Molecular cloning and characterization of mitogen-activated protein kinase 2 in Toxoplasma gondii.
Mitogen-activated protein kinase (MAPK) pathways are major signal transduction systems by which eukaryotic cells convert environmental cues to intracellular events, such as cell proliferation and differentiation. Toxoplasma gondii is an obligate intracellular protozoan that is both a human and animal pathogen. This Apicomplexan causes significant morbidity and mortality in immune-competent and immune-compromised hosts. In humans, the most common manifestations of T. gondii infections are chorioretinitis in congenital infection and encephalitis in immune-compromised patients, such as patients with advanced AIDS. We have identified a T. gondii homolog of the MAPK family that we have called TgMAPK2. Sequence analyses demonstrated that TgMAPK2 has homology with lower eukaryotic ERK2 but has significant differences from mammalian ERK2. TgMAPK2 has an open reading frame of 2,037 bp, 678 amino acids, and its molecular weight is 73.1 kDa. It contains the typical 12 subdomains of a MAPK and has a TDY motif in the dual phosphorylation and activation subdomains. This suggests that TgMAPK2 may play an important role in stress response. recombinant TgMAPK2 was catalytically active and was not inhibited by a human ERK2 inhibitor, FR180204. A partial TgMAPK2 lacking the ATP-binding motifs GxGxxGxV was successfully regulated by a ligand-controlled destabilization domain (ddFKBP) expression vector system in T. gondii. Since TgMAPK2 is significantly different from its mammalian counterpart, it may be useful as a drug target. This work establishes a foundation for further study for this unique kinase.
Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA.
Huan
H
Huang
Yan Fen
YF
Ma
Yi
Y
Bao
Hattie
H
Lee
Michael P
MP
Lisanti
Herbert B
HB
Tanowitz
Louis M
LM
Weiss
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D040461:Gene Components; D006801:Humans; D015151:Immunoblotting; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D011720:Pyrazoles; D011724:Pyridazines; D012394:Rosaniline Dyes; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D014122:Toxoplasma / Q000201:enzymology*
D017931:DNA Primers; C505241:FR 180204; D011720:Pyrazoles; D011724:Pyridazines; D012394:Rosaniline Dyes; C048139:Coomassie blue; D019950:Mitogen-Activated Protein Kinase 1