Disease relevance of PKLR

• Pyruvate kinase (PK) deficiency due to mutations of the PKLR gene is a common cause of hereditary nonspherocytic hemolytic anemia [1].
• Linkage disequilibrium of common Gaucher disease mutations with a polymorphic site in the pyruvate kinase (PKLR) gene [2].
• The expression of mutant RPK mRNA in the RBCs was almost 6 times higher than that detected in a control patient with hereditary spherocytosis [3].
• Similar to pancreatic cancers in the clinic, PK1 and PK8 cells carry constitutively active Ki-Ras and overexpress multiple receptor tyrosine kinases [4].
• Human pancreatic adenocarcinoma cell lines PK1 and PK8 are resistant to the clinically relevant chemotherapy agent gemcitabine [4].

High impact information on PKLR

• These data suggest that the paxillin association with PKL is essential for normal integrin-mediated cell spreading, and locomotion and that this interaction is necessary for the regulation of Rac activity during these events [5].
• Here, we demonstrate that the interaction of paxillin via its LD4 motif with the putative ARF-GAP paxillin kinase linker (PKL) (Turner et al., 1999), is critically involved in the regulation of Rac-dependent changes in the actin cytoskeleton that accompany cell spreading and motility [5].
• Hnf1alpha dependence of hnf4alpha, hnf4gamma, hnf3gamma, and two previously characterized distal targets (glut2 and pklr) is established only after differentiated cells arise during pancreatic embryonic development [6].
• A highly conserved haplotype at four markers flanking GBA (PKLR, D1S1595, D1S2721, and D1S2777) was observed on both the AJ chromosomes and the non-Jewish N370S chromosomes, suggesting the occurrence of a founder common to both populations [7].
• The intron sequences of the human L-type pyruvate kinase gene (PKLR) were determined by using primers selected from the known cDNA sequence [8].

Chemical compound and disease context of PKLR

• PK1 demonstrated antitumor activity in refractory cancers, no polymer-related toxicity, and proof of principle that polymer-drug conjugation decreases doxorubicin dose-limiting toxicities [9].

Biological context of PKLR

• Common variants in the PKLR are associated with increased risk of type 2 diabetes, but because of strong linkage disequilibrium between variants, the actual susceptibility allele may be in a different gene [10].
• Based on variability at the PKLR STRP and on the geographical distribution of LD, the expansion of the two main haplotypes may have predated the "Out of Africa" expansion of anatomically modern humans [11].
• We have established the functional importance of PKR-RE1, a necessary transcriptional regulatory element in the erythroid-specific promoter of the human pyruvate kinase gene (PKLR) [12].
• A splice mutation and a missense mutation were detected in the TRKA and PKLR genes from the homozygous proband, respectively [13].
• Trinucleotide repeat polymorphism at the PKLR locus [14].

Anatomical context of PKLR

• Isoforms that are expressed in the red cell, liver, pancreatic beta-cells, small intestine, and proximal renal tubule are encoded by the 12 exons of the PKLR gene, which maps to chromosome 1q23 [10].
• G-->T transition at cDNA nt 110 (K37Q) in the PKLR (pyruvate kinase) gene is the molecular basis of a case of hereditary increase of red blood cell ATP [15].
• This molecular phenotypic analysis of the null mutation in the PKLR gene provides evidence for a lack of M2PK in the mature RBCs of this patient and suggests that normal red cell functions and survival are achieved through a population of young erythroid cells released into the circulation in response to anemia [3].
• HNF1-alpha nevertheless occupies the endogenous glut2 and pklr promoters in both pancreatic islet and liver cells [16].
• These results suggest a GTP-Cdc42/GTP-Rac triggered multistep activation cascade leading to the stimulation of the adaptor function of PAK, which through interaction with PIX provokes a functional PKL PBS2-paxillin LD4 association and consequent recruitment to focal adhesions [17].

Associations of PKLR with chemical compounds

• Analysis of limited tryptic digests and cyanogen bromide cleavage fragments of PK1 and PK5 indicate that the subunits of the two isozymes are significantly different [18].
• M. racemosus hyphal cells grown on glutamic acid as the carbon source contained only the fastest electrophoretic form, designated PK1, while yeast cells grown on glucose contained only the slowest electrophoretic form, PK5 [18].
• Intermediate electrophoretic forms PK2, PK3, and PK4 as well as PK1 and PK5 were found in hyphal cells grown on media containing fructose or cellibiose [18].
• The serine protease domain of PK1 delta FE1X exhibits the amidolytic activity characteristic of wt t-PA [19].
• PK1 comprises doxorubicin covalently bound to N-(2-hydroxypropyl)methacrylamide copolymer by a peptidyl linker [9].

Other interactions of PKLR

• Binding to BPGM, PGAM2, and PKLR was not detected [20].
• Moreover, EMSA demonstrated that the CTGTC motif in both the PKLR and HK1 promoters mediates binding of the same protein [12].
• Life-threatening nonspherocytic hemolytic anemia in a patient with a null mutation in the PKLR gene and no compensatory PKM gene expression [3].
• The mRNA level was about five times lower than in normal controls, demonstrating that the PKLR gene transcription is severely affected, most probably because the -72A-->G point mutation disables the binding of the erythroid transcription factor GATA-1 to the GATA-A element [21].
• Deficiency of human erythrocyte isozyme (RPK) is, together with glucose-6-phosphate dehydrogenase deficiency, the most common cause of the nonspherocytic hemolytic anemia [22].

Analytical, diagnostic and therapeutic context of PKLR

• We describe a novel homozygous null mutation of the PKLR gene found in a girl with a prenatal diagnosis of PK deficiency [3].
• We analyzed the mutant enzymes of 10 unrelated patients with PKD, whose symptoms ranged from a mild, chronic hemolytic anemia to a severe anemia, by sequence analysis for the presence of alterations in the PKLR gene [23].
• Deletion was evidenced by a Sybergreen based quantitative real time polymerase chain reaction (PCR) and mapped using quantitative multiplex PCR of short fluorescent fragments spread along the whole sequence of the PKLR gene [24].
• Using in situ hybridization, we have mapped the human liver-type pyruvate kinase gene (PKL) to band q21 of chromosome 1 [25].
• Following storage in Tris-HCl (pH 7.4) buffer, a combination of HPLC and mass spectrometric analyses revealed that a significant amount of peptide bond cleavage occurred to produce the two peptides ArgProLys (RPK) and ArgProLysProGlnGln (RPKPQQ), with only a small amount of remaining intact SP [26].

References