Non-neuronal enolase is an endothelial hypoxic stress protein.

Abstract

The hypoxia-associated proteins (HAPs) are five cell-associated stress proteins (M(r) 34, 36, 39, 47, and 57) up-regulated in cultured vascular endothelial cells (EC) exposed to hypoxia. While hypoxic exposure of other cell types induces heat shock and glucose-regulated proteins, EC preferentially up-regulate HAPs. In order to identify the 47-kDa HAP, protein from hypoxic bovine EC lysates was isolated, digested with trypsin, and sequenced. Significant identity was found with enolase, a glycolytic enzyme. Western analyses confirmed that non-neuronal enolase (NNE) is up-regulated in hypoxic EC. Western analysis of subcellular fractions localized NNE primarily to the cytoplasm and confirmed that it was up-regulated 2.3-fold by hypoxia. Interestingly, NNE also appeared in the nuclear fraction of EC but was unchanged by hypoxia. Northern analyses revealed that NNE mRNA hypoxic up-regulation began at 1-2 h, peaked at 18 h, persisted for 48 h, and returned to base line after return to 21% O2 for 24 h. Hypoxia maximally up-regulated NNE mRNA levels 3.4-fold. While hypoxic up-regulation of NNE may have a protective effect by augmenting anaerobic metabolism, we speculate that enolase may contribute to EC hypoxia tolerance through one or more of its nonglycolytic functions.

• Authors: R M Aaronson, K K Graven, M Tucci, R J McDonald, H W Farber
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 270 Issue 46 Pg. 27752-7 (Nov 17 1995) ISSN: 0021-9258 [Print] United States
• PMID: 7499243 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Heat-Shock Proteins
• RNA, Messenger
• Phosphopyruvate Hydratase

Topics

• Amino Acid Sequence
• Animals
• Aorta
• Blotting, Western
• Cattle
• Cell Hypoxia
• Cell Nucleus (enzymology)
• Cells, Cultured
• Cytosol (enzymology)
• Electrophoresis, Polyacrylamide Gel
• Endothelium, Vascular (cytology, enzymology)
• Gene Expression Regulation, Enzymologic
• Heat-Shock Proteins (biosynthesis, chemistry)
• Humans
• Kinetics
• Molecular Sequence Data
• Phosphopyruvate Hydratase (biosynthesis, chemistry)
• Pulmonary Artery
• RNA, Messenger (analysis, biosynthesis)
• Sequence Homology, Amino Acid
• Time Factors