Identification of nuclear/nucleolar localization signal in Aplysia learning associated protein of slug with a molecular mass of 18 kDa homologous protein

Neurosci Lett. 2003 Jun 5;343(2):134-8. doi: 10.1016/s0304-3940(03)00269-6.


We isolated a learning associated protein of slug with a molecular mass of 18 kDa (LAPS18) homologue from the expressed sequence tag database of Aplysia kurodai and named it Aplysia LAPS18-like protein (ApLLP). ApLLP encodes 120 amino acids and has 57% identity with LAPS18. To examine the subcellular expression pattern of ApLLP we constructed an EGFP-tagged ApLLP fusion protein and overexpressed it in both Aplysia neurons and COS-7 cells. In contrast to the previous findings, which showed that LAPS18 is secreted by COS-7 cells, ApLLP-EGFP was localized to the nucleus, and most of it to nucleoli. Analysis of deletion mutants of ApLLP-EGFP showed that the N-terminal and the C-terminal nucleolar and nucleus localization signal sequences are important for localization to the nucleus and the nucleoli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aplysia / genetics*
  • Base Sequence
  • Behavior, Animal*
  • COS Cells
  • DNA, Complementary
  • Gene Expression
  • Green Fluorescent Proteins
  • Learning / physiology*
  • Luminescent Proteins
  • Neurons / metabolism
  • Nuclear Localization Signals / chemistry
  • Nuclear Localization Signals / genetics*
  • Polymerase Chain Reaction / methods
  • Proteins / physiology*
  • Recombinant Fusion Proteins / biosynthesis
  • Sequence Alignment
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Software
  • Subcellular Fractions / metabolism
  • Transfection
  • Viral Proteins / chemistry
  • Viral Proteins / genetics


  • DNA, Complementary
  • LAPS18 protein, Limax marginatus
  • Luminescent Proteins
  • Nuclear Localization Signals
  • Proteins
  • Recombinant Fusion Proteins
  • Viral Proteins
  • Green Fluorescent Proteins