Prolyl 3-hydroxylase family member 4 (P3H4)

Prolyl 3-hydroxylase family member 4 (P3H4) is an endoplasmic reticulum (ER)-resident protein and a member of the Leprecan family, also known as endoplasmic reticulum protein SC65[2]. Unlike other prolyl 3-hydroxylases, P3H4 is believed to lack enzymatic activity and instead functions as a regulatory or structural component in collagen modification complexes[2]. It has been shown to be a direct substrate of the ER-phagy receptor CCPG1, which mediates selective removal of aberrant ER proteins[2]. P3H4 forms complexes with enzymes involved in collagen maturation, particularly influencing the hydroxylation of collagen lysine residues via complex formation with other prolyl 3-hydroxylases[2]. Studies indicate that P3H4 is linked to cancer biology; its overexpression correlates with poor prognosis and increased tumor progression in bladder and lung cancers[2]. Currently, P3H4 is not recognized as a druggable enzyme, receptor, or transporter, and there are no known approved drugs or small molecules that directly interact with it or target it therapeutically.

Other names

Endoplasmic reticulum protein SC65LEPREL4NOL55SC65NO55Leprecan-like protein 4Nucleolar autoantigen No55Synaptonemal complex protein SC65synaptonemal complex 65nucleolar autoantigen No55leprecan-like 4nucleolar autoantigen (55kD)nucleolar autoantigen, 55kDaprolyl 3-hydroxylase family member 4 (non-enzymatic)