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Query: UNIPROT:P06889 (Mol)
630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We used complementary biochemical and immunological techniques to establish that an endothelial cell transmembrane glycoprotein, GP116, is a CD44-like molecule and binds directly both to extracellular matrix components (e.g., hyaluronic acid) and to ankyrin. The specific characteristics of GP116 are as follows: (i) GP116 can be surface labeled with Na 125I and contains a wheat germ agglutinin-binding site(s), indicating that it has an extracellular domain; (ii) GP116 displays immunological cross-reactivity with a panel of CD44 antibodies, shares some peptide similarity with CD44, and has a similar 52-kDa precursor molecule, indicating that it is a CD44-like molecule; (iii) GP116 displays specific hyaluronic acid-binding properties, indicating that it is a hyaluronic acid receptor; (iv) GP116 can be phosphorylated by endogenous protein kinase C activated by 12-O-tetradecanoylphorbol-13-acetate and by exogenously added protein kinase C; and (v) GP116 and a 20-kDa tryptic polypeptide fragment of GP116 from the intracellular domain are capable of binding the membrane-cytoskeleton linker molecule, ankyrin. Furthermore, phosphorylation of GP116 by protein kinase C significantly enhances GP116 binding to ankyrin. Together, these findings strongly suggest that phosphorylation of the transmembrane glycoprotein GP116 (a CD44-like molecule) by protein kinase C is required for effective GP116-ankyrin interaction during endothelial cell adhesion events.
Mol Cell Biol 1992 Oct
PMID:A CD44-like endothelial cell transmembrane glycoprotein (GP116) interacts with extracellular matrix and ankyrin. 140 35

The glp-1 gene encodes a membrane protein required for inductive cell interactions during development of the nematode Caenorhabditis elegans. Here we report the molecular characterization of 15 loss-of-function (lf) mutations of glp-1. Two nonsense mutations appear to eliminate glp-1 activity; both truncate the glp-1 protein in its extracellular domain and have a strong loss-of-function phenotype. Twelve missense mutations and one in-frame deletion map to sites within the repeated motifs of the glp-1 protein (10 epidermal growth factor [EGF]-like and 3 LNG repeats extracellularly and 6 cdc10/SWI6, or ankyrin, repeats intracellularly). We find that all three types of repeated motifs are critical to glp-1 function, and two individual EGF-like repeats may have distinct functions. Intriguingly, all four missense mutations in one phenotypic class map to the N-terminal EGF-like repeats and all six missense mutations in a second phenotypic class reside in the intracellular cdc10/SWI6 repeats. These two clusters of mutations may identify functional domains within the glp-1 protein.
Mol Biol Cell 1992 Nov
PMID:Molecular basis of loss-of-function mutations in the glp-1 gene of Caenorhabditis elegans. 145 27

A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.
Mol Cell Biol 1992 Feb
PMID:A novel mitogen-inducible gene product related to p50/p105-NF-kappa B participates in transactivation through a kappa B site. 153 Oct 86

Hereditary ovalocytes from a Mauritian subject are extremely rigid, with a shear elastic modulus about three times that of normal cells, and have increased resistance to invasion by the malaria parasite Plasmodium falciparum in vitro. The genetic anomaly resides in band 3; the protein gives rise to chymotryptic fragments with reduced mobility in SDS/polyacrylamide gel electrophoresis, but this is a result of anomalous binding of SDS and not a higher molecular weight. Analysis of the band 3 gene reveals (1) a point mutation (Lys56----Glu), which also occurs in a common asymptomatic band 3 (Memphis) variant and governs the electrophoretic properties, and (2) a deletion of nine amino acid residues, including a proline residue, encompassing the interface between the membrane-associated and the N-terminal cytoplasmic domains. The interaction of the mutant band 3 with ankyrin appears unperturbed. The fraction of band 3 capable of undergoing translation diffusion in the membrane is greatly reduced in the ovalocytes. Cells containing the asymptomatic band 3 variant were normal with respect to all the properties that we have studied. Possible mechanisms by which a structural change in band 3 at the membrane interface could regulate rigidity are examined.
J Mol Biol 1992 Feb 20
PMID:Basis of unique red cell membrane properties in hereditary ovalocytosis. 153 5

In Discoglossus pictus eggs, only the dimple contains ionic channels active at fertilization; in particular, chloride channels are found in the central portion of the dimple, which is also the site of sperm penetration. Moreover the dimple hosts an imposing cytoskeleton, consisting of a cortical network and bundles of microfilaments extending from the microvilli. Since spectrin cross links actin and is connected through ankyrin to anion transporters in the plasma membrane of erythrocytes as well as to anion channels in other cells, we studied, in D. pictus egg, the relationship between the localization of spectrin and the high polarization of ionic channels and cytoskeletal organization. By means of immunocytochemistry, we localized spectrin exclusively in the egg dimple. In an attempt to trace back the source of spectrin localization, we immunostained sections of D. pictus ovary and localized spectrin in the nuclei of previtellogenic oocytes, where actin is also present. Antispectrin staining remained until germinal vesicle breakdown. By contrast, a cortical localization was found only when the oocytes divided into two hemispheres and into the germinative area (GA), which, after germinal vesicle breakdown, gives rise to the dimple. At this stage the antispectrin signal was particularly strong in the GA. Using Rho-pialloidin, we also established that spectrin is generally present where F-actin is found. However, spectrin and F-actin do not have the same pattern of fluorescence. In conclusion, our data suggest that spectrin may play a role in oocyte and egg polarity. In eggs, it could be instrumental in anchoring to the cytoskeleton membrane proteins such as receptors and ionic channels, including chloride-permeable channels.
Mol Reprod Dev 1990 Jun
PMID:Antispectrin antibodies stain the oocyte nucleus and the site of fertilization channels in the egg of Discoglossus pictus (Anura). 169 11

