Molecular cloning and characterisation of SmSLK, a novel Ste20-like kinase in Schistosoma mansoni.
Serine/threonine kinases of the Ste20 group play important roles in various cellular functions such as growth, apoptosis and morphogenesis. This family includes p21-Activated Kinases (PAKs) and Germinal Center Kinases (GCKs) families which contain their kinase domain in the C-terminal and N-terminal position, respectively. Here, we report the characterisation of a novel Ste20-like kinase (SLK) in the helminth parasite Schistosoma mansoni (SmSLK). SmSLK belongs to the GCK subfamily and contains a conserved N-terminal Ste20-like catalytic domain and C-terminal coiled-coil structures homologous to mammalian Lymphocyte Oriented Kinase (LOK) and SLK kinases and described as regulatory domains in these proteins. Gene assembly was performed using S. mansoni sequences available from genomic databases and indicated that SmSLK is composed of 18 exons and present in one copy in the S. mansoni genome. RT-PCR experiments demonstrated an alternative splicing of SmSLK in the exon 9 encoding the hinge region between kinase and coiled-coil domains of SmSLK and showed the expression of both transcript isoforms (SmSLK and SmSLK-S in which exon 9 is deleted) in all the S. mansoni parasite stages. Most of the Ste20-related proteins are active kinases known to regulate mitogen-activated protein kinase (MAPK) cascades. We demonstrated the kinase activity of SmSLK and SmSLK-S and their capacity to activate the MAPK/Jun N-terminal kinase (JNK) pathway in human embryonic kidney (HEK) cells as well as in Xenopus oocytes. Immunofluorescence studies indicated that SmSLK proteins were abundant in the tegument of adult schistosomes. Therefore, these results indicate that SmSLK is a new member of the GCK protein family that could participate in the regulation of MAPK cascade activation during host-parasite interactions.
Yan
Yutao
Y
Inserm, U 547, Lille, France.
Tulasne
David
D
Browaeys
Edith
E
Cailliau
Katia
K
Khayath
Naji
N
Pierce
Raymond J
RJ
Trolet
Jacques
J
Fafeur
Veronique
V
Ben Younes
Amena
A
Dissous
Colette
C
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004789:Enzyme Activation; D000081410:Germinal Center Kinases; D006801:Humans; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism; D008969:Molecular Sequence Data; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012550:Schistosoma mansoni / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014162:Transfection; D014982:Xenopus laevis
D000081410:Germinal Center Kinases; D017346:Protein Serine-Threonine Kinases; D048055:Mitogen-Activated Protein Kinase 8