Premium
PKB/Akt interacts with inosine‐5′ monophosphate dehydrogenase through its pleckstrin homology domain
Author(s) -
Ingley Evan,
Hemmings Brian A.
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01866-4
Subject(s) - pleckstrin homology domain , protein kinase b , biochemistry , akt1 , gtp' , biology , kinase , chemistry , phosphorylation , enzyme
The pleckstrin homology (PH) domain of the protooncogenic serine/threonine protein kinase PKB/Akt can bind phosphoinositides. A yeast‐based two‐hybrid system was employed which identified inosine‐5′ monophosphate dehydrogenase (IMPDH) type II as specifically interacting with PKB/Akts PH domain. IMPDH catalyzes the rate‐limiting step of de novo guanosine‐triphosphate (GTP) biosynthesis. Using purified fusion proteins, PKB/Akts PH domain and IMPDH associated in vitro and this association moderately activated IMPDH. Purified PKB/Akt also associated with IMPDH in vitro. We could specifically pull‐down PKB/Akt or IMPDH from mammalian cell lysates using glutathione‐ S ‐transferase (GST)–IMPDH or GST–PH domain fusion proteins, respectively. Additionally, PKB/Akt and IMPDH could be co‐immunoprecipitated from COS cell lysates and active PKB/Akt could phosphorylate IMPDH in vitro. These results implicate PKB/Akt in the regulation of GTP biosynthesis through its interaction with IMPDH, which is involved in providing the GTP pool used by signal transducing G‐proteins.