Disease relevance of EPB42

• Individuals whose red blood cells are deficient in P4.2 have osmotically fragile, abnormally shaped cells and moderate hemolytic anemia. cDNA clones from both the 5' and the 3' coding regions of the P4.2 gene were used to map its chromosomal location by fluorescence in situ hybridization [1].
• A novel mutation in the erythrocyte protein 4.2 gene of Japanese patients with hereditary spherocytosis (protein 4.2 Fukuoka) [2].
• The sensitivity to gentamicin (G) and to amikacin (A) of 25 strains of Escherichia coli (EC), 25 Klebsiella sp. (K), 25 Proteus and Providence sp. (PP), and 25 Ps. aeruginosa (PA) were tested in vitro by the disc method, by the inocula-replicating method, and by a tube dilution technique using 10-5 microorganisms/ml [3].
• Increased serum insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) proteolytic activity (IGFBP-3-PA) has been demonstrated in a number of clinical states of insulin resistance, including severe illness, after surgery, and in noninsulin-dependent diabetes mellitus [4].
• This study was designed to investigate the effects of 5alpha-dihydrotestosterone (DHT), epidermal growth factor (EGF), transforming growth factor beta1 (TGFbeta1), retinoic acid and basic fibroblastic growth factor (bFGF) on cell growth and PA expression and secretion in DU145 and PC3 cells, 2 human prostatic-cancer cell lines [5].

High impact information on EPB42

• Protein 4.2 (P4.2), one of the major components of the red-blood-cell membrane, is located on the interior surface, where it binds with high affinity to the cytoplasmic domain of band 3 [1].
• The gene for human erythrocyte protein 4.2 maps to chromosome 15q15 [1].
• P4.2 deficiency does not affect band 3 anion transport activity, since uptake of radiolabeled sulfate was similar for control and P4.2-deficient RBCs [6].
• It is unclear whether other cytoskeletal proteins participate in strengthening the ankyrin-band 3 linkage, but a putative role for protein 4.2 (P4.2) has been proposed based on the increased osmotic fragility and spherocytic morphology of P4.2-deficient red blood cells (RBCs) [6].
• Since band 3 oligomers selectively associate with the cytoskeleton, these results are consistent with a weakened band 3-cytoskeleton linkage in P4.2-deficient RBC membranes [6].

Chemical compound and disease context of EPB42

• Imipenem resistant PA bacteraemia were associated with higher incidence of septic shock (40% vs 19.8%, p < 0.02) and death (33.3%) than ISPA bacteraemias [7].
• Five factors were associated with a decrement in CrCl greater than the average decrease (17.6%): presence of hydronephrosis, age <50, no history of cisplatin treatment, a BED to gross adenopathy exceeding mean BED, and salvage treatment of PA node recurrence [8].

Biological context of EPB42

• Hence, the genes for B3, P4.2, and beta-spectrin (beta-SP) appear to be suitable models to study the relationship between methylation of promoter 5'-CG-3' sites and the sequential expression of genes during human erythroid development and differentiation [9].
• The octyl-beta-glucoside ghost extracts from both P4.2-deficient phenotypes were enriched in band 3 oligomeric species (tetramers, higher-order oligomers, and aggregates) compared with controls [6].
• The molecular basis of Japanese P4.2-deficiency was investigated by reverse transcription of total reticulocyte RNA, followed by polymerase chain reaction (PCR) amplification, subcloning, and sequencing [10].
• The complete cDNA sequence of a P4.2-deficient patient showed a single point mutation that changes codon 142 from GCT (alanine) to ACT (threonine) (Protein 4.2NIPPON) [10].
• The major membrane binding site for P4.2 is contained within the cytoplasmic domain of band 3 (cdb3), although the precise location of the cdb3 binding site is not known [11].

Anatomical context of EPB42

• Messenger RNA (mRNA) from ELB42 is first detected in early erythroblasts, and P4.2 is expressed in late erythroblasts [9].
• Immuno-analogues of erythrocyte protein 4.2 in thyroid gland [12].
• Phosphatidic acid phosphohydrolase (PPH) activity was determined in human polymorphonuclear leukocytes (PMNs) by measuring the hydrolysis of [32P]phosphatidic acid (PA) added to cell sonicates [13].
• In this study we have investigated the effects of calcitriol and PMA-induced differentiation on the comparative expression of PA and PAI in monoblast-like U937 cells [14].
• Enfamil (Mead Johnson, Evansville, IN) contained three times as much linoleic acid as human milk or SMA (Wyeth Laboratories, Philadelphia, PA); however, the ratios of linoleic/alpha-linolenic acid were 9.0, 18.8, and 11.7 for Enfamil, human milk, and SMA, respectively [15].

Associations of EPB42 with chemical compounds

• Molecular cloning of P4.2 cDNAs showed that P4.2 is a transglutaminaselike molecule in erythrocytes but lacks the essential cysteine for cross-linking activity [16].
• Human erythrocyte membrane protein band 4.2 (pallidin) [17].
• Control cells uniformly secreted PAI activity (70.3 +/- 24.9 PAI U/ml), while calcitriol pretreatment induced the cells to secrete PA activity (52.6 +/- 47.2 milli-Ploug unit/ml) [14].
• Eight patients receiving an oral glucose load before surgery demonstrated a significant greater relative increase in IGFBP-3-PA compared with 10 patients not receiving glucose (32.9 +/- 7.1% vs. 8.6 +/- 6.7%, respectively; P < 0.05) [4].
• Nevertheless, u-PA mRNA level in EGF-, TGFbeta1 - or DHT-treated cells was amplified only between 110 and 180% of control, suggesting that growth factors differently controlled the steps of PA expression [5].

Other interactions of EPB42

• Protein 4.1 appears next, followed by protein 4.2 (P4.2) at the very late erythroblast stage [9].
• Finally, a specific HDAC inhibitor attenuated Brg1-directed repression of P4.2 promoter activity in transfected cells [18].
• By in situ hybridization of a full-length 2.4-kilobase (kb) cDNA to human metaphase chromosomes, the gene for P4.2 was mapped to bands q15-q21 of chromosome 15, and it is not linked to the gene for coagulation factor XIIIa (plasma transglutaminase, TGase) [16].

Analytical, diagnostic and therapeutic context of EPB42

• Micro-aggregation (PA) and macro-aggregation (TA) were determined respectively by electronic particle counting and light transmission (turbidimetry) [19].
• We carried out a cross sectional and longitudinal study to assess whether bioimpedance indexes (resistance, Rz; reactance, Xc; phase angle, PA) reflect the nutritional status of hemodialysis (HD) patients, and bear a significant association with their long-term survival [20].
• STUDY OBJECTIVES: To compare adherence and clinical outcomes between flexible positive airway pressure (PAP) [C-Flex; Respironics; Murraysville, PA] and standard PAP therapy (ie, continuous positive airway pressure [CPAP]) [21].
• Among these monoclonal antibodies, only five reacted with PA in A/PR/8/34 virus-infected cells in indirect immunofluorescence assay [22].
• Twenty-two monoclonal antibodies reacting with PA protein in ELISA were divided into 10 groups on the basis of competitive binding patterns to this protein [22].

References