An FHA phosphoprotein recognition domain mediates protein EmbR phosphorylation by PknH, a Ser/Thr protein kinase from Mycobacterium tuberculosis.
In bacteria, regulatory phosphorylation of proteins at serine and/or threonine residues by Ser/Thr protein kinase (STPK) is an emerging theme in prokaryotic signaling, particularly since the prediction of the occurrence of several STPKs from genome sequencing and sequence surveys. Here we show that protein PknH possesses an autokinase activity and belongs to the large STPK family found in Mycobacterium tuberculosis. Evidence is presented that PknH can also phosphorylate EmbR, a protein suspected to modulate the level of arabinosyltransferase activity involved in arabinan biosynthesis of arabinogalactan, a key molecule of the mycobacterial cell wall. Interestingly, EmbR possesses an FHA (forkhead-associated) domain, a newly described phosphoprotein recognition domain, which plays an essential role in PknH-EmbR interaction and phosphorylation of EmbR by PknH. It is demonstrated that mutation of each of three particular residues of this FHA domain, Arg312, Ser326, and Asn348, totally abolishes the PknH-mediated phosphorylation of EmbR, thus highlighting the critical role of this domain in the direct interaction between EmbR and PknH.
Molle
Virginie
V
Institut de Biologie et Chimie des Protéines, Université de Lyon, Centre National de la Recherche Scientifique, Lyon, France.
Kremer
Laurent
L
Girard-Blanc
Christine
C
Besra
Gurdyal S
GS
Cozzone
Alain J
AJ
Prost
Jean-François
JF
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002384:Catalysis; D003600:Cytosol / Q000737:chemistry / Q000378:metabolism; D004789:Enzyme Activation; D051858:Forkhead Transcription Factors; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D010430:Pentosyltransferases / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000502:physiology; D012694:Serine / Q000378:metabolism; D013379:Substrate Specificity; D013912:Threonine / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*
D001426:Bacterial Proteins; D051858:Forkhead Transcription Factors; D009687:Nuclear Proteins; D010750:Phosphoproteins; D014157:Transcription Factors; D013912:Threonine; D012694:Serine; D010430:Pentosyltransferases; C101967:arabinosyltransferase; C484411:PknH protein, Mycobacterium tuberculosis; D017346:Protein Serine-Threonine Kinases