The function of ENSG00000172367 (NHERF4, NHERF family PDZ scaffold protein 4) is as follows. Acts as a regulatory protein that associates with GUCY2C and negatively modulates its heat-stable enterotoxin-mediated activation (PubMed:11950846). Stimulates SLC9A3 activity in the presence of elevated calcium ions (PubMed:19088451). {ECO:0000269|PubMed:11950846, ECO:0000269|PubMed:19088451}.