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  • An amino‐terminal threonine/serine motif is necessary for activity of the Crp/Fnr homolog, MrpC and for Myxococcus xanthus developmental robustness
Title: An amino‐terminal threonine/serine motif is necessary for activity of the Crp/Fnr homolog, MrpC and for Myxococcus xanthus developmental robustness
Summary The Crp/Fnr family of transcriptional regulators play central roles in transcriptional control of diverse physiological responses, and are activated by a surprising diversity of mechanisms. MrpC is a Crp/Fnr homolog that controls theMyxococcus xanthusdevelopmental program. A long‐standing model proposed that MrpC activity is controlled by the Pkn8/Pkn14 serine/threonine kinase cascade, which phosphorylates MrpC on threonine residue(s) located in its extreme amino‐terminus. In this study, we demonstrate that a stretch of consecutive threonine and serine residues, T21T22S23S24,is necessary for MrpC activity by promoting efficient DNA binding. Mass spectrometry analysis indicated the TTSS motif is not directly phosphorylated by Pkn14in vitrobut is necessary for efficient Pkn14‐dependent phosphorylation on several residues in the remainder of the protein. In an important correction to a long‐standing model, we show Pkn8 and Pkn14 kinase activities do not play obvious roles in controlling MrpC activity in wild‐typeM. xanthusunder laboratory conditions. Instead, we propose Pkn14 modulates MrpC DNA binding in response to unknown environmental conditions. Interestingly, substitutions in the TTSS motif caused developmental defects that varied between biological replicates, revealing that MrpC plays a role in promoting a robust developmental phenotype.  more » « less
Award ID(s):
1651921
PAR ID:
10368661
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Molecular Microbiology
Volume:
112
Issue:
5
ISSN:
0950-382X
Format(s):
Medium: X Size: p. 1531-1551
Size(s):
p. 1531-1551
Sponsoring Org:
National Science Foundation
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