The aim of this mini-review is to give an update on the current developments concerning the IL-1 plasma membrane receptor complex and the modes of signal transduction through the plasma membrane. The mechanisms of signal generation at the cytosolic side of the plasma membrane will be summarized. Possible coupling mechanisms to down-stream signalling elements will be discussed, which result in the complex activation of transcription factors responsible for the cellular responses to IL-1. It is not the aim of this review to extensively summarize IL-1 induced cytosolic kinase cascades and activation of transcription factors.