Isoform-specific Interaction of Golgin-160 with the Golgi-associated Protein PIST

Carolyn E. Machamer,Stuart W. Hicks

doi:10.1074/jbc.m504937200

Carolyn E. Machamer, Stuart W. Hicks

Open Access

https://doi.org/10.1074/jbc.m504937200

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Abstract

Golgin-160 belongs to the golgin family of Golgi-localized proteins, which have been implicated in Golgi structure and function. Golgin-160 possesses an N-terminal non-coiled-coil "head" domain followed by an extensive coiled-coil region. Using the N-terminal head domain of golgin-160 as bait in a yeast two-hybrid screen, the postsynaptic density-95/Discs large/zona occludens-1 (PDZ) domain protein interacting specifically with TC10 (PIST) was identified to interact with golgin-160. PIST (also known as GOPC, CAL, and FIG) has been implicated in the trafficking of a subset of plasma membrane proteins, supporting a role of golgin-160 in vesicular trafficking. Golgin-160 and PIST colocalize to Golgi membranes and interact in vivo. Glutathione S-transferase binding experiments identified an internal region of PIST that includes a coiled-coil domain, which interacts directly with golgin-160. Similar binding experiments identified a leucine-rich repeat within golgin-160 necessary for interaction with PIST. Therefore, our data suggest that golgin-160 may participate in PIST-dependent trafficking of cargo. Interestingly, we also discovered a widely expressed isoform of golgin-160, golgin-160B, which lacks the exon encoding the leucine repeat that mediates binding to PIST. As predicted, golgin-160B was unable to bind PIST. Full-length golgin-160 and golgin-160B may link distinct subsets of proteins to effect specific membrane trafficking pathways.

Highlights

The mammalian Golgi complex is composed of polarized stacks of cisternal membranes connected by tubules to form a reticular network of membranes located in a juxtanuclear position [1]
We previously showed that the N-terminal noncoiled-coil domain head domain of golgin-160 possesses Golgi targeting information [17]
The head domain of golgin-160 is cleaved by caspases during apoptosis, and this cleavage is required for apoptotic progression induced by specific stimuli and efficient disassembly of the Golgi complex [18, 19]

Summary

Introduction

The mammalian Golgi complex is composed of polarized stacks of cisternal membranes connected by tubules to form a reticular network of membranes located in a juxtanuclear position [1]. We discovered a widely expressed isoform of golgin-160, golgin-160B, which lacks the exon encoding the leucine repeat that mediates binding to PIST. We identify and characterize the binding of golgin-160 with PDZ domain protein interacting with TC10 (PIST).

Results

Conclusion