Cytoplasmic ribonucleoprotein (RNP) bodies and their relationship to GW/P bodies

GW bodies (glycine- and tryptophan-rich cytoplasmic bodies; also known as mammalian processing (P) or Dcp-containing bodies) were described in 2002 when a human autoimmune serum was used to immunoscreen a HeLa expression library. Subsequently, many investigators have focused their attention on elucidating the components and functional relevance of this ribonucleoprotein (RNP)-containing cytoplasmic microdomain to cellular and molecular biology, developmental and pathological processes, and clinical practice. GW/P body components are now known to be involved in the post-transcriptional processing of messenger RNA (mRNA) through the RNA interference pathway, 5′ → 3′ mRNA degradation as well as mRNA transport and stabilization. It is currently thought that the relevant mRNA silencing and degrading factors are partitioned to these restricted cytoplasmic microdomains thus effecting post-transcriptional regulation and the prevention of accidental degradation of functional mRNA. Although much attention has focused on GW/P bodies, other cytoplasmic RNP bodies, which have highly specialized functions, interact or co-localize with components of GW/P bodies. These include neuronal transport RNP granules, stress granules, RNP-rich cytoplasmic germline granules or chromatoid bodies, sponge bodies, cytoplasmic prion protein-induced RNP granules, U bodies and TAM bodies. This review will focus on the similarities and differences of the various cytoplasmic RNP granules as an approach to understanding their functional relationships to GW/P bodies.