INVESTIGADORES
RAIMUNDA daniel Cesar
artículos
Título:
Role in metal homeostasis of CtpD, a Co2+ transporting P1B4-ATPase of Mycobacterium smegmatis
Autor/es:
RAIMUNDA, DANIEL; LONG, JARUKIT; SASSETTI, C.M; ARGÜELLO, JOSE M
Revista:
MOLECULAR MICROBIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2012 p. 1139 - 1149
ISSN:
0950-382X
Resumen:
Genetic
studies in the tuberculosis mouse model have suggested that mycobacterial metal
efflux systems, such as the P1B4-ATPase CtpD, are important for pathogenesis. The
specificity for substrate metals largely determines the function of these
ATPases; however, various substrates have been reported for bacterial and plant
P1B4-ATPases leaving their function uncertain. Here we describe the functional
role of the CtpD protein of Mycobacterium smegmatis. An M. smegmatis mutant
strain lacking the ctpD gene was hypersensitive to Co2+ and Ni2+ and
accumulated these metals in the cytoplasm. ctpD transcription was induced by
both Co2+ and superoxide stress. Biochemical characterization of heterologously expressed,
affinity-purified CtpD showed that thisATPase is activated by Co2+, Ni2+ and to
a lesser extend Zn2+ (20% of maximum activity). The protein was also able to
bind one Co2+, Ni2+ or Zn2+ to its transmembrane transport site. These
observations indicate that CtpD is important for Co2+ and Ni2+ homeostasis in
M. smegmatis, and that M. tuberculosis CtpD orthologue could be involved in
metal detoxification and resisting cellular oxidative stress by modulating the
intracellular concentration of these metals.