Lipid-transfer proteins: a puzzling family of plant proteins

Kader, Jean‐Claude

doi:10.1016/s1360-1385(97)82565-4

Cited by 228 publications

(177 citation statements)

References 32 publications

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“…Lipid transfer proteins (LTPs) are a group of extracellular proteins of many proposed functions (Kader, 1996(Kader, , 1997. In this screen, 18 sequences with distant homology to Arabidopsis LTPs were identified.…”

Section: Ltpl Proteins (18)mentioning

confidence: 99%

Prediction of Glycosylphosphatidylinositol-Anchored Proteins in Arabidopsis. A Genomic Analysis

et al. 2002

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Glycosylphosphatidylinositol (GPI) anchoring of proteins provides a potential mechanism for targeting to the plant plasma membrane and cell wall. However, relatively few such proteins have been identified. Here, we develop a procedure for database analysis to identify GPI-anchored proteins (GAP) based on their possession of common features. In a comprehensive search of the annotated Arabidopsis genome, we identified 167 novel putative GAP in addition to the 43 previously described candidates. Many of these 210 proteins show similarity to characterized cell surface proteins. The predicted GAP include homologs of ␤-1,3-glucanases (16), metallo-and aspartyl proteases (13), glycerophosphodiesterases (6), phytocyanins (25), multi-copper oxidases (2), extensins (6), plasma membrane receptors (19), and lipid-transfer-proteins (18). Classical arabinogalactan (AG) proteins (13), AG peptides (9), fasciclin-like proteins (20), COBRA and 10 homologs, and novel potential signaling peptides that we name GAPEPs (8) were also identified. A further 34 proteins of unknown function were predicted to be GPI anchored. A surprising finding was that over 40% of the proteins identified here have probable AG glycosylation modules, suggesting that AG glycosylation of cell surface proteins is widespread. This analysis shows that GPI anchoring is likely to be a major modification in plants that is used to target a specific subset of proteins to the cell surface for extracellular matrix remodeling and signaling.Conventional membrane proteins possess one or more transmembrane domains that traverse the hydrophobic lipid bilayer. A glycosylphosphatidylinositol (GPI) anchor is an alternative means of attaching a protein to the membrane (for review, see Udenfriend and Kodukula, 1995), and it is found in all eukaryotic organisms. The C terminus of a GPIanchored protein (GAP) is covalently attached via phosphoethanolamine and a conserved glycan to phosphatidylinositol or a ceramide (Kinoshita and Inoue, 2000). GAPs have many features that distinguish them from proteins with transmembrane domains. The anchor can be removed by the action of specific phospholipases (Griffith and Ryan, 1999), converting the protein into a water-soluble form. In many organisms, they are found specifically at the outer leaflet of the plasma membrane (PM). It is important that GPI anchoring can target proteins to the PM in a polarized or localized manner, for example to the apical membrane of polarized mammalian epithelial cells (Le Gall et al., 1995) or the axon of neurons (Brown et al., 2000). As part of this targeting mechanism, GAPs are thought to associate with lipid rafts (Muniz and Riezman, 2000;Ikonen, 2001), and there is evidence for rafting of GAPs in plants ( Peskan et al., 2000). Therefore, this class of proteins forms a potentially important group of molecules involved in plant cell surface generation and remodeling (Sherrier et al., 1999).GAPs have only relatively recently been discovered in plants. Arabinogalactan (AG) proteins (AGPs), cell surface proteo...

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Section: Ltpl Proteins (18)mentioning

confidence: 99%

Prediction of Glycosylphosphatidylinositol-Anchored Proteins in Arabidopsis. A Genomic Analysis

et al. 2002

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“…Although plant LTPs have been the subject of extensive studies (see Kader, 1996a,Kader, 1996b, their in vivo function has not been established and the problem of reconciling their extracellular peripheral cell location with in vitro lipid transfer activity has been widely recognised. It is possible that LTPs are dual-function proteins, with both antimicrobial and lipid transfer activity.…”

Section: Functional Significancementioning

confidence: 99%

“…The biological function of LTPs is a puzzle since although their involvement in the intracellular flux of lipids is suggested by their in vitro activity, analysis of proteins and cDNA clones in a number of species shows that they are synthesised with N-terminal signal sequences which are cleaved from the mature protein, and this indicates an extracellular location (Kader, 1996a;Kader, 1996b). Because of their extracellular location and gene expression in epidermal cells, it has been suggested that, in vivo, they may be involved in cutin and surface wax deposition rather than lipid transfer (Sterk et al, 1991;Pyee et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

Keresztessy

Hughes

1998

The Plant Journal

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SummaryThe homology modelling technique was used to predict the tertiary structures of three members of the lowtemperature-inducible barley vegetative shoot epidermal lipid-transfer protein (LTP) family, BLT4, on the basis of the X-ray crystallographically determined three-dimensional structure of a maize seedling LTP. Differences between the maize LTP and the BLT4 family include amino acid substitutions around the entrance and inside the predicted hydrophobic binding tunnels of these proteins. Because of the deletion of the loop region corresponding to Val60-Gly62 of the maize LTP from all three BLT4 LTPs, their internal hydrophobic tunnels are longer. Molecular dynamics modelling shows that BLT4.9 can accommodate hexadecanoic acid in its binding tunnel in similar conformation to the maize LTP. However, modelled cis,cis-9,12-octadecandienoic acid had a more favourable interaction with the BLT4.9 LTP than with the maize protein. Di-cis,cis-9,12-octadecandienoyl phosphatidylglycerol and di-cis,cis-9,12-octadecandienoyl phosphatidylcholine were modelled in the BLT4.9 structure with the fatty acyl group at position 1 embedded in the binding tunnel and the group at position 2 located on the solvent accessible surface of the protein. The results of the modelling suggest that the phospholipid headgroup can form hydrogen and salt bridges with polar and charged residues outside the binding tunnel and the exposed hydrocarbon chain interacts with hydrophobic amino acids on the surface. These results are consistent with the proposal that BLT4 LTPs have a lipid-transfer function associated with frost acclimation in barley.

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“…[1][2][3][4][5] Unlike their animal counterparts, plant LTPs typically have broad substrate specificity and are also named nonspecific LTPs. Their affinity for lipids is presumed to be crucial for their biological function, but in vivo substrates remain largely unknown.…”

Section: Introductionmentioning

confidence: 99%

On the role of a Lipid-Transfer Protein. Arabidopsis ltp3 mutant is compromised in germination and seedling growth.

Pagnussat

Oyarburo

Cimmino³

et al. 2015

Plant Signaling & Behavior

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Lipid-transfer proteins: a puzzling family of plant proteins

Cited by 228 publications

References 32 publications

Prediction of Glycosylphosphatidylinositol-Anchored Proteins in Arabidopsis. A Genomic Analysis

Prediction of Glycosylphosphatidylinositol-Anchored Proteins in Arabidopsis. A Genomic Analysis

Homology modelling and molecular dynamics aided analysis of ligand complexes demonstrates functional properties of lipid‐transfer proteins encoded by the barley low‐temperature‐inducible gene family, blt4

On the role of a Lipid-Transfer Protein. Arabidopsis ltp3 mutant is compromised in germination and seedling growth.

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