Negatively regulates signaling through the G-protein coupled thromboxane A2 receptor (TBXA2R) (By similarity). May be involved in mechanisms like programmed cell death, craniofacial development, patterning of the limbs, and formation of the left-right axis. Involved in the organization of apical junctions; the function is proposed to implicate a NPHP1-4-8 module. Does not seem to be strictly required for ciliogenesis (By similarity). Involved in establishment of planar cell polarity such as in cochlear sensory epithelium and is proposed to implicate stabilization of disheveled proteins (PubMed:22927466). Involved in regulation of proteasomal activity at the primary cilium probably implicating association with PSDM2 (PubMed:26150391). Interacts with NPHP4 and NPHP1; NPHP1, NPHP4 and RPGRIP1L are proposed to form a functional NPHP1-4-8 module localized to cell-cell contacts and the ciliary transition zone; NPHP4 mediates the interaction between NPHP1 and RPGRIP1L. Interacts with IQCB1; the interaction likely requires additional interactors (PubMed:21565611). Interacts with TBXA2R (via C-terminus), RPGR, NEK4. Interacts with NPHP4, INVS and DVL2; proposed to form a complex involved in DVL2 stabilization (By similarity). Interacts with PSMD2 (PubMed:26150391). In cultured renal cells, it localizes diffusely in the cytoplasm but, as cells approach confluence, it accumulates to basolateral tight junctions. Localizes to the ciliary transition zone. Ubiquitously expressed. Not found in heart and skin. Expression was detected throughout embryonic development as early as 8.5 dpc. Belongs to the RPGRIP1 family.