Evidence that the hydrophobicity of isolated, in situ, and de novo-synthesized native human placental folate receptors is a function of glycosyl-phosphatidylinositol anchoring to membranes.

Verma, Rama Shanker; Gullapalli, Sharada; Antony, Asok

doi:10.1016/s0021-9258(19)50637-8

Cited by 59 publications

(12 citation statements)

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“…binding proteins (sFBPs) isolated from leukemic spleen (Sadasivan et al, 1986(Sadasivan et al, , 1987 are in all likelihood derived from FR-/3 or FR-y since (a) FRs have been clearly shown to be the precursors of sFBPs in KB cells and placenta (Luhrs & Soliamy, 1989;Verma et al, 1992;Antony et al, 1989;Elwood et al, 1991) and (b) the soluble and membraneassociated folate binding proteins in leukemic spleen were immunologically cross-reactive (Sadasivan et al, 1986(Sadasivan et al, ,1987. Serum sFBP is elevated in cancer and several pathologic states (Rothenberg & da Costa, 1971;Corrocher et al, 1979;Rochman et al, 1985).…”

Section: Membrane-anchoring Of [3h]folic Acid Binding Proteinmentioning

confidence: 99%

“…The two known isoforms of the human cell surfaceassociated high-affinity folate receptor (FR) are homologous polypeptides of Mt ~28 000 that are N-glycosylated and attached to the membrane by a glycosylphosphatidylinositol (GPI) anchor (Ratnam et al, 1989;Sadasivan & Rothenberg, 1989;Elwood, 1989;Lacey et al, 1989; Luhrs & Sloliamy, 1989;Verma et al, 1992). Although a dual functional role has been proposed for FR, i.e., cellular transport of folate compounds/anti-folates [reviewed in Antony (1992); Jansen etal., 1990; Westerhof etal., 1991;Luhrs etal., 1992;Matsue et al, 1992] and stimulation of cell growth in primary bone marrow cultures (Antony et al, 1991), the physiological significance of FR expression in various tissues is still unclear.…”

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confidence: 99%

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Identification of a novel folate receptor, a truncated receptor, and receptor type .beta. in hematopoietic cells: cDNA cloning, expression, immunoreactivity, and tissue specificity

et al. 1994

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The expression of a membrane-associated folate receptor (FR) was elevated in spleen samples from patients with chronic (CML) and acute (AML) myelogenous leukemias compared with normal spleen. Contrary to earlier reports, antibodies to a purified FR from placenta cross-reacted quantitatively with this protein in solution radioimmunoassays. Similar to FR-alpha (KB cells) and FR-beta (placenta), the protein was released from the membrane by phosphatidylinositol-specific phospholipase C, indicating a glycosylphosphatidylinositol (GPI) membrane anchor. Screening of a cDNA library from CML spleen with a heterologous murine FR cDNA and also amplification of FR cDNAs from spleen and bone marrow in CML, AML, chronic lymphocytic leukemia (CLL), and acute lymphocytic leukemia (ALL) by polymerase chain reaction (PCR) using degenerate oligonucleotides yielded cDNA clones representing FR-beta, a novel FR (type gamma), and an aberrant transcript of FR-gamma with a 2 base pair deletion resulting in a truncated 104-residue polypeptide; FR-alpha was not detected in these tissues. The cDNA for FR-gamma predicts a 243-residue polypeptide with an amino acid sequence homology of 71% and 79% with FR-alpha and FR-beta, respectively, a 23-residue amino-terminal signal peptide, and 3 potential sites for N-linked glycosylation. Transfection of COS-1 cells with the cDNA for FR-gamma resulted in low expression of a [3H]folic acid binding protein on the cell surface that was GPI-anchored. PCR analysis of total RNA from a number of normal and malignant tissues and cell lines indicated a limited tissue specificity of FR-gamma.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Membrane-anchoring Of [3h]folic Acid Binding Proteinmentioning

confidence: 99%

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confidence: 99%

Identification of a novel folate receptor, a truncated receptor, and receptor type .beta. in hematopoietic cells: cDNA cloning, expression, immunoreactivity, and tissue specificity

et al. 1994

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“…In general, FR-a is expressed in epithelial cells and is elevated in malignancies of epithelial origin, whereas FR-/3 is elevated in malignancies of nonepithelial origin (Ross et al, 1994). The proteins are attached to the plasma membrane by GPI membrane anchors (Lacey et al, 1989;Luhrs & Slomiany, 1989;Verma et al, 1992). A third FR isoform, type y, that is expressed in hematopoietic tissues is constitutively secreted because of a divergence of its carboxyl-terminal sequence (Shen et al, 1994(Shen et al, , 1995.…”

