Praja ring finger ubiquitin ligase 1 (PJA1)

Praja ring finger ubiquitin ligase 1 (PJA1) is a RING-type E3 ubiquitin-protein ligase that catalyzes the addition of ubiquitin to substrate proteins, targeting them for proteasomal degradation[1][2][3][7]. PJA1 regulates protein stability in multiple biological contexts, particularly in bone and neural development, where it modulates transcriptional regulators and aggregation-prone proteins. For example, PJA1 controls Dlx5-dependent osteoblast transcription through interaction with Dlxin-1 and degrades polycomb repressive complex 2 subunits, modulating developmental gene repression[1]. In the nervous system, PJA1 clears abnormal protein aggregates implicated in amyotrophic lateral sclerosis and Huntington’s disease[1]. PJA1 influences cancer biology by degrading tumor suppressor proteins, affecting cell proliferation, invasion, apoptosis, and chemoresistance mechanisms, with context-dependent tumor-promoting or suppressing activities[1]. It is encoded on the human X chromosome and displays high expression in neural tissues. No approved drugs currently directly target PJA1, though its enzymatic activity makes it a candidate for pharmacological modulation in oncology and neurodegeneration[1][2][3].

Other names

PRAJA1RNF70Praja1FLJ11830RING finger protein 70RING-type E3 ubiquitin transferase Praja-1Neurodap1MAGED1-ubiquitin-protein ligase

Drugs targeting PJA1 would likely act by modulating its E3 ubiquitin ligase activity, thereby affecting proteasomal degradation of specific substrate proteins, with downstream effects on oncogenic or neurodegenerative pathways[1][7].