Phosphorylation changes in the erythrocyte membrane and cytoskeletal proteins as a consequence of infection by the malarial parasite Plasmodium falciparum were examined. Spectrin, band 3, band 4.1, ankyrin and glycophorin are phosphorylated in normal erythrocytes. As a consequence of invasion by the merozoite, the extracellular stage of the parasite, into 32P-prelabeled normal erythrocytes, all the major 32P-labeled erythrocyte proteins are dephosphorylated. As the parasite develops intracellularly from the immature ring stage to the mature schizont stage, selective phosphorylation of certain host proteins, spectrin, ankyrin and band 3 is observed. Band 4.1 does not appear to incorporate [32P]phosphate at any stage of parasite development. These observed phosphorylation changes may be important in the regulation of the cytoskeletal organization in P. falciparum-infected cells.
Mol Biochem Parasitol 1989 May 15
PMID:Phosphorylation of erythrocyte membrane and cytoskeleton proteins in cells infected with Plasmodium falciparum. 252 29

Human erythrocytes were fused by Trypanosoma cruzi from 7 and 14 day old culture (stationary and declination phases, respectively) while only lysis was induced by 4 day old culture parasite (exponential phase). Lysis and erythrocyte fusion were studied by phase contrast microscopy, measuring of hemolysis and gel electrophoresis. The fusogenicity is Ca2+-dependent while lysis is delayed in the absence of exogenous Ca2+. The proteolysis of erythrocyte protein bands 1, 2, 2.1, 2.3 and 3 are common features of both fusion and lysis processes. Nevertheless the breakdown rate of ankyrin (band 2.1) and band 3 are different in fused or in lysed cells. The lysis process is associated with a faster degradation of band 2.1 and increase of band 2.3 than in the case of the fusion process. By contrast, degradation of band 3 occurs faster in the fusion than in the lytic event. Treatment of fusogenic parasites but not erythrocytes with TPCK, soybean trypsin inhibitor or FCS inhibited to some extent the fusion process and the decrease of bands 1, 2, 2.1, 2.3 and 3. The results suggest that proteases from fusogenic parasites may be directly or indirectly involved in the proteolysis of band 2.1 in a way related to induction of fusion.
Mol Cell Biochem 1989 Apr 11
PMID:Trypanosoma cruzi: involvement of proteolytic activity during cell fusion induced by epimastigote form. 267 65

Isolation and characterization of the chicken erythroid anion transporter (band 3) cDNA clone, pCHB3-1, revealed that the chicken erythroid band 3 polypeptide is 844 amino acids in length with a predicted mass of 109,000 daltons. This polypeptide is composed of a hydrophilic N-terminal cytoplasmic domain and a hydrophobic C-terminal transmembrane domain. The approximately 90 N-terminal amino acids of the human and murine erythroid band 3 polypeptides are absent in the predicted sequence of the chicken erythroid band 3 polypeptide. The absence of this very acidic N-terminal region is consistent with the lack of binding of glyceraldehyde-3-phosphate dehydrogenase to chicken erythroid band 3, as well as the relatively basic isoelectric point observed for this molecule. The remainder of the cytoplasmic domain shows little similarity to the cytoplasmic domain of the murine and human erythroid band 3, with the exception of the putative ankyrin-binding site, which is highly conserved. In contrast, the transmembrane domain of the chicken band 3 polypeptide is very similar to that of the murine erythroid and human nonerythroid band 3 polypeptides. The transmembrane domain contains 10 hydrophobic regions that could potentially traverse the membrane 12 to 14 times. In addition, a variant of chicken erythroid band 3, pCHB3-2, was cloned in which one of the hydrophobic regions of pCHB3-1 is lacking. The transcript complementary to pCHB3-2 accumulated in chicken erythroid cells in a similar manner as the transcript complementary to pCHB3-1 during embryonic development. This is the first example of a transporter protein or ion channel with alternative primary structures in its membrane-spanning segments.
Mol Cell Biol 1988 Mar
PMID:Alternative primary structures in the transmembrane domain of the chicken erythroid anion transporter. 283 70

The membrane skeletal protein ankyrin was shown to be continuously acylated and deacylated with long-chain fatty acids in mature erythrocytes. At least a fraction of the lipid bound to ankyrin turned over rapidly (half-life, approximately 50 min) compared with the polypeptide backbone, which was stable throughout the erythrocyte life. This indicates a regulatory significance of the fatty acid modification for the function of ankyrin.
Mol Cell Biol 1987 Aug
PMID:Ankyrin-bound fatty acid turns over rapidly at the erythrocyte plasma membrane. 295 56

The presence and the localization of actin, spectrin and ankyrin are studied by immunofluorescence and immunoblotting in Leishmania mexicana promastigotes growing in vitro. These proteins, amphitropic in nature, coexist both in soluble and insoluble forms. Our results demonstrate that the Triton insoluble form of these proteins constitutes beside tubulin the cytoskeletal scaffold of promastigotes in close association with the plasma membrane, the axoneme and the basal body of the parasite.
Mol Biol Rep
PMID:Plasma membrane and cytoskeletal constituents in Leishmania mexicana. 297 92


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