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Updated: May 6, 2026

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PAT1 (SLC36A1) shows nuclear localization and affects growth of smooth muscle cells from rats

Anne Jensen1, Manuel Figueiredo-Larsen, René Holm

  • 1Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; and.

American Journal of Physiology. Endocrinology and Metabolism
|November 14, 2013
PubMed

Insights

Proton-coupled amino acid transporter 1 (PAT1) is found in smooth muscle cell nuclei, not just for amino acid transport. Downregulating PAT1 in these cells promotes cellular growth, indicating a novel regulatory role.

Area of Science:

  • Cell Biology
  • Physiology
  • Molecular Biology

Background:

  • Proton-coupled amino acid transporter 1 (PAT1) facilitates amino acid transport in enterocytes.
  • PAT1 also influences cell growth and amino acid sensing in various cell types.
  • Its role in smooth muscle cells (SMCs) remains largely unexplored.

Purpose of the Study:

  • To investigate the localization and function of PAT1 in smooth muscle cells.
  • To determine if PAT1 plays a role in regulating SMC growth and proliferation.

Main Methods:

  • Immunolocalization and cellular fractionation to identify PAT1 location.
  • siRNA-mediated knockdown of PAT1 in A7r5 cells.
  • Assessment of cell growth rates following PAT1 knockdown.

Main Results:

  • PAT1 protein was detected in rat intestinal smooth muscle and A7r5 cells.
  • The majority of PAT1 localized to the nucleus in A7r5 cells and primary SMCs.
  • Knockdown of PAT1 resulted in increased cellular proliferation, suggesting a growth-inhibitory role.

Conclusions:

  • PAT1 is present in the nucleus of smooth muscle cells, distinct from its canonical transport function.
  • PAT1 appears to regulate cellular proliferation in smooth muscle cells.
  • Further research is needed to elucidate the precise nuclear functions of PAT1 in SMCs.

Keywords:
PAT1Slc36a1cellular localizationgrowth regulationsmooth muscle cells

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