Absence of intracellular ion channels TPC1 and TPC2 leads to mature-onset obesity in male mice, due to impaired lipid availability for thermogenesis in brown adipose tissue

Endocrinology. 2015 Mar;156(3):975-86. doi: 10.1210/en.2014-1766. Epub 2014 Dec 29.


Intracellular calcium-permeable channels have been implicated in thermogenic function of murine brown and brite/beige adipocytes, respectively transient receptor potential melastin-8 and transient receptor potential vanilloid-4. Because the endo-lysosomal two-pore channels (TPCs) have also been ascribed with metabolic functionality, we studied the effect of simultaneously knocking out TPC1 and TPC2 on body composition and energy balance in male mice fed a chow diet. Compared with wild-type mice, TPC1 and TPC2 double knockout (Tpcn1/2(-/-)) animals had a higher respiratory quotient and became obese between 6 and 9 months of age. Although food intake was unaltered, interscapular brown adipose tissue (BAT) maximal temperature and lean-mass adjusted oxygen consumption were lower in Tpcn1/2(-/-) than in wild type mice. Phosphorylated hormone-sensitive lipase expression, lipid density and expression of β-adrenergic receptors were also lower in Tpcn1/2(-/-) BAT, whereas mitochondrial respiratory chain function and uncoupling protein-1 expression remained intact. We conclude that Tpcn1/2(-/-) mice show mature-onset obesity due to reduced lipid availability and use, and a defect in β-adrenergic receptor signaling, leading to impaired thermogenic activity, in BAT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue, Brown / physiology*
  • Animals
  • Body Temperature Regulation / physiology*
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Gene Expression Regulation / physiology
  • Lipid Metabolism / genetics
  • Lipid Metabolism / physiology*
  • Male
  • Mice
  • Mice, Knockout
  • Obesity / genetics*
  • Obesity / metabolism
  • Protozoan Proteins
  • Receptors, Adrenergic, beta / physiology
  • Signal Transduction


  • Calcium Channels
  • Protozoan Proteins
  • Receptors, Adrenergic, beta
  • TPCN1 protein, mouse
  • TPCN2 protein, mouse
  • aginactin protein, Dictyostelium