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| MAP KINASE IS CONSTITUTIVELY ACTIVATED IN GIP2 AND SRC TRANSFORMED RAT-1A FIBROBLASTS |
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| Author(s): GUPTA SK, GALLEGO C, JOHNSON GL, HEASLEY LE |
| Source: JOURNAL OF BIOLOGICAL CHEMISTRY Volume: 267 Issue: 12 Pages: 7987-7990 Published: APR 25 1992 |
| Times Cited: 221 References: 35 |
| Abstract: Rat 1a fibroblasts transformed by the G(i2) oncogene, gip2, exhibit a constitutively elevated mitogen-activated protein (MAP) kinase activity that correlates with enhanced tyrosine phosphorylation of the p42 MAP kinase polypeptide. The MAP kinase activity in gip2 transformed cells is 50-60% of the pertussis toxin-sensitive, thrombin-stimulated activity observed in wild-type Rat 1a cells. A similar activation of MAP kinase is observed in src but not ras or raf transformed Rat 1a cells, indicating that the persistent MAP kinase activity results from the action of the specific oncoprotein and is not the consequence of cellular transformation. The enhanced transactivation function of c-Jun characteristic of the transformed phenotype, measured using a collagenase promoter-CAT reporter gene, is observed in gip2, src, ras, and raf transformed Rat 1a cells. The regulatory networks controlled by the four transforming oncogenes therefore alter the activity of specific transcription factors, but only gip2 and src constitutively activate MAP kinase. The findings demonstrate that the catalytic activity of growth factor-regulated cytoplasmic kinases are selectively and stably activated as a consequence of specific oncogene expression. |
| Document Type: Note |
| Language: English |
Addresses:
1. NATL JEWISH CTR IMMUNOL & RESP MED, DIV BASIC SCI, 1400 JACKSON ST, DENVER, CO 80206 USA
2. UNIV COLORADO, SCH MED, DEPT PHARMACOL, DENVER, CO 80262 USA
3. UNIV COLORADO, SCH MED, DEPT MED, DIV RENAL, DENVER, CO 80262 USA |
| Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 |
| Subject Category: Biochemistry & Molecular Biology |
| IDS Number: HQ185 |
| ISSN: 0021-9258 |
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| | | | | | | | | Record from Web of Science® | | | | | | | | | |