Structure and Activity of the Type VI Secretion System

Area of Science:

• Microbiology
• Molecular Biology
• Cell Biology

Background:

• The type VI secretion system (T6SS) is a sophisticated nanomachine found in many bacteria.
• It mediates inter-bacterial or bacterial-host interactions through effector protein delivery.

Purpose of the Study:

• To provide a comprehensive summary of the T6SS.
• To elucidate the structure, assembly, and mechanism of action of the T6SS.
• To review T6SS effector functions and their delivery processes.

Main Methods:

• Literature review and synthesis of existing research on T6SS.
• Analysis of structural and mechanistic data from various studies.
• Compilation of information on effector protein diversity and targeting.

Main Results:

• The T6SS comprises a baseplate, contractile sheath, inner tube, spike complex, and trans-envelope complex.
• Sheath contraction drives inner tube propulsion for effector delivery.
• Effectors are loaded into the inner tube or onto the spike complex for delivery to prokaryotic or eukaryotic cells.

Conclusions:

• The T6SS is a versatile secretion machine with a conserved yet adaptable mechanism.
• Understanding T6SS structure and function is crucial for deciphering bacterial pathogenesis and inter-microbial competition.
• Further research into T6SS effectors and their recruitment will reveal new biological insights.