Figure 5. Homo- and hetero-dimerisation of SmVKR. Requirement of Ca²⁺ and/or L-Arg for receptor dimerisation and kinase activation.

cRNAs encoding different tagged versions (Myc or V5) of SmVKR1 and SmVKR2 were injected in Xenopus oocytes. Oocytes were incubated for 5 h in ND96 medium with or without Ca²⁺ and L-Arg, as indicated. Membrane soluble extracts were immunoprecipitated (IP) by anti-V5 or anti-Myc antibodies and analysed by Western Blot (WB) with anti-V5, anti-Myc or anti-phosphotyrosine (pY20) antibodies. L-Arg and Ca²⁺ induce respectively the formation of active homodimers of SmVKR1 and SmVKR2. SmVKR1/SmVKR2 active heterodimers can be formed in the presence of L-Arg and Ca²⁺ (two bands of 170 kDa and 150 kDa corresponding respectively to SmVKR2 and SmVKR1 are labelled by anti-PY antibodies).