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Signal Transduction Pathway Regulation by Signaling Mucins

Signal Transduction Pathway Regulation by Signaling Mucins. by Paul Cullen at SUNY-Buffalo. Signaling Pathways Globally Regulate Cellular Decision-Making. “MAPK” Pathways. When mis-regulated -> diseases (cancer). Signaling Pathways Are Web-Like Information Networks.

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Signal Transduction Pathway Regulation by Signaling Mucins

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  1. Signal Transduction Pathway Regulation by Signaling Mucins by Paul Cullen at SUNY-Buffalo

  2. Signaling Pathways Globally Regulate Cellular Decision-Making “MAPK” Pathways When mis-regulated -> diseases (cancer)

  3. Signaling Pathways Are Web-Like Information Networks Regulators of the TNF Signaling Pathway Genome Biology (2007) 8, R104

  4. Typical Questions What are the players in a signaling pathway? How is a signal transmitted through a pathway with high fidelity (specificity)? How are multiple signals integrated into a cohesive response (integration)?

  5. Nutrient-Dependent Foraging Behaviors Filamentous Growth Biofilm Formation T.B. Reynolds and G.R. Fink (2001) V291 p878 Required for Virulence In Fungal Pathogens

  6. The Filamentous Growth (FG) Pathway Cell-Surface Proteins: Rho GTPase/PAK: MAPK Cascade: Transcription Factor:

  7. The FG Pathway Shares Components With Other MAPK Pathways

  8. Msb2 is a Signaling Mucin that Functions in the FG Pathway Tandem Repeats Glycosylated N…(698)S Q V S D T S V S Y T T S S S S V S Q V S D T P V S Y T T S S S S V S Q V S D T P V S Y T T S S S S V S Q V S D T P V S Y T T S S S S V S Q V S D T P V S Y T T S S S S V S Q V S D T S V PS T S S S S S V S Q V S D T P V PS T S S S S S V S Q (818) …C Transmembrane Domain Rho GTPase Interaction Cullen, P.J. et al.G&D(2004)

  9. Studying Signaling Mucins in a Genetically Tractable Model May be Informative Cullen, P.J. (2007)

  10. What are Signaling Mucins Sensing?How do they become activated?

  11. An Activation Mechanism forSignaling Mucins

  12. An Activation Mechanism forSignaling Mucins Immunoblot anti-HA for Msb2-HA Immunofluorescence Msb2-GFP The Extracellular Domain of Msb2 Is Secreted

  13. Relative levels of Msb2-HA S/P by immunoblot Aspartyl Protease Yps1 Processes Msb2 Immunoblot anti-HA for Msb2-HA

  14. Extracellular Domain Is Inhibitory ß-galactosidase assays Cleavage-Dependent Activation Mechanism for Signaling Mucins

  15. The extracellular domains of signaling mucins may be inhibitory. Processing may represent a general activation mechanism for signaling mucins. Secreted/cell-associated aspartyl proteases may similarly process mammalian mucins (Liaudet-Coopman et al. 2006). Vadaie et al. J. Cell Biology (2008)

  16. Signaling Mucins and MAPK Specificity

  17. Comparative Analysis of Msb2 and Hkr1 Genes encoding the two mucins appear to be differentially regulated. The extracellular domians of both mucins are secreted. Msb2 is preferentially shed under nutrient-limiting conditions, whereas Hkr1 is not. Msb2 has a Sho1-dependent function in cell polarization that is inhibited by Hkr1. Overexpression of Hkr1 dampens the FG pathway in some mutants.

  18. Overexpression of Msb2 and Hkr1 Induce Different Outputs DNA Microarray Analysis

  19. Signaling Mucins Might Contribute to Specificity

  20. Differential Mucin Function in MAPK Pathways Pitoniak, Birkaya et al. (2009)

  21. Many Pathways Control Filamentous Growth

  22. Secretion Profiling as an Approach to Identify New MAPK Regulatory Proteins Immunoblot anti-HA Quantitation of Immunoblot >10,000 transformations and immunoblots of >10,000 samples (~700 retests) 4,750 ordered deletion mutants 5,710 genes on overexpression plasmids 510 genes that influence Msb2 secretion

  23. Secondary Screens to Focus in on Interesting Genes Genes that influence Msb2 protein secretion Genes that influence MSB2 expression Differentiate between these classes using an MSB2-lacZ reporter

  24. Comparing Expression and Secretion Profiles

  25. Many Pathways Control Filamentous Growth How are different signals integrated into a complex differentiation response?

  26. An Integrated Network of Filamentous Growth Regulation Abdullah and Cullen, 2009; Chavel et al. (IN PRESS)

  27. Polarity and Signaling How does a MAPK pathway influence polarity?

  28. Polarity and Signaling

  29. Shed Mucins and FungalPathogenesis Is Flo11, another transmembrane mucin, shed from cells? What is the function of mucin shedding in microorganisms?

  30. Flo11 is Secreted from Cells and Confers Cellular Lubrication

  31. Flo11 Is Shed from Mats Part of a Secreted Layer that Hydrates, Protects, and Regulates Mat Behaviors

  32. -model to understand signaling mucins Conclusions -general activation mechanism for signaling mucins -secreted mucins may impact microbial pathogenesis

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