scholarly journals Phosphatidylserine binding is important for plasma membrane targeting of 3′‐phosphoinositide‐dependent kinase‐1 pleckstrin homology domain

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Nathan Thomas Lucas ◽  
Hee‐Yong Kim ◽  
Wonhwa Cho
Keyword(s):  
Plasma Membrane ◽  
Pleckstrin Homology Domain ◽  
Membrane Targeting ◽  
Pleckstrin Homology ◽  
Phosphoinositide Dependent Kinase

scholarly journals Role for the Pleckstrin Homology Domain-Containing Protein CKIP-1 in Phosphatidylinositol 3-Kinase-Regulated Muscle Differentiation

2004 ◽  
Vol 24 (3) ◽  
pp. 1245-1255 ◽  
Author(s):  
Alexias Safi ◽  
Marie Vandromme ◽  
Sabine Caussanel ◽  
Laure Valdacci ◽  
Dominique Baas ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Active Form ◽  
Muscle Differentiation ◽  
C2c12 Cells ◽  
Pleckstrin Homology Domain ◽  
Dependent Manner ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

ABSTRACT In this work, we report the implication of the pleckstrin homology (PH) domain-containing protein CKIP-1 in phosphatidylinositol 3-kinase (PI3-K)-regulated muscle differentiation. CKIP-1 is upregulated during muscle differentiation in C2C12 cells. We show that CKIP-1 binds to phosphatidylinositol 3-phosphate through its PH domain and localizes to the plasma membrane in a PI3-K-dependent manner. Activation of PI3-K by insulin or expression of an active form of PI3-K p110 induces a rapid translocation of CKIP-1 to the plasma membrane. Conversely, expression of the 3-phosphoinositide phosphatase myotubularin or PI3-K inhibition by LY294002, wortmannin, or mutant p85 abolishes CKIP-1 binding to the membrane. Upon induction of differentiation in low-serum medium, CKIP-1 overexpression in C2C12 myoblasts first promotes proliferation and then stimulates the expression of myogenin and cell fusion in a manner reminiscent of the dual positive effect of insulin-like growth factors on muscle cells. Interference with the PI3-K pathway impedes the effect of CKIP-1 on C2C12 cell differentiation. Finally, silencing of CKIP-1 by RNA interference abolishes proliferation and delays myogenin expression. Altogether, these data strongly implicate CKIP-1 as a new component of PI3-K signaling in muscle differentiation.

scholarly journals Membrane Targeting of Grb2-associated Binder-1 (Gab1) Scaffolding Protein through Src Myristoylation Sequence Substitutes for Gab1 Pleckstrin Homology Domain and Switches an Epidermal Growth Factor Response to an Invasive Morphogenic Program

2003 ◽  
Vol 14 (4) ◽  
pp. 1691-1708 ◽  
Author(s):  
Christiane R. Maroun ◽  
Monica A. Naujokas ◽  
Morag Park
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epithelial Cells ◽  
Subcellular Localization ◽  
Epithelial Morphogenesis ◽  
Pleckstrin Homology Domain ◽  
Membrane Targeting ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Epidermal Growth

The hepatocyte growth factor receptor tyrosine kinase Met promotes cell dissociation and the inherent morphogenic program of epithelial cells. In a search for substrates downstream from Met, we have previously identified the Grb2-associated binder-1 (Gab1) as critical for the morphogenic program. Gab1 is a scaffold protein that acts to diversify the signal downstream from the Met receptor through its ability to couple with multiple signal transduction pathways. Gab1 contains a pleckstrin homology (PH) domain with specificity for phosphatidylinositol 3,4,5-trisphosphate. The phospholipid binding capacity of the Gab1 PH domain is required for the localization of Gab1 at sites of cell-cell contact in colonies of epithelial cells and for epithelial morphogenesis, suggesting that PH domain-dependent subcellular localization of Gab1 is a prerequisite for function. We have investigated the requirement for membrane localization of Gab1 for biological activity. We show that substitution of the Gab1 PH domain with the myristoylation signal from the c-Src protein is sufficient to replace the Gab1 PH domain for epithelial morphogenesis. The membrane targeting of Gab1 enhances Rac activity in the absence of stimulation and switches a nonmorphogenic noninvasive response to epidermal growth factor to a morphogenic invasive program. These results suggest that the subcellular localization of Gab1 is a critical determinant for epithelial morphogenesis and invasiveness.

scholarly journals Role of Pleckstrin Homology Domain in Regulating Membrane Targeting and Metabolic Function of Insulin Receptor Substrate 3

2003 ◽  
Vol 17 (8) ◽  
pp. 1568-1579 ◽  
Author(s):  
Tania Maffucci ◽  
Giorgia Razzini ◽  
Alessandra Ingrosso ◽  
Hui Chen ◽  
Stefano Iacobelli ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Pleckstrin Homology Domain ◽  
Membrane Targeting ◽  
Insulin Receptor Substrate ◽  
Metabolic Function ◽  
Pleckstrin Homology

Subcellular localization of phosphatidylinositol 4,5-bisphosphate using the pleckstrin homology domain of phospholipase C δ1

2002 ◽  
Vol 363 (3) ◽  
pp. 657-666 ◽  
Author(s):  
Stephen A. WATT ◽  
Gursant KULAR ◽  
Ian N. FLEMING ◽  
C. Peter DOWNES ◽  
John M. LUCOCQ
Keyword(s):  
Plasma Membrane ◽  
High Resolution ◽  
Protein Complexes ◽  
Pleckstrin Homology Domain ◽  
Ph Domain ◽  
Pleckstrin Homology ◽  
Functional Protein ◽  
A431 Cells ◽  
Wide Range ◽  
Vesicular Membrane

Ptd(4,5)P2 is thought to promote and organize a wide range of cellular functions, including vesicular membrane traffic and cytoskeletal dynamics, by recruiting functional protein complexes to restricted locations in cellular membranes. However, little is known about the distribution of PtdIns(4,5)P2 in the cell at high resolution. We have used the pleckstrin homology (PH) domain of phospholipase δ1 (PLCδ1), narrowly specific for PtdIns(4,5)P2, to map the distribution of the lipid in astrocytoma and A431 cells. We applied the glutathione S-transferase-tagged PLCδ1 PH domain (PLCδ1PH—GST) in an on-section labelling approach which avoids transfection procedures. Here we demonstrate PtdIns(4,5)P2 labelling in the plasma membrane, and also in intracellular membranes, including Golgi (mainly stack), endosomes and endoplasmic reticulum, as well as in electron-dense structures within the nucleus. At the plasma membrane, labelling was more concentrated over lamellipodia, but not in caveolae, which contained less than 10% of the total cell-surface labelling. A dramatic decrease in signal over labelled compartments was observed on preincubation with the cognate headgroup [Ins(1,4,5)P3], and plasma-membrane labelling was substantially decreased after stimulation with thrombin-receptor-activating peptide (SFLLRN in the one-letter amino acid code), a treatment which markedly diminishes PtdIns(4,5)P2 levels. Thus we have developed a highly selective method for mapping the PtdIns(4,5)P2 distribution within cells at high resolution, and our data provide direct evidence for this lipid at key functional locations.

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