Unraveling the Golgi Ribbon

Abstract

The Golgi apparatus lies at the heart of the secretory pathway where it receives, modifies, and sorts protein cargo to the proper intracellular or extracellular location. Although this secretory function is highly conserved throughout the eukaryotic kingdom, the structure of the Golgi complex is arranged very differently among species. In particular, Golgi membranes in vertebrate cells are integrated into a single compact entity termed the Golgi ribbon that is normally localized in the perinuclear area and in close vicinity to the centrosomes. This organization poses a challenge for cell division when the single Golgi ribbon needs to be partitioned into the two daughter cells. To ensure faithful inheritance in the progeny, the Golgi ribbon is divided in three consecutive steps in mitosis, namely disassembly, partitioning, and reassembly. However, the structure of the Golgi ribbon is only present in higher animals and Golgi disassembly during mitosis is not ubiquitous in all organisms. Therefore, there must be unique reasons to build up the Golgi in this particular conformation and to preserve it over generations. In this review, we first highlight the diversity of the Golgi architecture in different organisms and revisit the concept of the Golgi ribbon. Following on, we discuss why the ribbon is needed and how it forms in vertebrate cells. Lastly, we conclude with likely purposes of mitotic ribbon disassembly and further propose mechanisms by which it regulates mitosis.

The Golgi apparatus: insights from filamentous fungi

“…Cisternae have varying biochemical characteristics that correlate with their relative position in the stack. A typical mammalian interphase cell includes 40-100 stacks connected by membrane tubules to form a perinuclear Golgi ribbon, while in invertebrates stacks do not form a ribbon but instead are dispersed in the cytoplasm (Wei and Seemann 2010). In Drosophila melanogaster dendrites, cis-, medial-and trans-Golgi cisternae appear to be disconnected (not forming stacks) in vivo (Zhou et al 2014).…”

Positive feedback between golgi membranes, microtubules and ER-exit sites directs golgi de novo biogenesis

“…Although its structure has varied significantly during evolution, its basic molecular composition has been very well conserved, together with its fundamental role in the secretory pathway. In most eukaryotic organisms, the Golgi complex is composed of stacked flattened cisternae, and in mammalian cells it has an additional complexity level due to the lateral linking of its stacked units in the perinuclear area to form a ribbon (Wei and Seemann, 2010). Despite its complex organization, the Golgi complex is a very dynamic organelle (Lippincott-Schwartz and Zaal, 2000), and it undergoes dramatic structural changes during mitosis (Wei and Seemann, 2009).…”

Growth of the Mammalian Golgi Apparatus during Interphase

“…During interphase, the mammalian Golgi apparatus is organized as a single, elaborate structure of interconnected stacks termed the Golgi ribbon (1). As the cell progresses through the cell cycle, the Golgi apparatus, like other organelles, is thought to double in size or number prior to equal partitioning between daughter cells (2).…”