Uncharacterized family; SPFH (stomatin, prohibitin, flotillin, and HflK/C) superfamily
This model summarizes an uncharacterized family of proteins similar to stomatin, prohibitin, flotillin, HflK/C (SPFH) and podocin. The conserved domain common to the SPFH superfamily has also been referred to as the Band 7 domain. Many superfamily members are associated with lipid rafts. Individual proteins of the SPFH superfamily may cluster to form membrane microdomains which may in turn recruit multiprotein complexes. Microdomains formed from flotillin proteins may in addition be dynamic units with their own regulatory functions. Flotillins have been implicated in signal transduction, vesicle trafficking, cytoskeleton rearrangement and are known to interact with a variety of proteins. Stomatin interacts with and regulates members of the degenerin/epithelia Na+ channel family in mechanosensory cells of Caenorhabditis elegans and vertebrate neurons and participates in trafficking of Glut1 glucose transporters. Prohibitin may act as a chaperone for the stabilization of mitochondrial proteins. Prokaryotic HflK/C plays a role in the decision between lysogenic and lytic cycle growth during lambda phage infection. Flotillins have been implicated in the progression of prion disease, in the pathogenesis of neurodegenerative diseases such as Parkinson's and Alzheimer's disease, and in cancer invasion and metastasis. Mutations in the podocin gene give rise to autosomal recessive steroid resistant nephritic syndrome.