GCP60 preferentially interacts with a caspase-generated golgin-160 fragment.
Golgin-160, a ubiquitous protein in vertebrates, localizes to the cytoplasmic face of the Golgi complex. Golgin-160 has a large coiled-coil C-terminal domain and a non-coiled-coil N-terminal ("head") domain. The head domain contains important motifs, including a nuclear localization signal, a Golgi targeting domain, and three aspartates that are recognized by caspases during apoptosis. Some of the caspase cleavage products accumulate in the nucleus when overexpressed. Expression of a non-cleavable form of golgin-160 impairs apoptosis induced by some pro-apoptotic stimuli; thus cleavage of golgin-160 appears to play a role in apoptotic signaling. We used a yeast two-hybrid assay to screen for interactors of the golgin-160 head and identified GCP60 (Golgi complex-associated protein of 60 kDa). Further analysis demonstrated that GCP60 interacts preferentially with one of the golgin-160 caspase cleavage fragments (residues 140-311). This strong interaction prevented the golgin-160 fragment from accumulating in the nucleus when this fragment and GCP60 were overexpressed. In addition, cells overexpressing GCP60 were more sensitive to apoptosis induced by staurosporine, suggesting that nuclear-localized golgin-160-(140-311) might promote cell survival. Our results suggest a potential mechanism for regulating the nuclear translocation and potential functions of golgin-160 fragments.
Sbodio
Juan I
JI
Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Hicks
Stuart W
SW
Simon
Dan
D
Machamer
Carolyn E
CE
D021581:Active Transport, Cell Nucleus; D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D017209:Apoptosis; D001324:Autoantigens / Q000737:chemistry / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000502:physiology; D002467:Cell Nucleus / Q000378:metabolism; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000502:physiology*; D010446:Peptide Fragments / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology; D020798:Two-Hybrid System Techniques
C449459:ACBD3 protein, human; D048868:Adaptor Proteins, Signal Transducing; D001324:Autoantigens; C108388:GOLGA3 protein, human; D000077614:Golgi Matrix Proteins; D008565:Membrane Proteins; D010446:Peptide Fragments; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D019311:Staurosporine