Parkinson?s associated P5-ATPases. Insights on the regulatory properties of SPF1 segment ctPi .

ADAMO HUGO P.; GRENÓN, PAULA; CORRADI, GERARDO

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Biofísica; 2019

The biochemical properties of the group P5 on transport ATPases are much lesscharacterized than those of other members of the family. In humans mutations in the P5-ATPases are associated with early onset Parkinson, Neuronal Ceroid Lipofuscinosis andHereditary Spastic Paraplegia. The primary sequence of P5-ATPases suggests that, similarto other P-ATPases, the molecular architecture of the P5-ATPases consist of an Action (A),Phosphorylation (P), Nucleotide binding (N) and transmembrane (M) domains. P5-ATPases however, have a unique stretch of 60-120 amino acids at the c-terminal end of theP domain (so-called segment ctP) with no homology in other P-ATPases. Previous studiesfrom our group have shown that the Spf1 from Saccharomyces cerevisiae is an activeATPase and forms the catalytic phosphoenzyme that characterizes the P-ATPases. Withthe aim of advancing the knowledge of the importance of the ctP segment we have usedsite-directed mutagenesis to obtain mutant (ΔctP)Spf1 in which the ctP segment is deleted.(ΔctP)Spf1 exhibited wild type levels of expression, ATP hydrolysis and phosphoenzymeformation. Moreover, (ΔctP)Spf1 was capable to rescue the caffeine sensitivity phenotypeof KO Spf1 cells as well as the wild type Spf1. The results indicate that the Spf1 P5-ATPasecan perform its basic functions without the need of the ΔctP segment.