Shp2 is dispensable in the formation and maintenance of the neuromuscular junction

Neurosignals. 2006-2007;15(2):53-63. doi: 10.1159/000094484. Epub 2006 Jul 11.

Abstract

SHP2, a protein tyrosine phosphatase with two SH2 domains, has been implicated in regulating acetylcholine receptor (AChR) gene expression and cluster formation in cultured muscle cells. To understand the role of SHP2 in neuromuscular junction (NMJ) formation in vivo, we generated mus cle-specific deficient mice by using a loxP/Cre strategy since Shp2 null mutation causes embryonic lethality. Shp2(floxed/floxed) mice were crossed with mice expressing the Cre gene under the control of the human skeletal alpha-actin (HSA) promoter. Expression of SHP2 was reduced or diminished specifically in skeletal muscles of the conditional knockout (CKO) mice. The mutant mice were viable and fertile, without apparent muscle defects. The mRNA of the AChR alpha subunit and AChR clusters in CKO mice were localized in a narrow central region surrounding the phrenic nerve primary branches, without apparent change in intensity. AChR clusters colocalized with markers of synaptic vesicles and Schwann cells, suggesting proper differentiation of presynaptic terminals and Schwann cells. In comparison with age-matched littermates, no apparent difference was observed in the size and length of AChR clusters in CKO mice. Both the frequency and amplitude of mEPPs in CKO mice were similar to those in controls, suggesting normal neurotransmission when SHP2 was deficient. These results suggest that Shp2 is not required for NMJ formation and/or maintenance.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholinesterase / metabolism
  • Animals
  • Blotting, Western / methods
  • Diaphragm / cytology
  • Diaphragm / drug effects
  • Diaphragm / physiology
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Excitatory Postsynaptic Potentials / radiation effects
  • Histocytochemistry / methods
  • In Situ Hybridization / methods
  • In Vitro Techniques
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Mice
  • Mice, Transgenic
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology
  • Neurofilament Proteins / metabolism
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / physiology*
  • Neuromuscular Junction / radiation effects
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatases / genetics
  • Protein Tyrosine Phosphatases / metabolism*
  • Receptors, Cholinergic / metabolism

Substances

  • Intracellular Signaling Peptides and Proteins
  • Neurofilament Proteins
  • Receptors, Cholinergic
  • Acetylcholinesterase
  • PTPN11 protein, human
  • Protein Tyrosine Phosphatase, Non-Receptor Type 11
  • Protein Tyrosine Phosphatases
  • Ptpn11 protein, mouse