Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Differential phosphorylation of Akt1 and Akt2 by protein kinase CK2 may account for isoform specific functions.

In English

Författare

  • Cristina Girardi
  • Peter James
  • Sofia Zanin
  • Lorenzo A Pinna
  • Maria Ruzzene

Summary, in English

Akt (also known as PKB) is a survival kinase frequently up-regulated in cancer; three isoforms of Akt exist, and among them Akt1 and Akt2 are the most widely and highly expressed. They share the same structure and activation mechanism and have many overlapping functions; nevertheless isoform-specific roles and substrates have been reported, which are expected to rely on sequence diversities. In particular, a special role in differentiating Akt1 and Akt2 isoforms has been assigned to the linker region, a short segment between the PH and the catalytic domains. We have previously found that a residue in the linker region (Ser129) is directly phosphorylated by protein kinase CK2 in Akt1; the phosphorylation of the homologous residue in Akt2 (Ser131) has never been analyzed. Here we show that Akt2, endogenously or ectopically expressed in different cell lines, is not phosphorylated on Ser131 by CK2, while in vitro recombinant Akt2 is a CK2 substrate. These data support the hypothesis that in vivo a steric hindrance occurs which prevents the access to the CK2 site. Additionally, we have found that Ser129 phosphorylation is involved in the recognition of the Akt1-specific substrate palladin; this observation provides an explanation of why Akt2, lacking Ser131 phosphorylation in the linker region, has a low efficiency in targeting palladin. CK2-dependent phosphorylation is therefore a crucial event which, discriminating between Akt1 and Akt2, can account for different substrate specificity, and, more in general, for fine tuning of Akt activity in the control of isoform-dependent processes.

Publiceringsår

2014

Språk

Engelska

Sidor

1865-1874

Publikation/Tidskrift/Serie

Biochimica et Biophysica Acta

Volym

1843

Issue

9

Dokumenttyp

Artikel i tidskrift

Förlag

Elsevier

Ämne

  • Biological Sciences

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 0006-3002