Rhomboid_N is the N-terminal cytoplasmic domain of the rhomboid intra-membraneous serine protease, otherwise known as Peptidase_S54, Pfam:PF01694. This N-terminal domain has similarity to other GlnB-like domains, some of which appear to have a binding role, eg to peptidoglycan. It is not clear exactly what the function of this domain is in the protease, but its presence is critical for maintaining a catalytically competent state for the protein [1].

1: Activity-based protein profiling of the Escherichia coli GlpG rhomboid protein delineates the catalytic core. Sherratt AR, Blais DR, Ghasriani H, Pezacki JP, Goto NK; Biochemistry. 2012;51:7794-7803. PMID:22963263