PMID- 20586425
OWN - NLM
STAT- MEDLINE
DCOM- 20100907
LR  - 20131121
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Linking)
VI  - 49
IP  - 31
DP  - 2010 Aug 10
TI  - Phosphomimetic substitution of cytochrome C tyrosine 48 decreases respiration and 
      binding to cardiolipin and abolishes ability to trigger downstream caspase 
      activation.
PG  - 6705-14
LID - 10.1021/bi100486s [doi]
AB  - Mammalian cytochrome c (Cytc) transfers electrons from the bc(1) complex to 
      cytochrome c oxidase (CcO) as part of the mitochondrial electron transport chain, 
      and it also participates in type II apoptosis. Our recent discovery of two 
      tyrosine phosphorylation sites in Cytc, Tyr97 in bovine heart and Tyr48 in bovine 
      liver, indicates that Cytc functions are regulated through cell signaling. To 
      characterize the role of Cytc tyrosine phosphorylation in detail using an 
      independent approach, we here overexpressed and purified a Tyr48Glu mutant Cytc, 
      mimicking the in vivo Tyr48 phosphorylation found in cow liver, along with 
      wild-type and Tyr48Phe variants as controls. The midpoint redox potential of the 
      phosphomimetic mutant was decreased by 45 mV compared to control (192 vs 237 mV). 
      Similar to Tyr48 in vivo phosphorylated Cytc, direct kinetic analysis of the Cytc 
      reaction with isolated CcO revealed decreased V(max) for the Tyr48Glu mutant by 
      30% compared to wild type or the Tyr48Phe variants. Moreover, the phosphomimetic 
      substitution resulted in major changes of Cytc functions related to apoptosis. 
      The binding affinity of Tyr48Glu Cytc to cardiolipin was decreased by about 30% 
      compared to wild type or the Tyr48Phe variants, and Cytc peroxidase activity of 
      the Tyr48Glu mutant was cardiolipin-inducible only at high cardiolipin 
      concentration, unlike controls. Importantly, the Tyr48Glu Cytc failed to induce 
      any detectable downstream activation of caspase-3. Our data suggest that in vivo 
      Tyr48 phosphorylation might serve as an antiapoptotic switch and highlight the 
      strategic position and role of the conserved Cytc residue Tyr48 in regulating 
      multiple functions of Cytc.
FAU - Pecina, Petr
AU  - Pecina P
AD  - Center for Molecular Medicine and Genetics, Wayne State University School of 
      Medicine, Detroit, Michigan 48201, USA.
FAU - Borisenko, Grigory G
AU  - Borisenko GG
FAU - Belikova, Natalia A
AU  - Belikova NA
FAU - Tyurina, Yulia Y
AU  - Tyurina YY
FAU - Pecinova, Alena
AU  - Pecinova A
FAU - Lee, Icksoo
AU  - Lee I
FAU - Samhan-Arias, Alejandro K
AU  - Samhan-Arias AK
FAU - Przyklenk, Karin
AU  - Przyklenk K
FAU - Kagan, Valerian E
AU  - Kagan VE
FAU - Huttemann, Maik
AU  - Huttemann M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Cardiolipins)
RN  - 0 (Organophosphates)
RN  - 42HK56048U (Tyrosine)
RN  - 9007-43-6 (Cytochromes c)
RN  - EC 3.4.22.- (Caspases)
SB  - IM
MH  - Animals
MH  - Apoptosis
MH  - Cardiolipins/metabolism
MH  - Caspases/metabolism
MH  - Cattle
MH  - Cell Respiration
MH  - Cytochromes c/chemistry/genetics/*metabolism
MH  - Mice
MH  - *Mutation
MH  - Organophosphates/*chemistry
MH  - Phosphorylation
MH  - Protein Binding
MH  - Rats
MH  - Tyrosine/*metabolism
EDAT- 2010/07/01 06:00
MHDA- 2010/09/08 06:00
CRDT- 2010/07/01 06:00
PHST- 2010/07/01 06:00 [entrez]
PHST- 2010/07/01 06:00 [pubmed]
PHST- 2010/09/08 06:00 [medline]
AID - 10.1021/bi100486s [doi]
PST - ppublish
SO  - Biochemistry. 2010 Aug 10;49(31):6705-14. doi: 10.1021/bi100486s.