BioChem - DOS

Tuberculostearic Acid Controls Mycobacterial Membrane Compartmentalization

mBio

Prithviraj, Malavika; Kado, Takehiro; Mayfield, Jacob A.; Young, David C.; Huang, Annie D.; Motooka, Daisuke; Nakamura, Shota; Siegrist, M. Sloan; Moody, D. Branch; Morita, Yasu S.

<P><B>ABSTRACT</B></P><P>The intracellular membrane domain (IMD) is a laterally discrete region of the mycobacterial plasma membrane, enriched in the subpolar region of the rod-shaped cell. Here, we report genome-wide transposon sequencing to discover the controllers of membrane compartmentalization in Mycobacterium smegmatis. The putative gene <I>cfa</I> showed the most significant effect on recovery from membrane compartment disruption by dibucaine. Enzymatic analysis of Cfa and lipidomic analysis of a <I>cfa</I> deletion mutant (&Delta;<I>cfa</I>) demonstrated that Cfa is an essential methyltransferase for the synthesis of major membrane phospholipids containing a C<SUB>19:0</SUB> monomethyl-branched stearic acid, also known as tuberculostearic acid (TBSA). TBSA has been intensively studied due to its abundant and genus-specific production in mycobacteria, but its biosynthetic enzymes had remained elusive. Cfa catalyzed the <I>S</I>-adenosyl-<SMALL>L</SMALL>-methionine-dependent methyltransferase reaction using oleic acid-containing lipid as a substrate, and &Delta;<I>cfa</I> accumulated C<SUB>18:1</SUB> oleic acid, suggesting that Cfa commits oleic acid to TBSA biosynthesis, likely contributing directly to lateral membrane partitioning. Consistent with this model, &Delta;<I>cfa</I> displayed delayed restoration of subpolar IMD and delayed outgrowth after bacteriostatic dibucaine treatment. These results reveal the physiological significance of TBSA in controlling lateral membrane partitioning in mycobacteria.</P>

2023

American Society for Microbiology

2150-7511

14

2

pp.e03396-22

10.1128/mbio.03396-22

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART124397316

fatty acids; lipidomics; membrane domain; phospholipids; transposon sequencing