Abstract
Challenge of human A375 melanoma cells with sodium arsenite induced the synthesis of stress proteins and stimulated [3H]mannose incorporation into a novel component migrating on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular mass of 14 kDa (designated M14). Enhanced M14 expression was elicited by heavy metals (zinc, copper, cadmium, and nickel), thiol-reactive agents (iodoacetamide and auranofin), and hyperthermia. The kinetics of M14 induction and recovery from stress were similar to those of the stress proteins, but M14 half-life was only 15 min. Incorporation of [3H]mannose into M14 was inhibited by tunicamycin but not by cycloheximide or actinomycin D. M14 was metabolically labeled with [32P]orthophosphate but not by [35S]methionine or [3H]asparagine. Further studies revealed that M14 was selectively soluble in chloroform/methanol/water (10:10:3) and sensitive to both endo-β-N-acetylglucosaminidase H digestion and mild acid hydrolysis. The latter released a water-soluble mannose-labeled moiety which eluted from Bio-Gel P-6 in a manner similar to Glc3Man9GlcNAc2. Together, these data suggest that M14 is a lipid-oligosaccharide intermediate of N-linked protein glycosylation and that enhanced expression of this class of molecule in response to chemical insults and hyperthermia is a newly described cellular reaction to stress.
Original language | English (US) |
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Pages (from-to) | 14815-14820 |
Number of pages | 6 |
Journal | Journal of Biological Chemistry |
Volume | 262 |
Issue number | 30 |
State | Published - 1987 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology