title: Phospholipase C-η2 is required for retinoic acid-stimulated neurite growth.
abstract: Phospholipase C-η2 is a recently identified phospholipase C (PLC) implicated in the regulation of neuronal differentiation/maturation. PLCη2 activity is triggered by intracellular calcium mobilization and likely serves to amplify Ca²⁺ signals by stimulating further Ca²⁺ release from Ins(1,4,5)P₃-sensitive stores. The role of PLCη2 in neuritogenesis was assessed during retinoic acid (RA)-induced Neuro2A cell differentiation. PLCη2 expression increased two-fold during a 4-day differentiation period. Stable expression of PLCη2-targetted shRNA led to a decrease in the number of differentiated cells and total length of neurites following RA-treatment. Furthermore, RA response element activation was perturbed by PLCη2 knockdown. Using a bacterial two-hybrid screen, we identified LIM domain kinase 1 (LIMK1) as a putative interaction partner of PLCη2. Immunostaining of PLCη2 revealed significant co-localization with LIMK1 in the nucleus and growing neurites in Neuro2A cells. RA-induced phosphorylation of LIMK1 and cAMP-responsive element-binding protein was reduced in PLCη2 knock-down cells. The phosphoinositide-binding properties of the PLCη2 PH domain, assessed using a FRET-based assay, revealed this domain to possess a high affinity toward PtdIns(3,4,5)P₃. Immunostaining of PLCη2 together with PtdIns(3,4,5)P₃ in the Neuro2A cells revealed a high degree of co-localization, indicating that PtdIns(3,4,5)P₃ levels in cellular compartments are likely to be important for the spatial control of PLCη2 signaling.
authors.affiliation: School of Medicine, Medical and Biological Sciences Building, North Haugh, University of St Andrews, St Andrews, Fife, UK.
authors.forename: Petra
authors.initials: P
authors.lastname: Popovics
authors.forename: Alexander
authors.initials: A
authors.lastname: Gray
authors.forename: Mohammed
authors.initials: M
authors.lastname: Arastoo
authors.forename: Deana K
authors.initials: DK
authors.lastname: Finelli
authors.forename: Audrey J L
authors.initials: AJ
authors.lastname: Tan
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Stewart
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D054461:Lim Kinases / Q000378:metabolism; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D054801:Phosphoinositide Phospholipase C / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D014212:Tretinoin; D054461:Lim Kinases; C515893:Limk1 protein, mouse; D054801:Phosphoinositide Phospholipase C