Protein phosphatase 1 regulatory subunit 21 (PPP1R21)

Protein phosphatase 1 regulatory subunit 21 (PPP1R21) is a regulatory protein that functions as a co-factor for protein phosphatase 1 (PP1), a major serine/threonine phosphatase involved in a variety of cellular processes including cell division, glycogen metabolism, protein synthesis, and muscle contractility[2][5]. PPP1R21 is a component of the "FERRY" complex (Five-subunit Endosomal RAB5 and RNA/ribosome intermediary), which links mRNA and ribosomes to early endosomes via the small GTPase RAB5A[5]. This subunit mediates endosome-associated mRNA transport, likely affecting the localization and distribution of specific mRNAs in the cell[5]. Pathogenic variants in PPP1R21 cause an autosomal recessive neurodevelopmental disorder characterized by global developmental delay, hypotonia, brain abnormalities, and distinctive facial features (NEDHFBA)[2][5]. Loss of PPP1R21 function is associated with defects in vesicular trafficking and cytoskeletal architecture as well as upregulation of the ubiquitin–proteasome degradation system in human cells[2]. There is no current evidence that PPP1R21 is a direct therapeutic target, nor are there specific drugs targeting PPP1R21 described in the literature[2][4][5].

Other names

CCDC128FERRY2KLRAQ1Fy-2FLJ16566NEDHFBACoiled-coil domain-containing protein 128Ferry endosomal RAB5 effector complex subunit 2KLRAQ motif-containing protein 1coiled-coil domain containing 128