Golgi enzymes are retrieved from the plasma membrane to the trans-Golgi network

The Golgi complex is not only a central hub for bidirectional protein trafficking, but also a key site for post-translational modifications; the enzymes responsible are trafficked to the Golgi. To determine whether Golgi-resident enzymes can be recaptured from distal sites, we employed a nanobody-based transport assay. While most enzymes studied localized predominantly to the Golgi complex, some were also observed at the plasma membrane. Using sulfation-competent and fluorescently marked nanobody, we observed that certain enzymes are capable of retrograde transport to the trans-Golgi network. In contrast, classical and abundant recycling receptors readily internalized the nanobody but did not undergo retrograde transport. Our findings provide evidence that select Golgi enzymes can be retrieved from the cell surface to the sulfation compartment.