background:
Slc9a9 (Sodium/hydrogen exchanger 9) or NHE9 may act in electroneutral exchange of protons for Na(+) across membranes. Four isoforms of the Na+/H+ exchanger (NHE6-NHE9) are distributed to intracellular compartments in human cells. They are localized to Golgi and post-Golgi endocytic compartments as follows: mid- to trans-Golgi, NHE8; trans-Golgi network, NHE7; early recycling endosomes, NHE6; and late recycling endosomes, NHE9. The intracellular localization of the NHEs is established by the balance of transport in and out of the post-Golgi compartments as the dynamic membrane trafficking. Their in vivo function is to regulate the pH and monovalent cation concentration in these organelles.
Function:
May act in electroneutral exchange of protons for Na(+) across membranes. Involved in the effusion of Golgi luminal H(+) in exchange for cytosolic cations. Involved in organelle ion homeostasis by contributing to the maintenance of the unique acidic pH values of the Golgi and post-Golgi compartments in the cell.
Subcellular Location:
Late endosome membrane; Multi-pass membrane protein.
Tissue Specificity:
Ubiquitously expressed in all tissues tested. Expressed at highest levels in heart and skeletal muscle, followed by placenta, kidney, and liver. Expressed in the brain, in the medulla and spinal cord.
DISEASE:
Note=A chromosomal aberration involving SLC9A9 has been found in a family with early-onset behavioral/developmental disorder with features of attention deficit-hyperactivity disorder and intellectual disability. Inversion inv(3)(p14:q21). The inversion disrupts DOCK3 and SLC9A9.
Defects in SLC9A9 are a cause of susceptibility to autism type 16 (AUTS16) [MIM:613410]. Autism is a complex multifactorial, pervasive developmental disorder characterized by impairments in reciprocal social interaction and communication, restricted and stereotyped patterns of interests and activities, and the presence of developmental abnormalities by 3 years of age. Most individuals with autism also manifest moderate mental retardation. AUTS16 can be associated with epilepsy.
Similarity:
Belongs to the monovalent cation:proton antiporter 1 (CPA1) transporter (TC 2.A.36) family.
Database links:
Entrez Gene: 285195 Human
Entrez Gene: 36204 Mouse
Entrez Gene: 363115 Rat
Omim: 608396 Human
SwissProt: Q8IVB4 Human
SwissProt: Q8BZ00 Mouse
Unigene: 302257 Human
Unigene: 326125 Mouse
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
|
|
