Intact S49 mouse lymphoma cells were used as a model system to study the effects of cyclic AMP (CAMP) and its analogs on the phosphorylation of regulatory (R) subunit of type I CAMP-dependent protein kinase. Phosphorylation of R subunit was negligible in mutants deficient in adenylate cyclase; low l
Coexpression of mutant and wild type protein kinase in lymphoma cells resistant to dibutyryl cyclic AMP
β Scribed by Irma Lemaire; Philip Coffino
- Publisher
- John Wiley and Sons
- Year
- 1977
- Tongue
- English
- Weight
- 650 KB
- Volume
- 92
- Category
- Article
- ISSN
- 0021-9541
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β¦ Synopsis
Abstract
A mutant clone resistnat to dibutyryl cyclic AMP was isolated from S49 mouse lymphoma cells. The mutant expressed a form of cyclic AMPβdependent protein kinase distinguishable from wild type kinase by its decreased sensitivity to activation by cyclic AMP and its increased thermal lability. Hybrids formed between mutant and wild type cells were resistant to dibutyryl cyclic AMP and expresed both mutant and wild type activities in about equal amount. The parent mutant cells also appeared to express wild type kinase activity, but at a lower level. We conclude that wild type S49 cells have and expression two identical alleles for the regulatory subunit of protein kinase, one of which has undergone mutation in the mutant cells.
π SIMILAR VOLUMES
Structural lesions in CAMP-binding sites of regulatory (R) subunit of CAMPdependent protein kinase caused identical increases in apparent constants for cyclic nucleotide-dependent kinase activation in preparations from cells that were hemizygous or heterozygous for mutant R, subunit expression. No w