Binding of the sphingolipid S1P to hTERT stabilizes telomerase at the nuclear periphery by allosterically mimicking protein phosphorylation

Shanmugam Panneer Selvam, Ryan M. De Palma, Joshua J. Oaks, Natalia Oleinik, Yuri K. Peterson, Robert Stahelin, Emmanuel Skordalakes, Suriyan Ponnusamy, Elizabeth Garrett-Mayer, Charles D. Smith, Besim Ogretmen

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

During DNA replication, the enzyme telomerase maintains the ends of chromosomes, called telomeres. Shortened telomeres trigger cell senescence, and cancer cells often have increased telomerase activity to promote their ability to proliferate indefinitely. The catalytic subunit, human telomerase reverse transcriptase (hTERT), is stabilized by phosphorylation. We found that the lysophospholipid sphingosine 1-phosphate (S1P), generated by sphingosine kinase 2 (SK2), bound hTERT at the nuclear periphery in human and mouse fibroblasts. Docking predictions and mutational analyses revealed that binding occurred between a hydroxyl group (C′3-OH) in S1P and Asp684 in hTERT. Inhibiting or depleting SK2 or mutating the S1P binding site decreased the stability of hTERT in cultured cells and promoted senescence and loss of telomere integrity. S1P binding inhibited the interaction of hTERT with makorin ring finger protein 1 (MKRN1), an E3 ubiquitin ligase that tags hTERT for degradation. Murine Lewis lung carcinoma (LLC) cells formed smaller tumors in mice lacking SK2 than in wild-type mice, and knocking down SK2 in LLC cells before implantation into mice suppressed their growth. Pharmacologically inhibiting SK2 decreased the growth of subcutaneous A549 lung cancer cell-derived xenografts in mice, and expression of wild-type hTERT, but not an S1P-binding mutant, restored tumor growth. Thus, our data suggest that S1P binding to hTERT allosterically mimicks phosphorylation, promoting telomerase stability and hence telomere maintenance, cell proliferation, and tumor growth.

Original languageEnglish (US)
Pages (from-to)ra58
JournalScience Signaling
Volume8
Issue number381
DOIs
StatePublished - Jun 16 2015

Fingerprint

Sphingolipids
Phosphorylation
Telomerase
Telomere
Proteins
Cells
Lewis Lung Carcinoma
Tumors
Cell Aging
Growth
Neoplasms
Lysophospholipids
Telomere Shortening
Ubiquitin-Protein Ligases
sphingosine 1-phosphate
human TERT protein
Cell proliferation
Fibroblasts
Chromosomes
DNA Replication

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Binding of the sphingolipid S1P to hTERT stabilizes telomerase at the nuclear periphery by allosterically mimicking protein phosphorylation. / Panneer Selvam, Shanmugam; De Palma, Ryan M.; Oaks, Joshua J.; Oleinik, Natalia; Peterson, Yuri K.; Stahelin, Robert; Skordalakes, Emmanuel; Ponnusamy, Suriyan; Garrett-Mayer, Elizabeth; Smith, Charles D.; Ogretmen, Besim.

In: Science Signaling, Vol. 8, No. 381, 16.06.2015, p. ra58.

Research output: Contribution to journalArticle

Panneer Selvam, S, De Palma, RM, Oaks, JJ, Oleinik, N, Peterson, YK, Stahelin, R, Skordalakes, E, Ponnusamy, S, Garrett-Mayer, E, Smith, CD & Ogretmen, B 2015, 'Binding of the sphingolipid S1P to hTERT stabilizes telomerase at the nuclear periphery by allosterically mimicking protein phosphorylation', Science Signaling, vol. 8, no. 381, pp. ra58. https://doi.org/10.1126/scisignal.aaa4998
Panneer Selvam, Shanmugam ; De Palma, Ryan M. ; Oaks, Joshua J. ; Oleinik, Natalia ; Peterson, Yuri K. ; Stahelin, Robert ; Skordalakes, Emmanuel ; Ponnusamy, Suriyan ; Garrett-Mayer, Elizabeth ; Smith, Charles D. ; Ogretmen, Besim. / Binding of the sphingolipid S1P to hTERT stabilizes telomerase at the nuclear periphery by allosterically mimicking protein phosphorylation. In: Science Signaling. 2015 ; Vol. 8, No. 381. pp. ra58.
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