Crystal structure of the phosphatidylinositol 3,4-bisphosphate-binding pleckstrin homology (PH) domain of tandem PH-domain-containing protein 1 (TAPP1): molecular basis of lipid specificity

Biochem J. 2001 Sep 1;358(Pt 2):287-94. doi: 10.1042/0264-6021:3580287.


Phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P(3)] and its immediate breakdown product PtdIns(3,4)P(2) function as second messengers in growth factor- and insulin-induced signalling pathways. One of the ways that these 3-phosphoinositides are known to regulate downstream signalling events is by attracting proteins that possess specific PtdIns-binding pleckstrin homology (PH) domains to the plasma membrane. Many of these proteins, such as protein kinase B, phosphoinositide-dependent kinase 1 and the dual adaptor for phosphotyrosine and 3-phosphoinositides (DAPP1) interact with both PtdIns(3,4,5)P(3) and PtdIns(3,4)P(2) with similar affinity. Recently, a new PH-domain-containing protein, termed tandem PH-domain-containing protein (TAPP) 1, was described which is the first protein reported to bind PtdIns(3,4)P(2) specifically. Here we describe the crystal structure of the PtdIns(3,4)P(2)-binding PH domain of TAPP1 at 1.4 A (1 A=0.1 nm) resolution in complex with an ordered citrate molecule. The structure is similar to the known structure of the PH domain of DAPP1 around the D-3 and D-4 inositol-phosphate-binding sites. However, a glycine residue adjacent to the D-5 inositol-phosphate-binding site in DAPP1 is substituted for a larger alanine residue in TAPP1, which also induces a conformational change in the neighbouring residues. We show that mutation of this glycine to alanine in DAPP1 converts DAPP1 into a TAPP1-like PH domain that only interacts with PtdIns(3,4)P(2), whereas the alanine to glycine mutation in TAPP1 permits the TAPP1 PH domain to interact with PtdIns(3,4,5)P(3).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Binding, Competitive
  • Blood Proteins / chemistry
  • Blood Proteins / genetics
  • Carrier Proteins / chemistry*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Citrates / metabolism
  • Crystallization
  • Fatty Acids / chemistry
  • Fatty Acids / genetics
  • Intracellular Signaling Peptides and Proteins*
  • Lipoproteins*
  • Membrane Proteins*
  • Models, Molecular
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Phosphatidylinositol Phosphates / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid


  • Adaptor Proteins, Signal Transducing
  • Blood Proteins
  • Carrier Proteins
  • Citrates
  • DAPP1 protein, human
  • Fatty Acids
  • Intracellular Signaling Peptides and Proteins
  • Lipoproteins
  • Membrane Proteins
  • PLEKHA1 protein, human
  • Phosphatidylinositol Phosphates
  • phosphatidylinositol 3,4-diphosphate

Associated data

  • PDB/1EAZ