Cell expression of a four extra octarepeat mutated PrPC modifies cell structure and cell cycle regulation.
RK13 cell lines generated to express bovine PrP(C) with a four extra octarepeat insertional mutation (Bo-10ORPrP(C)) show partially insoluble PrP(C) and lower rates of cell growth when compared to either the same cells expressing wild type Bo-6ORPrP(C) or the original RK13 cell line. The expression of Bo-10ORPrP(C) in cell cultures was also associated with changes in cell size and reorganization of the actin cytoskeleton. This last process was reversed by Clostridium difficile toxin-B, a specific inhibitor of small GTPase proteins. Further, in clones expressing Bo-10ORPrP(C), increased proportions of cells at cell cycle stage G2/M were observed. Proteasome inhibitors caused a further expansion of G2/M-stage cells that was more marked in cell lines expressing Bo-10ORPrP(C) than those expressing Bo-6ORPrP(C), while this effect was minimal or null in the original RK13 cell line. Hence, the presence of Bo-10ORPrP(C) in RK13 cells promotes cell cycle arrest at G2/M, and the effect is amplified by proteasome inhibition. These findings suggest a role for PrP(C) in cell morphology and cell cycle regulation, and open new avenues for understanding the mechanisms underlying PrP mutation-associated diseases.
Martín
Sergio F
SF
Centro de Investigación en Sanidad (CISA-INIA), Ctra. de Algete a El Casar, km. 8.100, 28130 Valdeolmos, Madrid, Spain.
Herva
María E
ME
Espinosa
Juan-Carlos
JC
Parra
Beatriz
B
Castilla
Joaquín
J
Brun
Alejandro
A
Torres
Juan M
JM
D000818:Animals; D001427:Bacterial Toxins / Q000494:pharmacology; D002417:Cattle; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D004789:Enzyme Activation; D016195:G2 Phase / Q000187:drug effects / Q000235:genetics; D020559:Monomeric GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D009154:Mutation; D018621:PrPC Proteins / Q000235:genetics / Q000378:metabolism*; D017096:Prion Diseases / Q000235:genetics; D011480:Protease Inhibitors / Q000494:pharmacology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D061988:Proteasome Inhibitors; D011817:Rabbits
D001427:Bacterial Toxins; C488583:Clostridium difficile lethal toxin B; D018621:PrPC Proteins; D011480:Protease Inhibitors; D061988:Proteasome Inhibitors; D046988:Proteasome Endopeptidase Complex; D020559:Monomeric GTP-Binding Proteins