Articles by Vishnu V. Krishnamurthy in JoVE
Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development Vishnu V. Krishnamurthy*1, Aurora J. Turgeon*2, John S. Khamo1, Payel Mondal1, Savanna R. Sharum1, Wenyan Mei2, Jing Yang2, Kai Zhang1,3,4 1Department of Biochemistry, University of Illinois at Urbana-Champaign, 2Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, 3Neuroscience Program, University of Illinois at Urbana-Champaign, 4Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign This protocol describes an optogenetic strategy to modulate mitogen-activated protein kinase (MAPK) activity during cell differentiation and Xenopus embryonic development. This method allows for the reversible activation of the MAPK signaling pathway in mammalian cell culture and in multicellular live organisms, like Xenopus embryos, with high spatial and temporal resolution.
Other articles by Vishnu V. Krishnamurthy on PubMed
Reversible Optogenetic Control of Kinase Activity During Differentiation and Embryonic Development Development (Cambridge, England). Nov, 2016 | Pubmed ID: 27697903 A limited number of signaling pathways are repeatedly used to regulate a wide variety of processes during development and differentiation. The lack of tools to manipulate signaling pathways dynamically in space and time has been a major technical challenge for biologists. Optogenetic techniques, which utilize light to control protein functions in a reversible fashion, hold promise for modulating intracellular signaling networks with high spatial and temporal resolution. Applications of optogenetics in multicellular organisms, however, have not been widely reported. Here, we create an optimized bicistronic optogenetic system using Arabidopsis thaliana cryptochrome 2 (CRY2) protein and the N-terminal domain of cryptochrome-interacting basic-helix-loop-helix (CIBN). In a proof-of-principle study, we develop an optogenetic Raf kinase that allows reversible light-controlled activation of the Raf/MEK/ERK signaling cascade. In PC12 cells, this system significantly improves light-induced cell differentiation compared with co-transfection. When applied to Xenopus embryos, this system enables blue light-dependent reversible Raf activation at any desired developmental stage in specific cell lineages. Our system offers a powerful optogenetic tool suitable for manipulation of signaling pathways with high spatial and temporal resolution in a wide range of experimental settings.
Drive the Car(go)s-New Modalities to Control Cargo Trafficking in Live Cells Frontiers in Molecular Neuroscience. 2017 | Pubmed ID: 28163671 Synaptic transmission is a fundamental molecular process underlying learning and memory. Successful synaptic transmission involves coupled interaction between electrical signals (action potentials) and chemical signals (neurotransmitters). Defective synaptic transmission has been reported in a variety of neurological disorders such as Autism and Alzheimer's disease. A large variety of macromolecules and organelles are enriched near functional synapses. Although a portion of macromolecules can be produced locally at the synapse, a large number of synaptic components especially the membrane-bound receptors and peptide neurotransmitters require active transport machinery to reach their sites of action. This spatial relocation is mediated by energy-consuming, motor protein-driven cargo trafficking. Properly regulated cargo trafficking is of fundamental importance to neuronal functions, including synaptic transmission. In this review, we discuss the molecular machinery of cargo trafficking with emphasis on new experimental strategies that enable direct modulation of cargo trafficking in live cells. These strategies promise to provide insights into a quantitative understanding of cargo trafficking, which could lead to new intervention strategies for the treatment of neurological diseases.