Section: Ct Atgctgcagccatgagtatggctggggc Ggcagggatttctagatatcagggcagmentioning

confidence: 99%

Preferred Sites of Glycosylphosphatidylinositol Modification in Folate Receptors and Constraints in the Primary Structure of the Hydrophobic Portion of the Signal

Wu¹,

Ratnam²

1995

Biochemistry

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The divergent carboxyl-terminal signal peptides for glycosylphosphatidylinositol (GPI) membrane anchor attachment in folate receptor (FR) types alpha and beta were characterized. All of the candidate amino acid residues for GPI modification were identified and tested by substituting individually and in combination with amino acids that cannot be modified by GPI. Thus the GPI modification in FR-alpha was decreased to 22% by mutation of Ser234 to Thr but unaltered by changing the other candidate, Gly235, to Met. However, the double mutant FR-alpha Ser234-Thr,Gly235-Met showed half of the GPI modification seen in FR-alpha Ser234-Thr. This result suggests that Ser234 is the preferred GPI modification site, while Gly235 is a minor, alternate GPI modification site. Similarly, in FR-beta, mutation of Asn230 to Gln decreased GPI modification to 32%, while mutation of the other candidate site, Gly237, to Met had no effect. However, mutation at both sites further reduced the GPI modification by a half. A five amino acid carboxyl-terminal deletion (FR-beta delta 5) caused no decrease in the extent of GPI modification. However, the same deletion in FR beta Asn230-Gln decreased the residual GPI modification by 66%. These results suggest that Asn230 is the preferred GPI modification site in FR-beta, while Gly235 offers a minor alternate modification site; consistent with this conclusion is the fact that modification at the downstream site is hindered by its proximity to the carboxyl terminus in FR-beta delta 5. Further, the suggestion that the hydrophobic portion of the GPI signal is a random sequence of neutral amino acids with overall moderate hydrophobicity was tested.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Although low, these labelling efficiencies are sufficient for positive identification of protein segments and as a result 69 has been used extensively for this purpose. 33,230 Transmembrane peptide components have been identified (using 69) from a variety of enzymes, including: ATPase, 231-235 ACE, 236,237 c-glutamyl transcriptidase, 238 cytosolic phospholipase A2, 239 CTP: phosphocholine cytidylyltransferase, 240 acetylcholinesterase, 241 and proteins, including: calmodulin, 197 annexin proteins, 242,243 heterotrimeric G proteins, 244 apolipoprotein, 245 junctional foot protein, 246 plasma membrane Ca 2+ pump, 247 amoyloid precursor protein, 248 laminin binding protein, 249 myelin basic protein, [250][251][252] bacteriorhodopsin, 253 heparan sulfate proteoglycans, 254,255 clathrin, 256 synapsin I, 257 synaptotagmin, 239 glycoprotein anti-cardiolipin antibodies, 258 placental folate receptors 259 and AChR. 203,[260][261][262] The photolabel 69 has also been used to identify polymorphic and major outer membrane proteins in…”

Section: Application Of Hydrophilic Diazirines In Membrane Topographymentioning

confidence: 99%

Development and application of diazirines in biological and synthetic macromolecular systems

2005

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Many different reagents and methodologies have been utilised for the modification of synthetic and biological macromolecular systems. In addition, an area of intense research at present is the construction of hybrid biosynthetic polymers, comprised of biologically active species immobilised or complexed with synthetic polymers. One of the most useful and widely applicable techniques available for functionalisation of macromolecular systems involves indiscriminate carbene insertion processes. The highly reactive and non-specific nature of carbenes has enabled a multitude of macromolecular structures to be functionalised without the need for specialised reagents or additives. The use of diazirines as stable carbene precursors has increased dramatically over the past twenty years and these reagents are fast becoming the most popular photophors for photoaffinity labelling and biological applications in which covalent modification of macromolecular structures is the basis to understanding structure-activity relationships. This review reports the synthesis and application of a diverse range of diazirines in macromolecular systems.

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Evidence that the hydrophobicity of isolated, in situ, and de novo-synthesized native human placental folate receptors is a function of glycosyl-phosphatidylinositol anchoring to membranes.

Cited by 59 publications

References 54 publications

Identification of a novel folate receptor, a truncated receptor, and receptor type .beta. in hematopoietic cells: cDNA cloning, expression, immunoreactivity, and tissue specificity

Identification of a novel folate receptor, a truncated receptor, and receptor type .beta. in hematopoietic cells: cDNA cloning, expression, immunoreactivity, and tissue specificity

Preferred Sites of Glycosylphosphatidylinositol Modification in Folate Receptors and Constraints in the Primary Structure of the Hydrophobic Portion of the Signal

Development and application of diazirines in biological and synthetic macromolecular systems

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