Cellular compartmentation follows rules: The Schnepf theorem, its consequences and exceptions

Abstract

Is the spatial organization of membranes and compartments within cells subjected to any rules? Cellular compartmentation differs between prokaryotic and eukaryotic life, because it is present to a high degree only in eukaryotes. In 1964, Prof. Eberhard Schnepf formulated the compartmentation rule (Schnepf theorem), which posits that a biological membrane, the main physical structure responsible for cellular compartmentation, usually separates a plasmatic form a non-plasmatic phase. Here we review and re-investigate the Schnepf theorem by applying the theorem to different cellular structures, from bacterial cells to eukaryotes with their organelles and compartments. In conclusion, we can confirm the general correctness of the Schnepf theorem, noting explicit exceptions only in special cases such as endosymbiosis and parasitism.

Cell‐Inspired All‐Aqueous Microfluidics: From Intracellular Liquid–Liquid Phase Separation toward Advanced Biomaterials

“…While synthetic biology and artificially cellular systems are being developed, the current mimicry is mainly stayed at an infant stage and far from completion . It is important to note that the interior of cells at subcellular level is also very essential and is a treasury with inspirations for further investigation . Specifically, the biological intracellular environment is heterogeneous and full of distinct compartments with different compositions and properties .…”

“…[33][34][35][36] It is important to note that the interior of cells at subcellular level is also very essential and is a treasury with inspirations for further investigation. [37][38][39][40] Specifically, the biological intracellular environment is heterogeneous and full of distinct compartments with different compositions and properties. [40,41] For example, membrane-bound organelles such as the nucleus and mitochondria are surrounded by proteolipid membranes, while membraneless organelles are dynamic and stoichiometric stable complexes, mainly identified as RNA/protein coacervates in nucleolus.…”

Explaining the Origin of Three‐Membrane‐Bound Plastids in Dinoflagellates and Euglenophytes: Kleptoplastidy via Myzocytosis?

“…This is a reply to a comment published in BioEssays in the category “Thoughts and Opinions” by Andrzej Bodył on our paper “Cellular compartmentation follows rules: The Schnepf theorem, its consequences and exceptions.” In this article we introduced the “compartmentation rule” or Schnepf theorem, originally formulated by Eberhard Schnepf, to the international scientific community. We critically review the theorem and clearly state that as for every good rule there are exceptions to the Schnepf theorem as well, especially in case of endosymbiotically derived cellular structures, such as the three membrane‐bound complex plastids of dinoflagellates and euglenophytes, respectively, as well as in case of parasitism . We discuss myzocytosis –a feeding mechanism involving the sucking out of a prey cell's content usually followed by its digestion– as one potential process having led to the origin of the red or green algal‐derived plastids of dinoflagellates and euglenophytes, respectively, but we do not consider it as a likely evolutionary scenario.…”

“…Daniel Moog and Uwe G. Maier* This is a reply to a comment published in BioEssays in the category "Thoughts and Opinions" by Andrzej Bodył [1] on our paper "Cellular compartmentation follows rules: The Schnepf theorem, its consequences and exceptions." [2] In this article we introduced the "compartmentation rule" or Schnepf theorem, originally formulated by Eberhard Schnepf, to the international scientific community. We critically review the theorem and clearly state that as for every good rule there are exceptions to the Schnepf theorem as well, especially in case of endosymbiotically derived cellular structures, such as the three membrane-bound complex plastids of dinoflagellates and euglenophytes, respectively, as well as in case of parasitism.…”

“…We critically review the theorem and clearly state that as for every good rule there are exceptions to the Schnepf theorem as well, especially in case of endosymbiotically derived cellular structures, such as the three membrane-bound complex plastids of dinoflagellates and euglenophytes, respectively, as well as in case of parasitism. [2] We discuss myzocytosisa feeding mechanism involving the sucking out of a prey cell's content usually followed by its digestion-as one potential process having led to the origin of the red or green algal-derived plastids of dinoflagellates and euglenophytes, respectively, but we do not consider it as a likely evolutionary scenario. One of the major reasons for this is the fact that for kleptoplasty (the temporary stealing of plastids) following myzocytosis (or any form of specialized phagocytosis, see [3] ), the host gaining the plastid has to be equipped with exactly the right set of nucleusencoded genes to maintain the stolen organelle on evolutionary time scales.…”