title: A chemical-genetic strategy reveals distinct temporal requirements for SAD-1 kinase in neuronal polarization and synapse formation.
abstract: BACKGROUND
  Neurons assemble into a functional network through a sequence of developmental processes including neuronal polarization and synapse formation. In Caenorhabditis elegans, the serine/threonine SAD-1 kinase is essential for proper neuronal polarity and synaptic organization. To determine if SAD-1 activity regulates the establishment or maintenance of these neuronal structures, we examined its temporal requirements using a chemical-genetic method that allows for selective and reversible inactivation of its kinase activity in vivo.
  
  
  RESULTS
  We generated a PP1 analog-sensitive variant of SAD-1. Through temporal inhibition of SAD-1 kinase activity we show that its activity is required for the establishment of both neuronal polarity and synaptic organization. However, while SAD-1 activity is needed strictly when neurons are polarizing, the temporal requirement for SAD-1 is less stringent in synaptic organization, which can also be re-established during maintenance.
  
  
  CONCLUSIONS
  This study reports the first temporal analysis of a neural kinase activity using the chemical-genetic system. It reveals that neuronal polarity and synaptic organization have distinct temporal requirements for SAD-1.
authors.affiliation: Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada. joanne.kim@utoronto.ca
authors.forename: Joanne S M
authors.initials: JS
authors.lastname: Kim
authors.forename: Brendan N
authors.initials: BN
authors.lastname: Lilley
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.forename: Kevan M
authors.initials: KM
authors.lastname: Shokat
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Sanes
authors.forename: Mei
authors.initials: M
authors.lastname: Zhen
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009474:Neurons / Q000166:cytology* / Q000201:enzymology*; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D011720:Pyrazoles / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D013569:Synapses / Q000502:physiology
chemical_list: C479693:1-tert-butyl-3-naphthalen-1-ylmethyl-1H-pyrazolo(3,4-d)pyrimidin-4-ylemine; D047908:Intracellular Signaling Peptides and Proteins; D011720:Pyrazoles; D011743:Pyrimidines; C421165:sad-1 protein, C elegans; D017346:Protein Serine-Threonine Kinases