past decade we developed VESPA—an algorithm designed to elucidate mechanisms of cell response and adaptation to drug perturbations—and used it to analyze 7-point phosphoproteomic time series from colorectal cancer cells treated with clinically-relevant inhibitors and control media. Interrogation of tumor-specific enzyme/substrate interactions accurately inferred kinase and phosphatase activity, based on their inferred substrate phosphorylation state, effectively accounting for signal cross-talk and sparse phosphoproteome coverage. The analysis elucidated time-dependent signaling pathway response to each drug perturbation and, more importantly, cell adaptive response and rewiring that was experimentally confirmed by CRISPRko assays, suggesting broad applicability to cancer and other diseases.
Project description:Auxin canalization is a self-organizing process that governs the flexible formation of vasculature by reinforcing the formation of auxin transport channels. A key prerequisite is the feedback between auxin signaling and directional auxin transport, mediated by PIN transporters. Despite the developmental importance of canalization, the molecular components linking auxin perception to the regulation of PIN auxin transporters remain poorly understood. We have identified TOW as a novel and essential component of auxin canalization that connects intracellular auxin signaling with cell surface auxin perception. TOW acts downstream of the TIR1/AFB–Aux/IAA–WRKY23 transcriptional auxin signaling cascade. tow mutants show pronounced defects in tissue regeneration and de novo vascular formation, accompanied by impaired establishment of polarized, PIN-expressing auxin transport channels. At the cellular level, tow mutants exhibit disrupted auxin-induced PIN polarization and altered PIN endocytic trafficking dynamics. To further explore whether TOW modulates PIN phosphorylation, we performed a phosphoproteomic analysis of 5-day-old Col-0, tow mutants, and 35S::TOW-GFP seedlings. This study provides the first global phosphoproteomic profiling of TOW-dependent regulation of PIN phosphorylation.
Project description:AMP-activated protein kinase (AMPK) is a key regulator of cellular energy homeostasis. Although AMPK has been studied extensively in cellular processes, understanding of its substrates and downstream functional network, and their contributions to cell fate and disease development, remains incomplete. To elucidate the AMPK-dependent signaling pathways, we performed global quantitative phosphoproteomic analysis using wild-type and AMPK1/2-double knockout cells and discovered 160 AMPK-dependent phosphorylation sites.
Project description:To elucidate the mechanism of neuronal activation, we conducted a global quantitative phosphoproteomic analysis of hypothalamic neurons treated with Raptin or PBS. By COG analysis of the differentially expressed phosphorylation protein, we found obvious alterations of transport and catabolism, as well as cell motility. By conducting a KEGG analysis using phosphoproteomic data, we identified the PI3K-AKT pathway.
Project description:During aging, senescent cells accumulate in bone marrow and secrete the dysfunctional factors, termed senescence associated secretory phenotype (SASP), which is implied to regulate bone metabolism. To identify the key SASP factors in bone marrow that influence skeletal aging, we analyzed the dysregulated factors in the bone marrow supernatant from young and aged rat through mass spectrometry. In another hand, BMSCs treated with rGCA, transfection of siRNA-Plxnb2 or controls were subjected to global quantitative phosphoproteomic analysis.