ABSTRACT
During development, a handful of signals sculpt diverse tissue architectures. How the same signal produces different tissue/context-specific information and outcomes is poorly understood. We explored the basis that programs tissue-specific FGF dispersion and interpretation by cytoneme-mediated contact-dependent communication. Although a Drosophila FGF was thought to be freely secreted, we discovered that it is glypiated and GPI-anchored on the source cell surface, which inhibits non-specific secretion but facilitates tissue-specific cytoneme contact formation and contact-dependent release. For long-distance signaling, source and recipient cells extend FGF-containing and FGFR-containing cytonemes that contact and recognize each other by CAM-like receptor-ligand binding. FGF-FGFR binding reciprocally induces forward and reverse signaling in recipient and source cells, responses of which polarize their cytonemes toward each other to mutually self-sustain contacts. FGFR-bound FGF’s subsequent unanchoring hand-delivers FGF to receiving cytonemes and dissociates contacts. Thus, while cytonemes spatiotemporally control FGF dispersion/interpretation, FGF self-regulates its tissue-specific signaling by controlling cytonemes.
Competing Interest Statement
The authors have declared no competing interest.
