17q25.1

EBP50,NHERF,NHERF-1,NHERF1,NPHLOP2

Cancer progression

There is growing evidence SLC9A3R1 plays an important role in cancer progression. SLC9A3R1 functions as an adaptor protein to control cell transformation. In addition, recent evidence suggests that SLC9A3R1 has a dual role either acting as a tumor suppressor when it is localized as the cell membrane or as an oncogenic protein when it is localized in the cytoplasm (Georgescu et al., 2008).

Glioblastoma

The invasive nature of glioblastoma multiforme presents a clinical problem rendering tumors incurable by conventional treatment modalities such as surgery, ionizing radiation, and temozolomide.
SLC9A3R1 has been implicated to play a role in sustaining glioma cell migration and invasion. SLC9A3R1 has been shown to be over-expressed in invading glioma cells as compared to the tumor core (Kislin et al., 2009).

Breast cancer

Increased cytoplasmic expression of SLC9A3R1 in breast tumors suggests a key role of its localization and compartmentalization in defining cancerogenesis, progression, and invasion. SLC9A3R1 overexpression has been associated with increasing tumor cytohistological grade, aggressive clinical behavior, unfavorable prognosis, and increased tumor hypoxia. Moreover, SLC9A3R1 co-localizes with the oncogenic receptor HER2/neu in HER2/neu-overexpressing carcinoma and in distant metastases (Mangia et al., 2009).
The switch from apical membranous to cytoplasmic expression is compatible with a dual role for NHERF1 as a tumour suppressor or tumour promoter dependent on its subcellular localization (Georgescu et al., 2008).

Cystic fibrosis

The inherited disease cystic fibrosis is one of the most common chronic lung diseases in children and young adults and may lead to an early death.
Cystic fibrosis transmembrane regulator (CFTR) functions as a cAMP-regulated chloride channel, and mutations in CFTR are contributory in cystic fibrosis. CFTR contains a C-terminal SLC9A3R1 consensus sequence affording the two proteins to bind with high affinity. Recent experiments have postulated two roles for SLC9A3R1 in CFTR function. Guggino, Stanton, and coworkers have proposed that NHERF functions as a membrane retention signal for CFTR (Moyer et al., 1999).
Raghuram et al. suggest that SLC9A3R1 facilitates the dimerization of CFTR leading to its full expression of chloride channel activity (Raghuram et al., 2001).
Lastly, ss2-adrenoceptors have been shown to physically interact with CFTR Na+/H+ Exchanger Regulatory Factor 1 SLC9A3R1 protein. This function of SLC9A3R1 could be a new therapeutic target in CF patients to facilitate the trafficking of mutated CFTR to plasma membrane (Bossard et al., 2011).

Hypophosphatemia and nephrolithiasis

SLC9A3R1 plays an important role in tumor phosphorous transport. Inactivating missense mutations in SLC9AR1 have been identified in patients with hypercalciuria and neprolithiasis (Karim et al., 2008).