Emerging functional roles for the glycosyl-phosphatidylinositol membrane protein anchor

Lisanti, Michael P.; Rodríguez-Boulan, Enrique; Saltiel, Alan R.

doi:10.1007/bf01871561

Cited by 104 publications

(37 citation statements)

References 140 publications

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“…Some GPI-anchored proteins become localized within the lumen of intracellular vesicles until they are secreted in a regulated manner (Lisanti et al, 1990). Additionally, the GPI anchor can act as an intracellular sorting signal, directing the attached protein to polar locations (Hooper, 1997;Schindelman et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

The ArabidopsisSKU5Gene Encodes an Extracellular Glycosyl Phosphatidylinositol–Anchored Glycoprotein Involved in Directional Root Growth[W]

et al. 2002

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To investigate how roots respond to directional cues, we characterized a T-DNA-tagged Arabidopsis mutant named sku5 in which the roots skewed and looped away from the normal downward direction of growth on inclined agar surfaces. sku5 roots and etiolated hypocotyls were slightly shorter than normal and exhibited a counterclockwise (lefthanded) axial rotation bias. The surface-dependent skewing phenotype disappeared when the roots penetrated the agar surface, but the axial rotation defect persisted, revealing that these two directional growth processes are separable. The SKU5 gene belongs to a 19-member gene family designated SKS ( SKU5 Similar) that is related structurally to the multiple-copper oxidases ascorbate oxidase and laccase. However, the SKS proteins lack several of the conserved copper binding motifs characteristic of copper oxidases, and no enzymatic function could be assigned to the SKU5 protein. Analysis of plants expressing SKU5 reporter constructs and protein gel blot analysis showed that SKU5 was expressed most strongly in expanding tissues. SKU5 was glycosylated and modified by glycosyl phosphatidylinositol and localized to both the plasma membrane and the cell wall. Our observations suggest that SKU5 affects two directional growth processes, possibly by participating in cell wall expansion.

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Section: Discussionmentioning

confidence: 99%

The ArabidopsisSKU5Gene Encodes an Extracellular Glycosyl Phosphatidylinositol–Anchored Glycoprotein Involved in Directional Root Growth[W]

et al. 2002

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“…GPI-anchored proteins may be transported selectively via ceramide-rich microdomains. Membrane protein Tat2p may also be transported from the ER to the Golgi via ceramide-rich microdomains containing GPI-anchored protein (3). GPI-anchored proteins may stabilize Tat2p-associated ceramide-rich microdomains or recruit Tat2p to the microdomains.…”

Section: Gpi-anchored Proteins Are Required For the Recruitment To Thmentioning

confidence: 99%

Glycosylphosphatidylinositol-anchored Proteins Are Required for the Transport of Detergent-resistant Microdomain-associated Membrane Proteins Tat2p and Fur4p

Okamoto

Yoko-o

Umemura

et al. 2006

Journal of Biological Chemistry

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In eukaryotic cells many cell surface proteins are attached to the membrane via the glycosylphosphatidylinositol (GPI) moiety. In yeast, GPI also plays important roles in the production of mannoprotein in the cell wall. We previously isolated gwt1 mutants and found that GWT1 is required for inositol acylation in the GPI biosynthetic pathway. In this study we isolated a new gwt1 mutant allele, gwt1-10, that shows not only high temperature sensitivity but also low temperature sensitivity. The gwt1-10 cells show impaired acyltransferase activity and attachment of GPI to proteins even at the permissive temperature. We identified TAT2, which encodes a high affinity tryptophan permease, as a multicopy suppressor of cold sensitivity in gwt1-10 cells. The gwt1-10 cells were also defective in the import of tryptophan, and a lack of tryptophan caused low temperature sensitivity. Microscopic observation revealed that Tat2p is not transported to the plasma membrane but is retained in the endoplasmic reticulum in gwt1-10 cells grown under tryptophan-poor conditions. We found that Tat2p was not associated with detergent-resistant membranes (DRMs), which are required for the recruitment of Tat2p to the plasma membrane. A similar result was obtained for Fur4p, a uracil permease localized in the DRMs of the plasma membrane. These results indicate that GPI-anchored proteins are required for the recruitment of membrane proteins Tat2p and Fur4p to the plasma membrane via DRMs, suggesting that some membrane proteins are redistributed in the cell in response to environmental and nutritional conditions due to an association with DRMs that is dependent on GPI-anchored proteins.

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“…We propose that these residues facilitate the interaction of CA IV with the negatively charged phosphate groups of the phospholipid membrane. Given the lateral mobility of the protein conferred by the GPI anchor (15,16), a complementary electrostatic interaction with the protein surface would help stabilize the orientation of the protein on the membrane surface. A model of CA IV associated with the membrane is presented in Fig.…”

Section: A Fierke Personal Communication)mentioning

confidence: 99%

“…IV isolated and purified from human kidney is a nonglycosylated 35-kDa protein that is posttranslationally cleaved and modified at the C terminus with a glycosylphosphatidylinositol (GPI) tail (13,14), a common membrane-anchoring motif (15,16). The CA IV isozyme contains two disulfide linkages which contribute to its remarkable stability upon solubilization in 5% sodium dodecyl sulfate (SDS) (12,17).…”

mentioning

confidence: 99%

Crystal structure of the secretory form of membrane-associated human carbonic anhydrase IV at 2.8-Å resolution

Stams

Nair

Okuyama

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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118

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It has recently been demonstrated that the C-terminal deletion mutant of recombinant human carbonic anhydrase IV (G267X CA IV) converts the normally glycosylphosphatidylinositol-anchored enzyme into a soluble secretory form which has the same catalytic properties as the membrane-associated enzyme purified from human tissues. We have determined the three-dimensional structure of the secretory form of human CA IV by x-ray crystallographic methods to a resolution of 2.8 Å. Although the zinc binding site and the hydrophobic substrate binding pocket of CA IV are generally similar to those of other mammalian isozymes, unique structural differences are found elsewhere in the active site. Two disufide linkages, Cys-6-Cys-11G and Cys-23-Cys-203, stabilize the conformation of the N-terminal domain. The latter disulfide additionally stabilizes an active site loop containing a cis-peptide linkage between Pro-201 and Thr-202 (this loop contains catalytic residue Thr-199). On the opposite side of the active site, the Val-131-Asp-136 segment adopts an extended loop conformation instead of an ␣-helix conformation as found in other isozymes. Finally, the C terminus is surrounded by a substantial electropositive surface potential, which is likely to stabilize the interaction of CA IV with the negatively charged phospholipid headgroups of the membrane. These structural features are unique to CA IV and provide a framework for the design of sulfonamide inhibitors selective for this particular isozyme.

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Emerging functional roles for the glycosyl-phosphatidylinositol membrane protein anchor

Cited by 104 publications

References 140 publications

The ArabidopsisSKU5Gene Encodes an Extracellular Glycosyl Phosphatidylinositol–Anchored Glycoprotein Involved in Directional Root Growth[W]

The ArabidopsisSKU5Gene Encodes an Extracellular Glycosyl Phosphatidylinositol–Anchored Glycoprotein Involved in Directional Root Growth[W]

Glycosylphosphatidylinositol-anchored Proteins Are Required for the Transport of Detergent-resistant Microdomain-associated Membrane Proteins Tat2p and Fur4p

Crystal structure of the secretory form of membrane-associated human carbonic anhydrase IV at 2.8-Å resolution

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