Protein translocation: common themes from bacteria to man

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• Protein transport across membranes is essential for cellular function in both eukaryotes and bacteria.
• The Sec61/SecYp complex serves as a fundamental protein translocation channel.
• Evolutionary conservation suggests a shared ancestral mechanism for protein transport.

Purpose of the Study:

• To highlight the relatedness of protein transport across the endoplasmic reticulum in eukaryotes and the cytoplasmic membrane in bacteria.
• To identify the core components and pathways involved in protein translocation.
• To investigate the roles of the Sec61/SecYp complex in different transport modes.

Main Methods:

• Comparative analysis of protein translocation machinery in prokaryotes and eukaryotes.
• Identification of conserved subunits within the Sec61/SecYp complex.
• Examination of the involvement of the Sec61/SecYp complex in co-translational and post-translational transport.

Main Results:

• Protein transport across the ER membrane (eukaryotes) and cytoplasmic membrane (bacteria) are evolutionarily related.
• The Sec61/SecYp complex is the central component of the translocation apparatus.
• At least two subunits of the Sec61/SecYp complex are conserved across species.
• The Sec61/SecYp complex participates in both co- and post-translational protein transport pathways.

Conclusions:

• The Sec61/SecYp complex is a highly conserved and essential machinery for protein translocation.
• Distinct additional components likely mediate the different modes of protein transport (co- vs. post-translational).
• Understanding this conserved mechanism provides insights into fundamental cellular processes.