Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.2.13 (aldolase)
 3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tyrosine specific protein kinase activity was determined in 70 specimens of the human mammary gland. These included 28 cancers of the breast, 21 benign breast diseases, and 21 normal breast tissues. We measured tyrosine kinase activity in the cytosol fraction and in the membrane fraction of the homogenates. In addition cytosolic aldolase activity was measured. Tyrosine kinase activity was determined using poly(glutamic acid:tyrosine = 4:1) as an artificial substrate. Cancers of the breast exhibited considerable higher tyrosine kinase activities in both cytosol and membrane fractions, compared to benign breast tumors (P less than or equal to 0.001). Benign tumors demonstrated increased activities in cytosol in comparison to normal breast tissues (P less than 0.001). Furthermore, there appears to be a strong association of an enhanced expression of activity of tyrosine kinase in cytosol of primary carcinomas and early systemic relapse. In combination with aldolase activity a nearly complete discrimination is achieved between malignant specimens on one hand and benign and normal tissues on the other.
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PMID:Tyrosine kinase activity in breast cancer, benign breast disease, and normal breast tissue. 291 Apr 71

A structural basis for activation and substrate specificity of src tyrosine kinases, and regulation of protein-protein association by tyrosine phosphorylation is described. Lyn, a src-family tyrosine kinase, recognizes and phosphorylates the immunoreceptor tyrosine-based activation motif, ITAM, a critical component in transmembrane signal transduction in hemopoietic cells. The structure of an ITAM peptide substrate bound to an active form of Lyn tyrosine kinase was determined by high-resolution NMR, and a model of the complex was generated using the crystallographic structure of Lck, a closely related Src-family kinase. The results provide a rationale for the conserved ITAM residues and specificity of Lyn, and suggest that substrate plays a role in stabilizing the kinase conformation optimal for catalysis. It is our hope that the Lck-ITAM peptide model complex will be useful in aiding structure-based drug design efforts that target substrate binding determinants in the design. Concerning the regulation of protein-protein association, we report on a complex between erythrocyte band 3 and two glycolytic enzymes, aldolase and glyceraldehyde-3-phosphate dehydrogenase. The formation of this complex is negatively regulated by tyrosine phosphorylation of band 3 by p72syk tyrosine kinase. In red blood cells, this association results in a decrease in glycolysis due to competitive inhibition of the glycolytic enzymes. The structure of band 3 recognized by the glycolytic enzymes was determined by solution NMR, and found to be a loop structure with tyrosine centrally positioned and excluded from intermolecular contact. This phosphorylation sensitive interaction, or PSI, loop may be the basis of a general mechanism for negative regulation through tyrosine phosphorylation.
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PMID:NMR structure of phospho-tyrosine signaling complexes. 1039 26

Notwithstanding the numerous drugs available for liver cancer, emerging evidence suggests that chemotherapeutic resistance is a significant issue. HGF and its receptor MET play critical roles in liver carcinogenesis and metastasis, mainly dependent on the activity of receptor tyrosine kinase. However, for unknown reasons, all HGF-MET kinase activity-targeted drugs have failed or have been suspended in clinical trials thus far. Macroautophagy/autophagy is a protective 'self-eating' process for resisting metabolic stress by recycling obsolete components, whereas the impact of autophagy-mediated reprogrammed metabolism on therapeutic resistance is largely unclear, especially in liver cancer. In the present study, we first observed that HGF stimulus facilitated the Warburg effect and glutaminolysis to promote biogenesis in multiple liver cancer cells. We then identified the pyruvate dehydrogenase complex (PDHC) and GLS/GLS1 as crucial substrates of HGF-activated MET kinase; MET-mediated phosphorylation inhibits PDHC activity but activates GLS to promote cancer cell metabolism and biogenesis. We further found that the key residues of kinase activity in MET (Y1234/1235) also constitute a conserved LC3-interacting region motif (Y1234-Y1235-x-V1237). Therefore, on inhibiting HGF-mediated MET kinase activation, Y1234/1235-dephosphorylated MET induced autophagy to maintain biogenesis for cancer cell survival. Moreover, we verified that Y1234/1235-dephosphorylated MET correlated with autophagy in clinical liver cancer. Finally, a combination of MET inhibitor and autophagy suppressor significantly improved the therapeutic efficiency of liver cancer in vitro and in mice. Together, our findings reveal an HGF-MET axis-coordinated functional interaction between tyrosine kinase signaling and autophagy, and establish a MET-autophagy double-targeted strategy to overcome chemotherapeutic resistance in liver cancer. Abbreviations: ALDO: aldolase, fructose-bisphosphate; CQ: chloroquine; DLAT/PDCE2: dihydrolipoamide S-acetyltransferase; EMT: epithelial-mesenchymal transition; ENO: enolase; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GLS/GLS1: glutaminase; GLUL/GS: glutamine-ammonia ligase; GPI/PGI: glucose-6-phosphate isomerase; HCC: hepatocellular carcinoma; HGF: hepatocyte growth factor; HK: hexokinase; LDH: lactate dehydrogenase; LIHC: liver hepatocellular carcinoma; LIR: LC3-interacting region; PDH: pyruvate dehydrogenase; PDHA1: pyruvate dehydrogenase E1 alpha 1 subunit; PDHX: pyruvate dehydrogenase complex component X; PFK: phosphofructokinase; PK: pyruvate kinase; RTK: receptor tyrosine kinase; TCGA: The Cancer Genome Atlas.
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PMID:The HGF-MET axis coordinates liver cancer metabolism and autophagy for chemotherapeutic resistance. 3078 11