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Gene Review

PHB1  -  prohibitin subunit PHB1

Saccharomyces cerevisiae S288c

Synonyms: PHB, Prohibitin-1, YGR132C
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Disease relevance of PHB1


High impact information on PHB1

  • This complex is similar in size to the yeast complex formed by the homologues Phb1p and Phb2p [2].
  • 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 [3].
  • Phb2p, a homolog of the tumor suppressor protein prohibitin, was identified in a genetic screen for suppressors of the loss of Mdm12p, a mitochondrial outer membrane protein required for normal mitochondrial morphology and inheritance in Saccharomyces cerevisiae [4].
  • In otherwise wild-type genetic backgrounds, null mutations in PHB1 and PHB2 did not confer any obvious phenotypes [4].
  • These results provide the first evidence of a role for prohibitin in mitochondrial inheritance and in the regulation of mitochondrial morphology [4].

Biological context of PHB1

  • This loss of mitochondrial integrity was not seen in cells devoid of PHB1 but possessing an intact mitochondrial genome [5].
  • This may reflect an imbalance in the turnover of components of the respiratory chain in G0 cells, since the Phb1/2p complex is known to help stabilise these components [6].
  • Prohibitin proteins have been implicated in cell proliferation, ageing and the maintenance of mitochondrial integrity [6].
  • Prohibitin, which consists of two subunits PHB1 and PHB2, plays a role in cell-cycle progression, senescence, apoptosis, and maintenance of mitochondrial function in mammals and yeast [7].
  • Another gene postulated to effect senescence is PHB1, the yeast homologue of prohibitin [3], a rodent gene initially identified as a potential regulator of growth arrest and tumour suppressor [6-8] [8].

Anatomical context of PHB1

  • 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 [3].
  • Mitochondrial integrity is affected by the PHB1 and PHB2 genes, which encode inner mitochondrial membrane chaperones called prohibitins [9].
  • A second mammalian gene, encoding BAP37, a protein with sequence similarity to prohibitin, is thought to be involved in lymphocyte function [9] [8].
  • We further demonstrate that a deficiency in PHB proteins results in altered mitochondrial biogenesis in body wall muscle cells [10].
  • By using RNA-mediated gene inactivation, we show that PHB proteins are essential during embryonic development and are required for somatic and germline differentiation in the larval gonad [10].

Associations of PHB1 with chemical compounds

  • Synthetic lethal interaction of the mitochondrial phosphatidylethanolamine biosynthetic machinery with the prohibitin complex of Saccharomyces cerevisiae [11].
  • Deletion of PHB1 and PHB2 resulted in an increase of mitochondrial PtdEtn at 30 degrees C. On glucose media, phb1Delta psd1Delta and phb2Delta psd1Delta double mutants were rescued only for a limited number of generations by exogenous ethanolamine, indicating that a decrease of the PtdEtn level is detrimental for prohibitin mutants [11].
  • Finally, disruption of prohibitin function rendered the plants more susceptible to various oxidative stress-inducing reagents, including H(2)O(2), paraquat, antimycin A and salicylic acid [7].

Physical interactions of PHB1

  • A prohibitin complex with a native molecular mass of approximately 2 MDa containing Phb1p and Phb2p forms a supercomplex with the m-AAA protease [3].

Other interactions of PHB1

  • Membrane insertion involves binding of newly imported Phb1 to Tim8/13 complexes in the intermembrane space and is mediated by the TIM23-translocase [12].

Analytical, diagnostic and therapeutic context of PHB1


  1. Characterization of the plant homologue of prohibitin, a gene associated with antiproliferative activity in mammalian cells. Snedden, W.A., Fromm, H. Plant Mol. Biol. (1997) [Pubmed]
  2. Prohibitins act as a membrane-bound chaperone for the stabilization of mitochondrial proteins. Nijtmans, L.G., de Jong, L., Artal Sanz, M., Coates, P.J., Berden, J.A., Back, J.W., Muijsers, A.O., van der Spek, H., Grivell, L.A. EMBO J. (2000) [Pubmed]
  3. Prohibitins regulate membrane protein degradation by the m-AAA protease in mitochondria. Steglich, G., Neupert, W., Langer, T. Mol. Cell. Biol. (1999) [Pubmed]
  4. Prohibitin family members interact genetically with mitochondrial inheritance components in Saccharomyces cerevisiae. Berger, K.H., Yaffe, M.P. Mol. Cell. Biol. (1998) [Pubmed]
  5. Prohibitins and Ras2 protein cooperate in the maintenance of mitochondrial function during yeast aging. Kirchman, P.A., Miceli, M.V., West, R.L., Jiang, J.C., Kim, S., Jazwinski, S.M. Acta Biochim. Pol. (2003) [Pubmed]
  6. Loss of prohibitins, though it shortens the replicative life span of yeast cells undergoing division, does not shorten the chronological life span of G0-arrested cells. Piper, P.W., Bringloe, D. Mech. Ageing Dev. (2002) [Pubmed]
  7. Prohibitin is involved in mitochondrial biogenesis in plants. Ahn, C.S., Lee, J.H., Reum Hwang, A., Kim, W.T., Pai, H.S. Plant J. (2006) [Pubmed]
  8. The prohibitin family of mitochondrial proteins regulate replicative lifespan. Coates, P.J., Jamieson, D.J., Smart, K., Prescott, A.R., Hall, P.A. Curr. Biol. (1997) [Pubmed]
  9. Yeast replicative life span--the mitochondrial connection. Jazwinski, S.M. FEMS Yeast Res. (2004) [Pubmed]
  10. The mitochondrial prohibitin complex is essential for embryonic viability and germline function in Caenorhabditis elegans. Artal-Sanz, M., Tsang, W.Y., Willems, E.M., Grivell, L.A., Lemire, B.D., van der Spek, H., Nijtmans, L.G., Sanz, M.A. J. Biol. Chem. (2003) [Pubmed]
  11. Synthetic lethal interaction of the mitochondrial phosphatidylethanolamine biosynthetic machinery with the prohibitin complex of Saccharomyces cerevisiae. Birner, R., Nebauer, R., Schneiter, R., Daum, G. Mol. Biol. Cell (2003) [Pubmed]
  12. Formation of membrane-bound ring complexes by prohibitins in mitochondria. Tatsuta, T., Model, K., Langer, T. Mol. Biol. Cell (2005) [Pubmed]
  13. Prohibitin, a putative negative control element present in Pneumocystis carinii. Narasimhan, S., Armstrong, M., McClung, J.K., Richards, F.F., Spicer, E.K. Infect. Immun. (1997) [Pubmed]
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