Genetics and Biochemistry Branch
NIDDK
Building 10, Room 9D-20
10 Center Drive MSC 1810
ph: 301-402-4770
fx: 301-496-9878
email: harris_bernstein@nih.gov
Our laboratory is interested in understanding how proteins are transported across biological membranes. In particular, we have been studying the role of the signal recognition particle (SRP) in the transport of proteins across the membrane of the [endoplasmic reticulum] (ER), which serves as the entry point for all proteins that travel through the secretory pathway. SRP is a [ribonucleoprotein] complex which binds to the "signal sequences" of proteins as they are being synthesized and then directs them to transport channels in the ER. SRP is found in all cell types and has been highly conserved from bacteria to man. In prokaryotes (which have no internal membranes) SRP is thought to facilitate transport of proteins across the cytoplasmic membrane.
We are currently investigating several problems related to SRP function. First, we are studying the mechanism by which a single subunit of SRP (the 54kd subunit, also called SRP54) binds to signal sequences with a high degree of specificity. This question is of particular interest because signal sequences vary greatly in their primary amino acid sequence. Second, we are trying to understand the significance of a [GTPase] activity associated with SRP54. Third, we are investigating the function of the RNA subunit of SRP. Finally, we are studying the function of SRP in prokaryotes, which differ from higher eukaryotes in that they also utilize SRP-independent mechanisms to target proteins to the cytoplasmic membrane.
Positions are available for post-doctoral fellows. Please address inquiries to Harris Bernstein at the above address.