  The Golgi apparatus has intrigued researchers since its discovery and despite
the advances, there are still many open questions in regards to its shape and
function. Here, we propose a mechanical model of Golgi apparatus stack and
explain its most elementary geometrical properties: the equilibrium number of
cisternae, the stack size, and its general equilibrium shape. In order to gain
comprehensive insight into the stack morphology, we combine both analytical and
numerical methods. We successfully reconstruct the stack morphology using
minimal assumptions, thus identifying the most dominant factors regulating the
stack shape. We demonstrate that energy-wise the stack prefers an overall bent
shape and show strong evidence that the adhesion strength determines the
equilibrium number of cisternae per stack. We explore the morphological role of
fenestrations and discuss their impact on the overall stack structure. We also
comment on the effects of the membrane asymmetry on the shape of the cisternae
and thus offer a broad steady-state study of the stack morphology and present a
method that can be used also for other membrane-bound organelles.
