Abstract
Tankyrase is an ankyrin repeat-containing poly(ADP-ribose) polymerase originally isolated as a binding partner for the telomeric protein TRF1, but recently identified as a mitogen-activated protein kinase substrate implicated in regulation of Golgi vesicle trafficking. In this study, a novel human tankyrase, designated tankyrase 2, was isolated in a yeast two-hybrid screen as a binding partner for the Src homology 2 domain-containing adaptor protein Grb14. Tankyrase 2 is a 130-kDa protein, which lacks the N-terminal histidine/proline/serine-rich region of tankyrase, but contains a corresponding ankyrin repeat region, sterile alpha motif module, and poly(ADP-ribose) polymerase homology domain. The TANKYRASE 2 gene localizes to chromosome 10q23.2 and is widely expressed, with mRNA transcripts particularly abundant in skeletal muscle and placenta. Upon subcellular fractionation, both Grb14 and tankyrase 2 associate with the low density microsome fraction, and association of these proteins in vivo can be detected by co-immunoprecipitation analysis. Deletion analyses implicate the N-terminal 110 amino acids of Grb14 and ankyrin repeats 10-19 of tankyrase 2 in mediating this interaction. This study supports a role for the tankyrases in cytoplasmic signal transduction pathways and suggests that vesicle trafficking may be involved in the subcellular localization or signaling function of Grb14.
Highlights
It is evident that protein-protein interactions play a critical role in signal transduction, mediating recruitment of signaling proteins to receptors and assembly of multiprotein signaling complexes, and directing the correct subcellular compartmentalization of such complexes and providing signal fidelity [1]
The Grb7 family is a group of related SH2 domain-containing adaptors, comprising Grb7, -10, and -14 [7]
Data supporting a positive role for mGrb10␣ in insulin, IGF-1, and platelet-derived growth factor BB-stimulated mitogenesis have recently been presented [15]
Summary
It is evident that protein-protein interactions play a critical role in signal transduction, mediating recruitment of signaling proteins to receptors and assembly of multiprotein signaling complexes, and directing the correct subcellular compartmentalization of such complexes and providing signal fidelity [1]. Identification of Grb14-interacting Proteins by the Yeast Two-hybrid Technique—In order to identify binding partners for the Grb14 adaptor protein, a human liver cDNA library in the Gal4 AD vector pACT2 was screened using a full-length Grb14 bait expressed as a Gal4 DNA-BD fusion.
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