Neuronal ELAV proteins enhance mRNA stability by a PKCalpha-dependent pathway

Proc Natl Acad Sci U S A. 2005 Aug 23;102(34):12065-70. doi: 10.1073/pnas.0504702102. Epub 2005 Aug 11.

Abstract

More than 1 in 20 human genes bear in the mRNA 3' UTR a specific motif called the adenine- and uridine-rich element (ARE), which posttranscriptionally determines its expression in response to cell environmental signals. ELAV (embryonic lethal abnormal vision) proteins are the only known ARE-binding factors that are able to stabilize the bound mRNAs, thereby positively controlling gene expression. Here, we show that in human neuroblastoma SH-SY5Y cells, neuron-specific ELAV (nELAV) proteins (HuB, HuC, and HuD) are up-regulated and redistributed by 15 min of treatment with the activators of PKC phorbol esters and bryostatin-1. PKC stimulation also induces nELAV proteins to colocalize with the translocated PKCalpha isozyme preferentially on the cytoskeleton, with a concomitant increase of nELAV threonine phosphorylation. The same treatment promotes stabilization of growth-associated protein 43 (GAP-43) mRNA, a well known nELAV target, and induces an early increase in GAP-43 protein concentration, again only in the cytoskeletal cell fraction. Genetic or pharmacological inactivation of PKCalpha abolishes nELAV protein cytoskeletal up-regulation, GAP-43 mRNA stabilization, and GAP-43 protein increase, demonstrating the primary role of this specific PKC isozyme in the cascade of nELAV recruitment. Finally, in vivo PKC activation is associated with an up-regulation of nELAV proteins in the hippocampal rat brain. These findings suggest a model for gene expression regulation by nELAV proteins through a PKCalpha-dependent pathway that is relevant for the cellular programs in which ARE-mediated control plays a pivotal role.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions / metabolism
  • Amino Acid Motifs / physiology
  • Animals
  • Blotting, Western
  • Bryostatins
  • Cell Line, Tumor
  • Cytoskeleton / metabolism
  • DNA Primers
  • ELAV Proteins / metabolism*
  • GAP-43 Protein / metabolism
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology*
  • Hippocampus / metabolism
  • Humans
  • Immunohistochemistry
  • Immunoprecipitation
  • Macrolides / pharmacology
  • Neurons / metabolism*
  • Phorbol Esters / pharmacology
  • Protein Kinase C-alpha / metabolism*
  • RNA Stability / physiology*
  • RNA, Messenger / metabolism*
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / physiology*

Substances

  • 3' Untranslated Regions
  • Bryostatins
  • DNA Primers
  • ELAV Proteins
  • GAP-43 Protein
  • Macrolides
  • Phorbol Esters
  • RNA, Messenger
  • bryostatin 1
  • Protein Kinase C-alpha