Bacillus subtilis YqjG is required for genetic competence development

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• The Oxa1/Alb3/YidC protein family is crucial for membrane protein biogenesis.
• Bacillus subtilis possesses two YidC homologs: SpoIIIJ and YqjG, with overlapping but distinct functions.
• SpoIIIJ is essential for sporulation, a function not complemented by YqjG.

Purpose of the Study:

• To investigate the complementary roles of SpoIIIJ and YqjG in Bacillus subtilis.
• To elucidate the specific functions of YqjG in membrane protein assembly and other cellular processes.
• To understand the impact of SpoIIIJ and YqjG deficiency on cellular functions, including F(1)F(O) ATP synthase assembly and genetic competence.

Main Methods:

• Comparative analysis of membrane proteomes in Bacillus subtilis strains lacking SpoIIIJ, YqjG, or both.
• Functional assays to assess membrane protein insertion, folding, and assembly.
• Investigation of F(1)F(O) ATP synthase assembly defects.
• Evaluation of genetic competence development in mutant strains.

Main Results:

• SpoIIIJ and YqjG exhibit complementary functions in membrane protein insertion and assembly.
• Cells lacking both SpoIIIJ and YqjG show reduced levels of F(1)F(O) ATP synthase due to impaired F(1)-domain assembly onto the F(0)-domain.
• YqjG plays a specific, previously unrecognized role in facilitating genetic competence development in Bacillus subtilis.

Conclusions:

• SpoIIIJ and YqjG are essential for efficient membrane protein biogenesis in Bacillus subtilis, with distinct contributions.
• The assembly of the F(1)F(O) ATP synthase complex is critically dependent on the coordinated action of SpoIIIJ and YqjG.
• YqjG has a novel and specific function in promoting genetic competence, highlighting its multifaceted role beyond general membrane protein insertion.