Can transcription factors function as cell-cell signalling molecules?

Recent data support the view that transcription factors - in particular, homeoproteins - can be transferred from cell to cell and have direct non-cell-autonomous (and therefore paracrine) activities. This intercellular transfer, based on atypical internalization and secretion, has important biotechnological consequences. But the real excitement stems from the physiological and developmental implications of this mode of signal transduction.