The band-7 protein family comprises a diverse set of membrane-bound proteins characterised by the presence of a conserved domain, the band-7 domain, also known as SPFH or PHB domain [ (PUBMED:10542406) ]. The exact function of the band-7 domain is not known, but examples from animal and bacterial stomatin-type proteins demonstrate binding to lipids and the ability to assemble into membrane-bound oligomers that form putative scaffolds [ (PUBMED:24782879) ]. A variety of proteins belong to this family. These include the prohibitins, cytoplasmic anti-proliferative proteins and stomatin, an erythrocyte membrane protein. Bacterial HflC protein also belongs to this family.
Note: Band 4.1 and Band 7 proteins refer to human erythrocyte membrane proteins separated by SDS polyacrylamide gels and stained with coomassie blue [ (PUBMED:4326772) ].
Family alignment:
There are 67158 PHB domains in 67131 proteins in SMART's nrdb database.
Click on the following links for more information.
Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing PHB domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with PHB domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing PHB domain in the selected taxonomic class.
Literature (relevant references for this domain)
Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
Prohibitins regulate membrane protein degradation by the m-AAA protease in mitochondria.
Mol Cell Biol. 1999; 19: 3435-42
Display abstract
Prohibitins comprise a protein family in eukaryotic cells with potential roles in senescence and tumor suppression. Phb1p and Phb2p, members of the prohibitin family in Saccharomyces cerevisiae, have been implicated in the regulation of the replicative life span of the cells and in the maintenance of mitochondrial morphology. The functional activities of these proteins, however, have not been elucidated. We demonstrate here that prohibitins regulate the turnover of membrane proteins by the m-AAA protease, a conserved ATP-dependent protease in the inner membrane of mitochondria. The m-AAA protease is composed of the homologous subunits Yta10p (Afg3p) and Yta12p (Rca1p). Deletion of PHB1 or PHB2 impairs growth of Deltayta10 or Deltayta12 cells but does not affect cell growth in the presence of the m-AAA protease. A prohibitin complex with a native molecular mass of approximately 2 MDa containing Phb1p and Phb2p forms a supercomplex with the m-AAA protease. Proteolysis of nonassembled inner membrane proteins by the m-AAA protease is accelerated in mitochondria lacking Phb1p or Phb2p, indicating a negative regulatory effect of prohibitins on m-AAA protease activity. These results functionally link members of two conserved protein families in eukaryotes to the degradation of membrane proteins in mitochondria.
Disease (disease genes where sequence variants are found in this domain)
SwissProt sequences and OMIM curated human diseases associated with missense mutations within the PHB domain.
This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with PHB domain which could be assigned to a KEGG orthologous group, and not all proteins containing PHB domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.
