Mechanisms of the Copper-dependent Turnover of the Copper Chaperone for Superoxide Dismutase

Human superoxide dismutase 1 (hSOD1) maturation through interaction with human copper chaperone for SOD1 (hCCS)

“…for SOD1 maturation, the necessity for and role of D1 remained inconclusive (30,32,33,41,48). The previous reported findings were principally based on assays measuring for overall SOD1 activity (which requires complete SOD1 maturation); thus, they were unable to monitor separately for copper acquisition and disulfide bond formation, as accomplished in this work using NMR.…”

“…In a previous study examining the roles of the individual domains of hCCS at the cellular level, neither SOD1 activity nor copper incorporation into SOD1 was observed in hCCS −/− mammalian cells transfected with hCCSD2,3 or with a full-length hCCS mutant with Cys-to-Ser mutations in the D1 MXCXXC motif (32).…”

“…The human CCS N-terminal domain 1 (D1) is homologous and shows the same fold of the Atx1-like metallochaperones and harbors the MXCXXC copper-binding motif typical of this family of proteins. Human D1 is essential for hSOD1 copper acquisition in vivo (32), whereas yeast D1 appears to be necessary only under copper-limiting conditions (33). CCS domain 2 (D2) is structurally similar to SOD1 and has been postulated to be critical for CCS-SOD1 protein recognition (33)(34)(35).…”

Palmitoylation of Superoxide Dismutase 1 (SOD1) Is Increased for Familial Amyotrophic Lateral Sclerosis-linked SOD1 Mutants

“…We also observed that palmitoylation occurs predominantly on disulfide-reduced as opposed to disulfide-bonded SOD1. Increased CCS expression, which increases SOD1 disulfide bonding and other maturation steps (28,29), caused a decrease in wtSOD1 palmitoylation, with a less significant decrease in A4V and no significant change in G93A mtSOD1 palmitoylation. These findings suggest that SOD1 palmitoylation occurs prior to the intramolecular disulfide-bonding step in SOD1 maturation and that palmitoylation is increased under conditions when there is more immature disulfide-reduced SOD1.…”

“…Because CCS increases SOD1 intramolecular disulfide bonding and maturation (28,29,36), we wanted to test how increasing CCS levels affect SOD1 palmitoylation. As expected, we observed an increase in the relative levels of disulfide-bonded to disulfide-reduced SOD1-YFP when CCS levels were increased (Fig.…”