title: Protein kinase Cepsilon actin-binding site is important for neurite outgrowth during neuronal differentiation.
abstract: We have previously shown that protein kinase Cepsilon (PKCepsilon) induces neurite outgrowth via its regulatory domain and independently of its kinase activity. This study aimed at identifying mechanisms regulating PKCepsilon-mediated neurite induction. We show an increased association of PKCepsilon to the cytoskeleton during neuronal differentiation. Furthermore, neurite induction by overexpression of full-length PKCepsilon is suppressed if serum is removed from the cultures or if an actin-binding site is deleted from the protein. A peptide corresponding to the PKCepsilon actin-binding site suppresses neurite outgrowth during neuronal differentiation and outgrowth elicited by PKCepsilon overexpression. Neither serum removal, deletion of the actin-binding site, nor introduction of the peptide affects neurite induction by the isolated regulatory domain. Membrane targeting by myristoylation renders full-length PKCepsilon independent of both serum and the actin-binding site, and PKCepsilon colocalized with F-actin at the cortical cytoskeleton during neurite outgrowth. These results demonstrate that the actin-binding site is of importance for signals acting on PKCepsilon in a pathway leading to neurite outgrowth. Localization of PKCepsilon to the plasma membrane and/or the cortical cytoskeleton is conceivably important for its effect on neurite outgrowth.
authors.affiliation: Department of Laboratory Medicine, Molecular Medicine, Lund University, Malmö University Hospital, 205 02 Malmö, Sweden.
authors.forename: Ruth
authors.initials: R
authors.lastname: Zeidman
authors.forename: Ulrika
authors.initials: U
authors.lastname: Trollér
authors.forename: Arathi
authors.initials: A
authors.lastname: Raghunath
authors.forename: Sven
authors.initials: S
authors.lastname: Påhlman
authors.forename: Christer
authors.initials: C
authors.lastname: Larsson
mesh_terms: D000199:Actins / Q000378:metabolism*; D001665:Binding Sites; D002454:Cell Differentiation / Q000502:physiology; D003599:Cytoskeleton / Q000378:metabolism; D006801:Humans; D019044:Image Cytometry; D007527:Isoenzymes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D016501:Neurites / Q000502:physiology*; D009447:Neuroblastoma; D011487:Protein Conformation; D011493:Protein Kinase C / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000199:Actins; D007527:Isoenzymes; D011993:Recombinant Fusion Proteins; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon