SRP54
Developmental stage
up-regulated during granulocytic differentiation.
Domain
The NG domain, also named G domain, is a special guanosine triphosphatase (GTPase) domain, which binds GTP and forms a guanosine 5'-triphosphate (GTP)-dependent complex with a homologous NG domain in the SRP receptor subunit SRPRA (PubMed:34020957). The two NG domains undergo cooperative rearrangements upon their assembly, which culminate in the reciprocal activation of the GTPase activity of one another (PubMed:34020957). SRP receptor compaction upon binding with cargo-loaded SRP and GTPase rearrangement drive SRP-mediated cotranslational protein translocation into the ER (PubMed:34020957).
The M domain binds the 7SL RNA in presence of SRP19 and binds the signal sequence of presecretory proteins.
Function
Component of the signal recognition particle (SRP) complex, a ribonucleoprotein complex that mediates the cotranslational targeting of secretory and membrane proteins to the endoplasmic reticulum (ER) (PubMed:34020957). As part of the SRP complex, associates with the SRP receptor (SR) component SRPRA to target secretory proteins to the endoplasmic reticulum membrane (PubMed:34020957). Binds to the signal sequence of presecretory proteins when they emerge from the ribosomes (PubMed:34020957). Displays basal GTPase activity, and stimulates reciprocal GTPase activation of the SR subunit SRPRA (PubMed:28972538, PubMed:34020957). Forms a guanosine 5'-triphosphate (GTP)-dependent complex with the SR subunit SRPRA (PubMed:34020957). SR compaction and GTPase mediated rearrangement of SR drive SRP-mediated cotranslational protein translocation into the ER (PubMed:34020957). Requires the presence of SRP9/SRP14 and/or SRP19 to stably interact with RNA (By similarity). Plays a role in proliferation and differentiation of granulocytic cells, neutrophils migration capacity and exocrine pancreas development (PubMed:28972538, PubMed:29914977).
Involvement in disease
Neutropenia, severe congenital 8, autosomal dominant
SCN8
A form of severe congenital neutropenia, a disorder of hematopoiesis characterized by maturation arrest of granulopoiesis at the level of promyelocytes with peripheral blood absolute neutrophil counts below 0.5 x 10(9)/l and early onset of severe bacterial infections.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the GTP-binding SRP family. SRP54 subfamily.
Cellular localization
- Nucleus speckle
- Cytoplasm
- Endoplasmic reticulum
Alternative names
Signal recognition particle subunit SRP54, Signal recognition particle 54 kDa protein, SRP54