Acts as a regulator of the tubular endoplasmic reticulum (ER) network by modulating intracellular calcium homeostasis. Mechanistically, stimulates PKD2 calcium-dependent activity (By similarity). Suppresses the RTN3/4-induced formation of the ER tubules . Positively regulates PERK-mediated and IRE1-mediated unfolded protein response signaling . Plays an essential role in VEGF-mediated release of Ca(2+) from ER stores during angiogenesis . Also plays a role in the modulation of innate immune signaling through the cGAS-STING pathway by interacting with RNF26 . Participates in lipid metabolism by acting as a downstream effector of the pyruvate kinase/PKM. Forms a complex with RNF5 to facilitate polyubiquitination and subsequent degradation of SCAP on the ER membrane .
Subcellular locations: Endoplasmic reticulum membrane, Melanosome, Nucleus envelope
Identified by mass spectrometry in melanosome fractions from stage I to stage IV. Co-localizes with RTN4 at the ER sheets.
Prostate cancer and several cancer cell lines (at protein level). Widely expressed. Expressed at higher levels in endocrine-resistant breast cancer cells as compared to endocrine-sensitive breast cancer cells. Expressed at higher levels in early recurrence breast cancer tissues as compared to non-recurrent breast tumors.