SP1: The Master Hub of Programmed Aging
Overview
SP1 (Sp1 Transcription Factor) is a zinc finger transcription factor that binds GC-rich motifs across an extraordinary number of gene promoters. Large-scale binding studies identify many thousands of SP1 target genes, and the Human Ageing Genomic Resources (GenAge) database lists SP1 as aging-associated, noting that it regulates ageing-related genes such as WRN and senescence genes like CDKN2A (p16). SP1 expression is downregulated in cellular senescence and is under DNA damage signaling regulation.
SP1 appeared among candidate aging genes in a preprint revision of Steve Horvath’s universal mammalian epigenetic clock paper but was dropped from the final published version, most likely for statistical stringency across hundreds of species rather than biological irrelevance. Independent analyses still find SP1 motifs enriched near Horvath clock CpG sites. Taken together with the mechanistic data reviewed here, SP1 emerges as arguably the single most connected “hub gene” in programmed aging.
This post catalogs the major pro‑aging pathways SP1 directly regulates: MAO-A/B (FAD sequestration and ROS), WRN (genome stability and puberty), LINE‑1 retrotransposons (inflammaging), TERT (telomerase), p16INK4a and p21 (senescence), caveolin‑1 (oxidative stress–induced senescence), SIRT1 (NAD+‑dependent deacetylation), IGF1R (growth/insulin signaling), nucleocytoplasmic trafficking, CD38 (NAD+ depletion), and lamin A.
