LLC-PK1 cell mutants in cAMP metabolism respond normally to phorbol esters

David A. Jans, Brian A. Hemmings

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Mutants of the pig kidney cell line, LLC-PK1, affected in cAMP metabolism, were examined for cAMP-dependent protein kinase (cAMP-PK) activity and for cAMP-mediated induction of urokinase-type plasminogen activator (uPA). The FIB4 and FIB6 mutant cell lines possessed about 10% parental levels of cAMP-PK activity and concomitantly reduced uPA production (10-20% parental) in response to calcitonin, forskolin and 8-bromo cAMP. The FIB1, FIB2 and FIB5 mutant cell lines had about 70% parental levels of cAMP-PK and the synthesis of uPA was 40-60% parental. Thus, cAMP-mediated induction of uPA showed a dependence on the absolute levels of cAMP-PK. However, uPA synthesis in response to phorbol-12-myristate-13-acetate by all of the mutants was similar to parental, which indicates that enzyme induction mediated by phorbol esters does not involve cAMP or cAMP-PK.

Original languageEnglish
Pages (from-to)127-131
Number of pages5
JournalFEBS Letters
Issue number1
Publication statusPublished - 1 Sept 1986
Externally publishedYes


  • cyclic AMP dependence
  • Enzyme induction
  • Protein kinase
  • Somatic cell mutant
  • Urokinase-type plasminogen activator

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