Pleckstrin homology domains: not just for phosphoinositides

2004 ◽  
Vol 32 (5) ◽  
pp. 707-711 ◽  
Author(s):  
M.A. Lemmon

PH domains (pleckstrin homology domains) are the 11th most common domain in the human genome and are best known for their ability to target cellular membranes by binding specifically to phosphoinositides. Recent studies in yeast have shown that, in fact, this is a property of only a small fraction of the known PH domains. Most PH domains are not capable of independent membrane targeting, and those capable of doing so (approx. 33%) appear, most often, to require both phosphoinositide and non-phosphoinositide determinants for their subcellular localization. Several recent studies have suggested that small GTPases such as ARF family proteins play a role in defining PH domain localization. Some others have described a signalling role for PH domains in regulating small GTPases, although phosphoinositides may also play a role. These findings herald a change in our perspective of PH domain function, which will be significantly more diverse than previously supposed.

2007 ◽  
Vol 74 ◽  
pp. 81-93 ◽  
Author(s):  
Mark A. Lemmon

PH (pleckstrin homology) domains represent the 11th most common domain in the human proteome. They are best known for their ability to bind phosphoinositides with high affinity and specificity, although it is now clear that less than 10% of all PH domains share this property. Cases in which PH domains bind specific phosphoinositides with high affinity are restricted to those phosphoinositides that have a pair of adjacent phosphates in their inositol headgroup. Those that do not [PtdIns3P, PtdIns5P and PtdIns(3,5)P2] are instead recognized by distinct classes of domains including FYVE domains, PX (phox homology) domains, PHD (plant homeodomain) fingers and the recently identified PROPPINs (b-propellers that bind polyphosphoinositides). Of the 90% of PH domains that do not bind strongly and specifically to phosphoinositides, few are well understood. One group of PH domains appears to bind both phosphoinositides (with little specificity) and Arf (ADP-ribosylation factor) family small G-proteins, and are targeted to the Golgi apparatus where both phosphoinositides and the relevant Arfs are both present. Here, the PH domains may function as coincidence detectors. A central challenge in understanding the majority of PH domains is to establish whether the very low affinity phosphoinositide binding reported in many cases has any functional relevance. For PH domains from dynamin and from Dbl family proteins, this weak binding does appear to be functionally important, although its precise mechanistic role is unclear. In many other cases, it is quite likely that alternative binding partners are more relevant, and that the observed PH domain homology represents conservation of structural fold rather than function.


2003 ◽  
Vol 14 (4) ◽  
pp. 1691-1708 ◽  
Author(s):  
Christiane R. Maroun ◽  
Monica A. Naujokas ◽  
Morag Park

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.


2000 ◽  
Vol 350 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Mark A. LEMMON ◽  
Kathryn M. FERGUSON

Pleckstrin homology (PH) domains are small protein modules of around 120 amino acids found in many proteins involved in cell signalling, cytoskeletal rearrangement and other processes. Although several different protein ligands have been proposed for PH domains, their only clearly demonstrated physiological function to date is to bind membrane phosphoinositides. The PH domain from phospholipase C-δ1 binds specifically to PtdIns(4,5)P2 and its headgroup, and has become a valuable tool for studying cellular PtdIns(4,5)P2 functions. More recent developments have demonstrated that a subset of PH domains recognizes the products of agonist-stimulated phosphoinositide 3-kinases. Fusion of these PH domains to green fluorescent protein has allowed dramatic demonstrations of their independent ability to drive signal-dependent recruitment of their host proteins to the plasma membrane. We discuss the structural basis for this 3-phosphoinoistide recognition and the role that it plays in cellular signalling. PH domains that bind specifically to phosphoinositides comprise only a minority (perhaps 15%) of those known, raising questions as to the physiological role of the remaining 85% of PH domains. Most (if not all) PH domains bind weakly and non-specifically to phosphoinositides. Studies of dynamin-1 have indicated that oligomerization of its PH domain may be important in driving membrane association. We discuss the possibility that membrane targeting by PH domains with low affinity for phosphoinositides could be driven by alteration of their oligomeric state and thus the avidity of their membrane binding.


2000 ◽  
Vol 350 (1) ◽  
pp. 1 ◽  
Author(s):  
Mark A. LEMMON ◽  
Kathryn M. FERGUSON

2000 ◽  
Vol 14 (6) ◽  
pp. 823-836 ◽  
Author(s):  
Giorgia Razzini ◽  
Alessandra Ingrosso ◽  
Anna Brancaccio ◽  
Salvatore Sciacchitano ◽  
Diana L. Esposito ◽  
...  

1998 ◽  
Vol 143 (2) ◽  
pp. 501-510 ◽  
Author(s):  
Péter Várnai ◽  
Tamás Balla

Phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P2) pools that bind pleckstrin homology (PH) domains were visualized by cellular expression of a phospholipase C (PLC)δ PH domain–green fluorescent protein fusion construct and analysis of confocal images in living cells. Plasma membrane localization of the fluorescent probe required the presence of three basic residues within the PLCδ PH domain known to form critical contacts with PtdIns(4,5)P2. Activation of endogenous PLCs by ionophores or by receptor stimulation produced rapid redistribution of the fluorescent signal from the membrane to cytosol, which was reversed after Ca2+ chelation. In both ionomycin- and agonist-stimulated cells, fluorescent probe distribution closely correlated with changes in absolute mass of PtdIns(4,5)P2. Inhibition of PtdIns(4,5)P2 synthesis by quercetin or phenylarsine oxide prevented the relocalization of the fluorescent probe to the membranes after Ca2+ chelation in ionomycin-treated cells or during agonist stimulation. In contrast, the synthesis of the PtdIns(4,5)P2 imaged by the PH domain was not sensitive to concentrations of wortmannin that had been found inhibitory of the synthesis of myo-[3H]inositol– labeled PtdIns(4,5)P2. Identification and dynamic imaging of phosphoinositides that interact with PH domains will further our understanding of the regulation of such proteins by inositol phospholipids.


2004 ◽  
Vol 13 (5) ◽  
pp. 677-688 ◽  
Author(s):  
Jong W. Yu ◽  
Jeannine M. Mendrola ◽  
Anjon Audhya ◽  
Shaneen Singh ◽  
David Keleti ◽  
...  

2021 ◽  
Author(s):  
Kyle I.P. Le Huray ◽  
He Wang ◽  
Frank Sobott ◽  
Antreas C Kalli

Pleckstrin homology (PH) domains can recruit proteins to membranes by recognition of phosphatidylinositol phosphates (PIPs). Here we report the systematic simulation of the interactions of 100 mammalian PH domains with PIP containing model membranes. Comparison with crystal structures of PH domains bound to PIP analogues demonstrates that our method correctly identifies interactions at known canonical and non-canonical sites, while revealing additional functionally important sites for interaction not observed in the crystal structure, such as for P-Rex1 and Akt1. At the family level, we find that the β1 and β2 strands and their connecting loop constitute the primary PIP interaction site for the majority of PH domains, but we highlight interesting exceptional cases. Simultaneous interaction with multiple PIPs and clustering of PIPs induced by PH domain binding are also observed. Our findings support a general paradigm for PH domain membrane association involving multivalent interactions with anionic lipids.


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