Identification of a protein phosphatase 2A family member that regulates cell cycle progression in Trypanosoma brucei.
The cell cycle consists of an orderly sequence of events, whose purpose is to faithfully replicate and segregate cellular components. Many events in the cell cycle are triggered by protein kinases and counteracting phosphoprotein phosphatases (PPP). In Trypanosoma brucei, RNAi has been used to characterize numerous regulatory kinases, while the role of protein phosphatases has primarily been deduced with inhibitors such as okadaic acid and calyculin. In the present study, we identify for the first time a protein phosphatase 2A family member (TbPP2A-1) whose knockdown with RNAi phenocopies the effects of okadaic acid (OKA). In bloodstream forms (BF) and insect stage procyclic forms (PF) RNAi of TbPP2A-1 generates a cell population characterized by: an inhibition of cell growth, a block in cytokinesis; continued synthesis of nuclear DNA leading to aneuploidy; continued mitosis leading to cells with N>2, and an unusual phenotype where number of kinetoplasts (and flagella) is less than the number of nuclei. An engineered cell line was constructed to further study TbPP2A-1 and to facilitate the discovery of other cell cycle regulatory genes.
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States.
Karen G
KG
Rothberg
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States.
Neal
N
Jetton
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States.
James G
JG
Hubbard
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States.
Daniel A
DA
Powell
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States.
Vidya
V
Pandarinath
Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, United States. Electronic address: lruben@mail.smu.edu.
Larry
L
Ruben
D002453:Cell Cycle; D055785:Gene Knockdown Techniques; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*
D054648:Protein Phosphatase 2
Basal bodies; Cell cycle regulation; Okadaic acid; PP2A; Phosphoprotein phosphatase; Trypanosoma brucei