Optical　manipulation　appears　to　be　a　powerful　tool　for　spatiotemporally　controlling　a　variety　of　cellular　functions.　Herein,　a　photocontrolled　DNA　assembly　approach　is　described　which　enables　light-induced　activation　of　cellular　signal　transduction　by　triggering　protein　dimerization　(c-Met　signalling　in　this　case).　Three　kinds　of　DNA　probes　are　designed,　including　a　pair　of　receptor　recognition　probes　with　adaptors　and　a　blocker　probe　with　a　photocleavable　linker　(PC-linker).　By　implementing　PC-linkers　in　blocker　probes,　the　designed　DNA　probes　response　to　light　irradiation,　which　then　induces　the　assembly　of　receptor　recognition　probes　through　adaptor　complementing.　Consequently,　light-mediated　DNA　assembly　promotes　the　dimerization　of　c-Met　receptors,　resulting　in　activation　of　c-Met　signalling.　It　is　demonstrated　that　the　proposed　photocontrolled　DNA　assembly　approach　is　effective　for　regulating　c-Met　signalling　and　modulating　cellular　behaviours,　such　as　cell　proliferation　and　migration.　Therefore,　this　simple　approach　may　offer　a　promising　strategy　to　manipulate　cell　signalling　pathways　precisely　in　living　cells.　©　2018　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim