Phosphotyrosine-containing lactate dehydrogenase is restricted to the nuclei of PC12 pheochromocytoma cells.
AUTOR(ES)
Zhong, X H
RESUMO
There are five lactate dehydrogenase (LDH) isoenzymes, composed of various combinations of two types of subunits. LDH-5, which contains only the LDH A subunit, is known to be present in both the cytoplasm and the nucleus, to act as a single-stranded DNA-binding protein possibly functioning in transcription and/or replication, and to undergo phosphorylation of tyrosine 238 in approximately 1% of the enzyme after cell transformation by certain tumor viruses. We have characterized LDH from wild-type PC12 pheochromocytoma cells and from a PC12 variant (MPT1) that exhibits altered lactate metabolism and altered expression of multiple genes. Wild-type and MPT1 cells contain different proportions of LDH isoenzymes, with LDH-5 being more predominant in wild-type cells than in the variant. A small fraction of LDH from PC12 cells contains phosphotyrosine. Approximately 99% of the total LDH activity is located in the cytoplasm, but all of the phosphotyrosine-containing LDH is located in the nucleus. Furthermore, essentially all of the nuclear LDH contains phosphotyrosine. These results suggest that tyrosine phosphorylation can affect its role in the nucleus.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=360877Documentos Relacionados
- Phosphotyrosine-containing proteins are concentrated in focal adhesions and intercellular junctions in normal cells.
- Rectification of acetylcholine-elicited currents in PC12 pheochromocytoma cells.
- Interleukin 1 expression is inducible by nerve growth factor in PC12 pheochromocytoma cells.
- Identification of a B2 bradykinin receptor expressed by PC12 pheochromocytoma cells.
- Specific neural and adrenal medullary antigens detected by antisera to clonal PC12 pheochromocytoma cells.