Signal recognition particle receptor (SRPR) is associated with the endoplasmic reticulum.  SRPR is a receptor for the signal recognition particle (SRP).  SRPR is a heterodimer with α and β subunits which contain a GTP-binding domain.  SRPR α subunit binds to SRP54 subunit of SRP complex.  SRPR β subunit is a transmembrane GTPase.  The bacterial SRPR is called FtsY.
- . Water molecules shown as red spheres.
 - .