Structure of the binding site for inositol phosphates in a PH domain.

Hyvönen, Marko; Macias, M. J.; Nilges, Michaël; Oschkinat, Hartmut; Saraste, Matti; Wilmanns, Matthias

doi:10.1002/j.1460-2075.1995.tb00149.x

Cited by 336 publications

(352 citation statements)

References 39 publications

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“…These results with Tec are also consistent with a previous study of Bmx that found that the E42K mutant of Bmx has reduced kinase activity in fibroblasts (33). One possible explanation for the discrepancy between Btk and Tec/Bmx is apparent from models of other Tec kinase PH domain structures (46) based on the x-ray crystal structure of the Btk PH domain (54). Specifically, the glutamic acid residue at position 41 in Btk (42 in other Tec kinases) is thought to be too far away from the inositol-binding pocket to directly interact with the inositol phosphate moiety of phosphatidylinositol-3,4,5-trisphosphate (PtdInsP3).…”

Section: The Importance Of the Ph Domain In Tec Family Kinasessupporting

confidence: 90%

Tec Kinase Signaling in T Cells Is Regulated by Phosphatidylinositol 3-Kinase and the Tec Pleckstrin Homology Domain

Yang

Ching

Tsoukas

et al. 2001

The Journal of Immunology

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Tec, the prototypical member of the Tec family of tyrosine kinases, is abundantly expressed in T cells and other hemopoietic cell types. Although the functions of Itk and Txk have recently been investigated, little is known about the role of Tec in T cells. Using antisense oligonucleotide treatment to deplete Tec protein from primary T cells, we demonstrate that Tec plays a role in TCR signaling leading to IL-2 gene induction. Interestingly, Tec kinases are the only known family of tyrosine kinases containing a pleckstrin homology (PH) domain. Using several PH domain mutants overexpressed in Jurkat T cells, we show that the Tec PH domain is required for Tec-mediated IL-2 gene induction and TCR-mediated Tec tyrosine phosphorylation. Furthermore, we show that Tec colocalizes with the TCR after TCR cross-linking, and that both the Tec PH and Src homology (SH) 2 domains play a role in this association. Wortmannin, a phosphatidylinositol 3-kinase inhibitor, abolishes Tec-mediated IL-2 gene induction and Tec tyrosine phosphorylation, and partially suppresses Tec colocalization with the activated TCR. Thus, our data implicate the Tec kinase PH domain and phosphatidylinositol 3-kinase in Tec signaling downstream of the TCR.

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Section: The Importance Of the Ph Domain In Tec Family Kinasessupporting

confidence: 90%

Tec Kinase Signaling in T Cells Is Regulated by Phosphatidylinositol 3-Kinase and the Tec Pleckstrin Homology Domain

Yang

Ching

Tsoukas

et al. 2001

The Journal of Immunology

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“…The structure of several PH domains has been determined (Ferguson et al, 1994(Ferguson et al, , 1995Fushman et al, 1995;Hyvonen et al, 1995;Macias et al, 1994;Timm et al, 1994;Yoon et al, 1994). These structures exhibit a common globular fold that consists of seven anti-parallel b strands and an a helix (Gibson et al, 1994;Lemmon et al, 1996).…”

Section: A Structural Model Of the Akt Ph Domainmentioning

confidence: 99%

“…Our early studies, identifying Akt as a direct target of the PI3-K, showed that an Akt immunoprecipitate from lysates of serum-starved NIH3T3 cells was activated when incubated with D3 phosphorylated phosphoinositides (D3 PPIs) . Since the activation of Akt by PDGF requires an intact Akt pleckstrin homology (PH) domain and since PH domains bind phospholipids (Harlan et al, 1994;Hyvonen et al, 1995), these ®ndings suggested that Akt activation may depend on the binding of D3 PPIs to the Akt PH domain . This was con®rmed and extended by studies that examined the role of de®ned D3 PPIs in Akt activation.…”

