MERTK mediated novel site Akt phosphorylation alleviates SAV1 suppression

Nat Commun. 2019 Apr 3;10(1):1515. doi: 10.1038/s41467-019-09233-7.

Abstract

Akt plays indispensable roles in cell proliferation, survival and metabolism. Mechanisms underlying posttranslational modification-mediated Akt activation have been extensively studied yet the Akt interactome is less understood. Here, we report that SAV1, a Hippo signaling component, inhibits Akt, a function independent of its role in Hippo signaling. Binding to a proline-tyrosine motif in the Akt-PH domain, SAV1 suppresses Akt activation by blocking Akt's movement to plasma membrane. We further identify cancer-associated SAV1 mutations with impaired ability to bind Akt, leading to Akt hyperactivation. We also determine that MERTK phosphorylates Akt1-Y26, releasing SAV1 binding and allowing Akt responsiveness to canonical PI-3K pathway activation. This work provides a mechanism underlying MERTK-mediated Akt activation and survival signaling in kidney cancer. Akt activation drives oncogenesis and therapeutic resistance; this mechanism of Akt regulation by MERTK/SAV1 provides yet another complexity in an extensively studied pathway, and may yield prognostic information and therapeutic targets.

Publication types

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

MeSH terms

  • Animals
  • Carcinoma, Renal Cell / metabolism
  • Carcinoma, Renal Cell / pathology
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / physiology
  • Female
  • HEK293 Cells
  • HeLa Cells
  • Heterografts
  • Hippo Signaling Pathway
  • Humans
  • Kidney Neoplasms / metabolism
  • Kidney Neoplasms / pathology
  • Mice
  • Mice, Nude
  • Mutation
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation
  • Protein Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Signal Transduction
  • c-Mer Tyrosine Kinase / metabolism*

Substances

  • Cell Cycle Proteins
  • SAV1 protein, human
  • MERTK protein, human
  • c-Mer Tyrosine Kinase
  • Protein Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-akt