| Attribute | Summary |
|---|---|
| Protein name | Mitochondrial prohibitin complex protein 1; Prohibitin-1 (PHB-1) (pqac-00000002, pqac-00000037) |
| Gene name | phb-1; ORF Y37E3.9 (verified against UniProt target specification; functional literature on C. elegans prohibitin complex is consistent with this identity) (pqac-00000002, pqac-00000004) |
| UniProt ID | Q9BKU4 (from target specification; literature supports the corresponding C. elegans prohibitin-1 identity and function) (pqac-00000002, pqac-00000004) |
| Organism | *Caenorhabditis elegans* (pqac-00000000, pqac-00000001) |
| Protein family | Prohibitin family; member of the SPFH/Band_7 superfamily of membrane scaffold proteins (pqac-00000005, pqac-00000016) |
| Key domains | Conserved PHB/SPFH (Band_7) domain with N-terminal hydrophobic/transmembrane anchor and C-terminal coiled-coil region mediating PHB-1/PHB-2 assembly (pqac-00000001, pqac-00000002) |
| Molecular weight | PHB-1 is ~32 kDa; PHB-2 is ~34 kDa (pqac-00000001, pqac-00000035) |
| Subcellular localization | Predominantly mitochondrial inner membrane (IMM), with the complex projecting into the intermembrane space/crista lumen; localization within crista-associated membrane regions is implicated in membrane organization (pqac-00000001, pqac-00000007, pqac-00000034) |
| Complex partners | Obligatory heterocomplex with PHB-2; functionally associated with m-AAA proteases, OXPHOS/ATP synthase components, OPA1/cristae machinery, ATAD3/nucleoid-associated factors, and lipid homeostasis pathways (pqac-00000003, pqac-00000016, pqac-00000017, pqac-00000040) |
| Complex stoichiometry | In C. elegans and earlier models, a ~1 MDa ring-like assembly of ~12–16 PHB-1/PHB-2 heterodimers was proposed; recent in situ human cryo-ET instead resolved a bell-shaped 11-subunit alternating PHB1/PHB2 assembly, refining structural understanding of prohibitin scaffolds (pqac-00000001, pqac-00000035, pqac-00000031, pqac-00000032) |
| Primary molecular function | Membrane-bound scaffold/chaperone rather than enzyme or transporter; stabilizes newly synthesized/assembled IMM proteins, cooperates with m-AAA proteases in membrane protein quality control, helps organize lipid microenvironments, and supports cristae architecture and respiratory chain integrity (pqac-00000016, pqac-00000018, pqac-00000020, pqac-00000022) |
| Key signaling pathway interactions: IIS/DAF-2 | PHB depletion shortens lifespan in wild type but extends lifespan in metabolically compromised animals such as *daf-2* mutants; PHB influences lipid remodeling, TAG/yolk homeostasis, and ER stress in an insulin-signaling-dependent manner (pqac-00000010, pqac-00000011, pqac-00000012) |
| Key signaling pathway interactions: TORC2/SGK-1 | SGK-1 is a major downstream determinant of the prohibitin longevity phenotype; PHB depletion extends lifespan in *sgk-1* and *rict-1* mutants, suppresses their mitochondrial and lipogenesis defects, and functionally links PHB to mTORC2-SGK-1 control of mitochondrial homeostasis (pqac-00000023, pqac-00000024, pqac-00000027, pqac-00000029) |
| Key signaling pathway interactions: UPRmt/ATFS-1 | PHB depletion robustly induces the mitochondrial unfolded protein response (UPRmt) in wild type; UPRmt behavior is context dependent in IIS/TORC2 mutants, and ATFS-1-dependent mitochondrial stress signaling contributes to longevity outcomes in PHB-deficient backgrounds (pqac-00000006, pqac-00000008, pqac-00000009, pqac-00000023) |
| Lifespan effects | Depletion of prohibitin shortens wild-type lifespan but extends lifespan in several metabolically compromised backgrounds including *daf-2*, *sgk-1*, and *rict-1* mutants; this is one of the defining context-dependent phenotypes of the PHB complex in *C. elegans* aging biology (pqac-00000012, pqac-00000023, pqac-00000025, pqac-00000030) |
| Essential cellular processes | Embryonic viability, germline function, mitochondrial morphogenesis, cristae maintenance, respiratory chain/OXPHOS biogenesis, mitochondrial proteostasis, lipid homeostasis, nucleoid/mtDNA organization, and mitochondrial quality control; PHB-2 additionally serves as an IMM mitophagy receptor via LC3 interaction, whereas PHB-1 participates in the heterocomplex that supports these functions (pqac-00000000, pqac-00000003, pqac-00000040, pqac-00000041) |


*Table: This table summarizes the core identity, localization, molecular role, pathway interactions, and phenotypic consequences of PHB-1/prohibitin-1 in *C. elegans*. It is useful as a compact reference linking the prohibitin complex’s structural role in mitochondria to its context-dependent effects on metabolism, stress signaling, and longevity.*