Src-regulated extracellular signal-related kinase and Syk-regulated c-Jun N-terminal kinase pathways act in conjunction to induce IL-1 synthesis in response to microtubule disruption in HL60 cells.

A microtubule reorganization is often observed during cellular contacts that are associated to IL-1 production. Here, we show that in HL60 cells, vincristine, a microtubule-disrupting agent that induces a strong production of IL-1, triggers the activation of both extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK-1). While ERK activation is rapid and transient, peaking at 10 min, the JNK1 activation is delayed and more sustained reaching a maximum at 2 h. ERK activation was blocked by CP 118556, indicating it is regulated by a Src-like kinase, while JNK1 was inhibited by piceatannol, revealing an upstream regulation by Syk. Each kind of the nonreceptor tyrosine kinase blockers efficiently inhibits the vincristine-induced IL-1 production and diminishes the level of IL-1 transcripts, indicating that the ERK and JNK pathways act coordinately to elicit the transcription of the IL-1 gene. Furthermore, we found that pertussis toxin, a blocker of Go/Gi proteins, abrogated the vincristine-induced activation of both Src and Syk. Our data support a model where the status of microtubule polymerization influences the activity of Go or Gi proteins that control, in turn, two independent Src/ERK and Syk/JNK1 cascades that are both necessary to sustain IL-1 synthesis.