Dataset Information

Crystal structure of the pleckstrin homology-phosphotyrosine binding (PH-PTB) targeting region of insulin receptor substrate 1.

ABSTRACT: We have determined the crystal structure at 2.3-A resolution of an amino-terminal segment of human insulin receptor substrate 1 that encompasses its pleckstrin homology (PH) and phosphotyrosine binding (PTB) domains. Both domains adopt the canonical seven-stranded beta-sandwich PH domain fold. The domains are closely associated, with a 720-A(2) contact surface buried between them that appears to be stabilized by ionic, hydrophobic, and hydrogen bonding interactions. The nonconserved 46-residue linker between the domains is disordered. The PTB domain peptide binding site is fully exposed on the molecular surface, as is a large cationic patch at the base of the PH domain that is a likely binding site for the head groups of phosphatidylinositol phosphates. Binding assays confirm that phosphatidylinositol phosphates bind the PH domain, but not the PTB domain. Ligand binding to the PH domain does not alter PTB domain interactions, and vice versa. The structural and accompanying functional data illustrate how the two binding domains might act cooperatively to effectively increase local insulin receptor substrate 1 concentration at the membrane and transiently fix the receptor and substrate, to allow multiple phosphorylation reactions to occur during each union.

SUBMITTER: Dhe-Paganon S

PROVIDER: S-EPMC17524 | biostudies-literature | 1999 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Crystal structure of the pleckstrin homology-phosphotyrosine binding (PH-PTB) targeting region of insulin receptor substrate 1.

Dhe-Paganon S S Ottinger E A EA Nolte R T RT Eck M J MJ Shoelson S E SE

Proceedings of the National Academy of Sciences of the United States of America 19990701 15

We have determined the crystal structure at 2.3-A resolution of an amino-terminal segment of human insulin receptor substrate 1 that encompasses its pleckstrin homology (PH) and phosphotyrosine binding (PTB) domains. Both domains adopt the canonical seven-stranded beta-sandwich PH domain fold. The domains are closely associated, with a 720-A(2) contact surface buried between them that appears to be stabilized by ionic, hydrophobic, and hydrogen bonding interactions. The nonconserved 46-residue l ...[more]

PMID: 10411883

Similar Datasets

Project description:Phospholipases C (PLCs) reversibly associate with membranes to hydrolyze phosphatidylinositol-4, 5-bisphosphate (PI[4,5]P(2)) and comprise four main classes: beta, gamma, delta, and epsilon. Most eukaryotic PLCs contain a single, N-terminal pleckstrin homology (PH) domain, which is thought to play an important role in membrane targeting. The structure of a single PLC PH domain, that from PLCdelta1, has been determined; this PH domain binds PI(4,5)P(2) with high affinity and stereospecificity and has served as a paradigm for PH domain functionality. However, experimental studies demonstrate that PH domains from different PLC classes exhibit diverse modes of membrane interaction, reflecting the dissimilarity in their amino acid sequences. To elucidate the structural basis for their differential membrane-binding specificities, we modeled the three-dimensional structures of all mammalian PLC PH domains by using bioinformatic tools and calculated their biophysical properties by using continuum electrostatic approaches. Our computational analysis accounts for a large body of experimental data, provides predictions for those PH domains with unknown functions, and indicates functional roles for regions other than the canonical lipid-binding site identified in the PLCdelta1-PH structure. In particular, our calculations predict that (1). members from each of the four PLC classes exhibit strikingly different electrostatic profiles than those ordinarily observed for PH domains in general, (2). nonspecific electrostatic interactions contribute to the membrane localization of PLCdelta-, PLCgamma-, and PLCbeta-PH domains, and (3). phosphorylation regulates the interaction of PLCbeta-PH with its effectors through electrostatic repulsion. Our molecular models for PH domains from all of the PLC classes clearly demonstrate how a common structural fold can serve as a scaffold for a wide range of surface features and biophysical properties that support distinctive functional roles.

Dataset Information

Crystal structure of the pleckstrin homology-phosphotyrosine binding (PH-PTB) targeting region of insulin receptor substrate 1.

Publications

Crystal structure of the pleckstrin homology-phosphotyrosine binding (PH-PTB) targeting region of insulin receptor substrate 1.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets