title: Quantitative insight into models of Hedgehog signal transduction.
abstract: The Hedgehog (Hh) signaling pathway is an essential regulator of embryonic development and a key factor in carcinogenesis.(1,2) Hh, a secreted morphogen, activates intracellular signaling events via downstream effector proteins, which translate the signal to regulate target gene transcription.(3,4) In a recent publication, we quantitatively compared two commonly accepted models of Hh signal transduction.(5) Each model requires a different ratio of signaling components to be feasible. Thus, we hypothesized that knowing the steady-state ratio of core signaling components might allow us to distinguish between models. We reported vast differences in the molar concentrations of endogenous effectors of Hh signaling, with Smo present in limiting concentrations.(5) This extra view summarizes the implications of this endogenous ratio in relation to current models of Hh signaling and places our results in the context of recent work describing the involvement of guanine nucleotide binding protein Galphai and Cos2 motility.
authors.affiliation: Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, NH, USA.
authors.forename: Shohreh F
authors.initials: SF
authors.lastname: Farzan
authors.forename: Stacey K
authors.initials: SK
authors.lastname: Ogden
authors.forename: David J
authors.initials: DJ
authors.lastname: Robbins
mesh_terms: D000818:Animals; D002451:Cell Compartmentation; D004268:DNA-Binding Proteins / Q000502:physiology; D029721:Drosophila Proteins / Q000502:physiology*; D004331:Drosophila melanogaster / Q000502:physiology*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000502:physiology; D053823:Hedgehog Proteins / Q000502:physiology*; D016547:Kinesins / Q000502:physiology; D008954:Models, Biological; D046912:Multiprotein Complexes; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D000072086:Smoothened Receptor; D014157:Transcription Factors / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D053823:Hedgehog Proteins; D046912:Multiprotein Complexes; D043562:Receptors, G-Protein-Coupled; D000072086:Smoothened Receptor; D014157:Transcription Factors; C092937:ci protein, Drosophila; C107452:cos protein, Drosophila; C100664:smo protein, Drosophila; C077245:hh protein, Drosophila; D016547:Kinesins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go