Section: Introductionmentioning

confidence: 99%

Akt activation by growth factors is a multiple-step process: the role of the PH domain

et al. 1998

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The protein kinase encoded by the Akt proto-oncogene is activated by phospholipid binding, membrane translocation and phosphorylation. To address the relative roles of these mechanisms of Akt activation, we have employed a combination of genetic and pharmacological approaches. Transient transfection of NIH3T3 cells with wild-type Akt, pleckstrin homology (PH) domain mutants, generated on the basis of a PH domain structural model, and phosphorylation site Akt mutants provided evidence for a model of Akt activation consisting of three sequential steps: (1) a PH domain-dependent, growth factor-independent step, marked by constitutive phosphorylation of threonine 450 (T450) and perhaps serine 124 (S124), that renders the protein responsive to subsequent activation events; (2) a growth factor-induced, PI3-K-dependent membrane-translocation step; and (3) a PI3-K-dependent step, characterized by phosphorylation at T308 and S473, that occurs in the cell membrane and is required for activation. When forced to translocate to the membrane, wild-type Akt and PH domain Akt mutants that are defective in the ®rst step become constitutively active, suggesting that the purpose of this step is to prepare the protein for membrane translocation. Both growth factor stimulation and forced membrane translocation, however, failed to activate a T308A mutant. This, combined with the ®nding that T308D/S473D double mutant is constitutively active, suggests that the purpose of the three-step process of Akt activation is the phosphorylation of the protein at T308 and S473. The proposed model provides a framework for a comprehensive understanding of the temporal and spatial requirements for Akt activation by growth factors.

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“…The interacting counterpart is the WD40 repeats of the ␤ subunit of G-protein (20). More recently, several studies showed that various PH domains bind to phosphatidylinositol 4,5-bisphosphate (PIP 2 ) and inositol 1,4,5-trisphosphate (IP 3 ) through their positively charged residues in the amino-terminal four ␤-sheets (15,21,22). PIP 2 interactions with the amino-terminal PH domain of pleckstrin (21) and the PLC-␦1 PH domain (22) (30), and Txk/Rlk (31,32).…”

mentioning

confidence: 99%

Interactions between Protein Kinase C and Pleckstrin Homology Domains

Yao

Suzuki

Ozawa

et al. 1997

Journal of Biological Chemistry

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Pleckstrin homology (PH) domains comprised of loosely conserved sequences of ϳ100 amino acid residues are a functional protein motif found in many signal-transducing and cytoskeletal proteins. We recently demonstrated that the PH domains of Tec family protein-tyrosine kinases Btk and Emt (equal to Itk and Tsk) interact with protein kinase C (PKC) and that PKC down-regulates Btk by phosphorylation. In this study we have characterized the PKC-BtkPH domain interaction in detail. Using pure PKC preparations, it was shown that the Btk PH domain interacts with PKC with high affinity (K D ‫؍‬ 39 nM). Unlike other tested phospholipids, phosphatidylinositol 4,5-bisphosphate, which binds to several PH domains, competed with PKC for binding to the PH domain apparently because their binding sites on the amino-terminal portion of the PH domains overlap. The minimal PKC-binding sequence within the Btk PH domain was found to correspond roughly to the second and third ␤-sheets of the PH domains of known tertiary structures. On the other hand, the C1 regulatory region of PKC⑀ containing the pseudosubstrate and zinc finger-like sequences was found to be sufficient for strong binding to the Btk PH domain. Phorbol 12-myristate 13-acetate (PMA), a potent activator of PKC that interacts with the C1 region of PKC, inhibited the PKC-PH domain interaction, whereas the bioinactive PMA (4-␣-PMA) was ineffective. The isoform of PKC, which has a single zinc finger-like motif instead of the two tandem zinc finger-like sequences present in conventional and novel PKC isoforms, does not bind PMA. Thus, as expected, PH domain binding with PKC was not interfered with by PMA. Further, inhibitors that are known to attack the catalytic domains of serine/threonine kinases did not affect this PKC-PH domain interaction. In contrast, the presence of physiological concentrations of Ca 2؉ induced less than a 2-fold increase in PKC-PH domain binding. These results indicate that PKC binding to PH domains involve the ␤2-␤3 region of the Btk PH domain and the C1 region of PKC, and agents that interact with either of these regions (i.e. phosphatidylinositol 4,5-bisphosphate binding to the PH domain and PMA binding to the C1 region of PKC) might act to regulate PKC-PH domain binding.

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Structure of the binding site for inositol phosphates in a PH domain.

Cited by 336 publications

References 39 publications

Tec Kinase Signaling in T Cells Is Regulated by Phosphatidylinositol 3-Kinase and the Tec Pleckstrin Homology Domain

Tec Kinase Signaling in T Cells Is Regulated by Phosphatidylinositol 3-Kinase and the Tec Pleckstrin Homology Domain

Akt activation by growth factors is a multiple-step process: the role of the PH domain

Interactions between Protein Kinase C and Pleckstrin Homology Domains

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