PICK1, an anchoring protein that specifically targets protein kinase Calpha to mitochondria selectively upon serum stimulation in NIH 3T3 cells.
PICK1 binds to protein kinase Calpha (PKCalpha) through the carboxylate-binding loop in its PDZ (PSD95/Disc-large/ZO-1) domain and the C terminus of PKCalpha. We have previously shown that PICK1 modulates the catalytic activity of PKC selectively toward the antiproliferative gene TIS21. To investigate whether PICK1 plays a role in targeting activated PKCalpha to a particular intracellular compartment in addition to regulating PKC activity, we examine the localization of PICK1 and PKCalpha in response to various stimuli. Double staining with organelle markers and anti-rPICK1 antibodies reveals that PICK1 is associated with mitochondria but not with endoplasmic reticulum or Golgi in NIH 3T3 cells. Deletion of the PDZ domain impairs the mitochondria localization of PICK1, whereas mutations in the carboxylate-binding loop do not have an effect, suggesting that PICK1 can bind PKCalpha and mitochondria simultaneously. Upon serum stimulation, PICK1 translocates and displays a dense ring-like structure around the nucleus, where it still associates with mitochondria. A substantial portion of PKCalpha is concomitantly found in the condense perinuclear region. The C terminal-deleted PKCalpha fails to translocate and remains a diffuse cytoplasmic distribution, indicating that a direct interaction between PICK1 and PKCalpha is required for PKCalpha anchoring to mitochondria. 12-O-Tetradecanoylphorbol-13-acetate stimulation, in contrast, causes translocation of PKCalpha to the plasma membrane, whereas the majority of PICK1 remains in a cytoplasmic punctate pattern. Deletion at the C terminus of PKCalpha has no effect on 12-O-tetradecanoylphorbol-13-acetate-induced translocation. These findings indicate a previously unidentified role for PICK1 in anchoring PKCalpha to mitochondria in a ligand-specific manner.
Wang
Wei-Li
WL
Department of Biochemistry, National Yang-Ming University, Taipei, 112, Taiwan.
Yeh
Sheau-Farn
SF
Chang
Yuan-I
YI
Hsiao
Shun-Fang
SF
Lian
Wei-Nan
WN
Lin
Chi-Hung
CH
Huang
Chi-Ying F
CY
Lin
Wey-Jinq
WJ
D016475:3T3 Cells; D000818:Animals; D002352:Carrier Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D018797:Cell Cycle Proteins; D005312:Fetal Blood / Q000502:physiology*; D051379:Mice; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D010455:Peptides / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D021381:Protein Transport; D000075370:Receptors for Activated C Kinase; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D010455:Peptides; C091822:Prkcabp protein, mouse; D000075370:Receptors for Activated C Kinase; C070301:peptide I; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D013755:Tetradecanoylphorbol Acetate