Hi Rok,

The answer is 'yes' and 'no': take a look at the review of Pereira et al. (2013) https://academic.oup.com/femsre/article/37/2/156/623107/AI-2-mediated-signalling-in-bacteria.

Authors claim that "although the signal synthase, corresponding biosynthetic pathway and chemical products are the same in every AI-2-producing bacterium tested thus far, these studies demonstrate that the molecule ultimately detected by these bacteria can differ". There are a few intermediates and their derivatives which apparently also bind to receptors, thus opening the possiblity that other (closely related) molecules could serve as signals. There might be some update on this in the more recent literature, but this is not really my narrow field, so I hope you will get more hints on this.

Best regards,

Marko