Identification of Novel Molecular Targets for Pleckstrin Homology (PH) Domains Found in Oncogenes Implicated in Breast Cancer
Abstract
Plecktrin Homology (PH) domains are commonly thought of as membrane-targeting modules involved in signaling pathways that bind phosphoinositides (PPIns) with high affinity and specificity. In a recent study of S. cerevisiae, however, the vast majority demonstrated little affinity or specificity for PPIns (Yu et al, 2004). I show comparable results for selected human PH domains, with one that is high affinity and PPIns-specific, while the remainder are low to moderate affinity and promiscuous for PPIns. I outline two instances where protein-protein and protein-phosphoinositide interactions may account for specific membrane targeting observed in vivo. First, SH3BP-2 PH was identified as highly specific for the membrane lipid PtdIns(3,4)P2, and targets the host protein to the membrane. Second, FAPP1- and OSBP PH domains possess comparable affinities for Golgi- and plama membrane (PM)-enriched PPIns in vitro, although they both localize to the Golgi (not the PM) in vivo, possibly by directly interacting with the Golgi GTPase Arf1. In vitro binding studies suggest that delocalized electrostatic attraction between the basic protein and acidic phospholipids play a prominent role in these interactions. Additionally, I have solved the crystal structure of a related member of this PH domain family in complex with PPIns.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2008
- Accession Number
- ADA486604
Entities
People
- David Keleti
Organizations
- University of Pennsylvania