Getting on target: The archaeal signal recognition particle
CHRISTIAN ZWIEB 1 and JERRY EICHLER 2,3
1 Department of Molecular Biology, University of Texas Health Science Center at Tyler, Tyler, TX 75708-3154, USA
2 Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel
3 Author to whom correspondence should be addressed ([email protected])
Received July 13, 2001; accepted November 9, 2001; published online November 21, 2001
Protein translocation begins with the efficient targeting of secreted and membrane proteins to complexes embedded within the membrane. In Eukarya and Bacteria, this is achieved through the interaction of the signal recognition particle (SRP) with the nascent polypeptide chain. In Archaea, homologs of eukaryal and bacterial SRP-mediated translocation pathway components have been identified. Biochemical analysis has revealed that although the archaeal system incorporates various facets of the eukaryal and bacterial targeting systems, numerous aspects of the archaeal system are unique to this domain of life. Moreover, it is becoming increasingly clear that elucidation of the archaeal SRP pathway will provide answers to basic questions about protein targeting that cannot be obtained from examination of eukaryal or bacterial models. In this review, recent data regarding the molecular composition, functional behavior and evolutionary significance of the archaeal signal recognition particle pathway are discussed.
protein targeting, protein translocation, ribonucleoprotein complex, RNA, signal sequence.