This protein appears to be a member of a somewhat larger structural family conserved in Firmicutes. The 3D structure is available for one protein, CPF_1278, which has been labelled a putative lipoprotein. CPF_1278 displays structural similarity to the N-terminal domain of YycH, which plays a role in signal transduction and is found immediately downstream of the essential histidine kinase YycG. YycG forms a two-component system together with its cognate response regulator YycF. YycH functions as a modulator of YycG activity, possibly by interacting with YchI. All three molecules (YchG, YchH, and YchI) have been characterized as membrane proteins, and they may be able to form homodimers.