Identification and characterization of two novel splice forms of GRIP1 in the rat brain

J Neurochem. 2006 May;97(3):884-98. doi: 10.1111/j.1471-4159.2006.03795.x. Epub 2006 Mar 15.

Abstract

We cloned two novel alternatively-spliced mRNA isoforms of glutamate receptor interacting protein 1 (GRIP1) which we named GRIP1d and GRIP1e 4-7. GRIP1d is a 135 kDa, 7-PDZ-domain variant of GRIP1, containing the 12 amino acid C-terminus originally described for the 4-PDZ-domain GRIP1c 4-7. GRIP1e 4-7 is a 75 kDa 4-PDZ-domain variant of GRIP1, containing the 12 amino acid C-terminus originally described for the 7-PDZ-domain GRIP1a/b. Northern blots indicated that GRIP1d mRNA is 5.1 kb long and abundant in brain. An antibody to the C-terminus of the 75 kDa GRIP1c 4-7 also recognized an abundant 135 kDa protein, consistent with the predicted size of GRIP1d. Similarly, an antibody to the C-terminus of the 135 kDa GRIP1a/b also recognized a low abundance 75 kDa protein, consistent with the predicted size of GRIP1e 4-7. Immunocytochemistry of hippocampal cultures and intact brain using these antibodies showed that (i) these isoforms are present in both GABAergic and glutamatergic synapses, and (ii) the isoforms co-localize in individual synapses. While GRIP1a/b isoforms are abundant in interneurons and highly concentrated in GABAergic presynaptic terminals, the isoforms recognized by the antibody to the C-terminus common to GRIP1c 4-7 and GRIP1d are much less abundant in interneurons and preferentially concentrate at the postsynaptic complex.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Alternative Splicing / genetics*
  • Amino Acid Sequence
  • Animals
  • Blotting, Northern / methods
  • Brain / cytology
  • Brain / metabolism*
  • Brain / ultrastructure
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism*
  • Cells, Cultured
  • Cloning, Molecular / methods
  • Disks Large Homolog 4 Protein
  • Embryo, Mammalian
  • Glutamate Decarboxylase / metabolism
  • Hippocampus / cytology
  • Immunohistochemistry / methods
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Membrane Proteins / metabolism
  • Microscopy, Immunoelectron / methods
  • Molecular Weight
  • Nerve Tissue Proteins / genetics*
  • Nerve Tissue Proteins / metabolism*
  • Neurons / cytology
  • Neurons / metabolism
  • Oligonucleotide Array Sequence Analysis / methods
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sequence Alignment / methods
  • Synapses / metabolism
  • Synapses / ultrastructure
  • Vesicular Glutamate Transport Protein 1 / metabolism

Substances

  • Carrier Proteins
  • Disks Large Homolog 4 Protein
  • Dlg4 protein, rat
  • Grip1 protein, rat
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • Protein Isoforms
  • Vesicular Glutamate Transport Protein 1
  • Glutamate Decarboxylase