Fig. 1.

Primary structure of PLCβ isozymes and splice variants. Numbers above the diagram correspond to domain boundaries in human PLCβ3, and all domain diagrams correspond to human isoforms, with the exception of PLCβ4b, which is from Rattus norvegicus. All identified PLCβ variants share the same catalytic core, which is the minimal fragment of PLCβ that hydrolyzes PIP₂, defined as the N terminus through the end of the C2 domain. The PLCβ isoforms differ most significantly in the length of the X–Y linker, whereas the splice variants reported for each isoform primarily vary the length and sequence of the CTD linker and extreme C terminus. Regions with sequences unique to the PLCβ1b and PLCβ4a splice variants are shown in pink.