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Coordinating ERK signaling via the molecular scaffold Kinase Suppressor of Ras
Danielle Frodyma1, Beth Neilsen1, Diane Costanzo-Garvey1
1Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA.
Abstract:
Many cancers, including those of the colon, lung, and pancreas, depend upon the signaling pathways induced by mutated and constitutively active Ras. The molecular scaffolds Kinase Suppressor of Ras 1 and 2 (KSR1 and KSR2) play potent roles in promoting Ras-mediated signaling through the Raf/MEK/ERK kinase cascade. Here we summarize the canonical role of KSR in cells, including its central role as a scaffold protein for the Raf/MEK/ERK kinase cascade, its regulation of various cellular pathways mediated through different binding partners, and the phenotypic consequences of KSR1 or KSR2 genetic inactivation. Mammalian KSR proteins have a demonstrated role in cellular and organismal energy balance with implications for cancer and obesity. Targeting KSR1 in cancer using small molecule inhibitors has potential for therapy with reduced toxicity to the patient. RNAi and small molecule screens using KSR1 as a reference standard have the potential to expose and target vulnerabilities in cancer. Interestingly, although KSR1 and KSR2 are similar in structure, KSR2 has a distinct physiological role in regulating energy balance. Although KSR proteins have been studied for two decades, additional analysis is required to elucidate both the regulation of these molecular scaffolds and their potent effect on the spatial and temporal control of ERK activation in health and disease.
Insights
Kinase Suppressor of Ras (KSR) proteins are key scaffolds in Ras-mediated signaling crucial for cancer. Targeting KSR1 offers a potential therapeutic strategy with reduced toxicity, while KSR2 uniquely impacts energy balance.
Area of Science:
- Cellular Biology
- Molecular Oncology
- Signal Transduction
Background:
- Mutated Ras signaling drives many cancers, including colon, lung, and pancreas.
- Kinase Suppressor of Ras 1 and 2 (KSR1/KSR2) are critical molecular scaffolds that promote Ras-mediated signaling via the Raf/MEK/ERK kinase cascade.
Purpose of the Study:
- To summarize the canonical roles of KSR proteins in cellular signaling.
- To discuss the phenotypic consequences of KSR1/KSR2 genetic inactivation.
- To highlight the therapeutic potential of targeting KSR1 in cancer treatment.
Main Methods:
- Review of existing literature on KSR protein function.
- Analysis of KSR's role as a scaffold in the Raf/MEK/ERK pathway.
- Examination of KSR's involvement in cellular pathways and energy balance.
Main Results:
- KSR proteins act as scaffolds, regulating various cellular pathways and influencing organismal energy balance.
- KSR1 and KSR2 share structural similarities but have distinct physiological roles, with KSR2 specifically impacting energy balance.
- Genetic inactivation of KSR1 or KSR2 leads to specific phenotypic consequences.
Conclusions:
- Targeting KSR1 with small molecule inhibitors presents a promising therapeutic avenue for cancer with potentially reduced patient toxicity.
- KSR1 is a valuable reference standard for RNAi and small molecule screens to identify cancer vulnerabilities.
- Further research is needed to fully understand KSR regulation and its precise control over ERK activation in health and disease.