Cellular compartment

About: Cellular compartment is a research topic. Over the lifetime, 1082 publications have been published within this topic receiving 53794 citations. The topic is also known as: cell compartmentation.

Chip-calorimetric assessment of heat generation during Ca2+ uptake by digitonin-permeabilized Trypanosoma cruzi

Abstract: Ca2+ signaling in trypanosomatids is an important component of energy metabolism regulation and therefore, cytosolic Ca2+ concentration is finely regulated by Ca2+ transport through the plasma membrane and Ca2+ uptake and release by intracellular organelles. To maintain intracellular Ca2+ homeostasis with different gradients of the ion within the cellular compartments, there is an energy cost and also energy dissipation in the form of heat. Using an innovative segmented fusion technique of a chip-calorimeter and CRISPR/Cas9 knockout (–KO) Trypanosoma cruzi cell lines, we evaluated the heat generation during Ca2+ uptake by digitonin-permeabilized T. cruzi epimastigotes, a system consisting of Ca2+ uptake predominantly by mitochondria and acidocalcisomes. We used three T. cruzi epimastigotes cell lines: control cells denominated scrambled, cells with the absence of the pyruvate dehydrogenase phosphatase (TcPDP-KO) and cells lacking mitochondrial Ca2+ uptake via the mitochondrial calcium uniporter (TcMCU-KO), that presented, in this respective order, decreasing rates and capacities of Ca2+ uptake. TcPDP-KO cells exhibited the lowest heat production following Ca2+ addition, which may be due to its lower mitochondrial oxidative phosphorylation capacity and lower ATP availability for acidocalcisomal Ca2+ uptake. Scrambled and TcMCU-KO cells exhibited similar Ca2+-induced heat effects, which correlates with a higher ATP-dependent acidocalcisomal Ca2+ uptake in these cells. Our results show evidences that mitochondrial Ca2+ transport via the uniporter is minimally heat dissipative, while ATPase pumps in acidocalcisomes possess a predominant contribution to the heat generated during Ca2+ uptake.

Chapter 7 Mechanisms of intracellular pH regulation

Abstract: Publisher Summary The regulation of intracellular pH is of paramount importance in the maintenance of many cellular functions. Intracellular (cytosolic) pH is regulated at a level that is different from the extracellular pH. In addition, different compartments within the cell display pH values that differ by up to 3 units from the cytosolic pH. The prevalence of specific pH levels within the particular cellular compartments is not fortuitous. Precise control over intracellular pH, both cytosolic and intraorganellar, is critical to the proper functioning of the cell. Intracellular membrane traffic, endocytosis and receptor recycling, and cytosolic enzyme function are but a few of the myriad processes that are pH dependent. This chapter describes the recent advances in the understanding of some of the major mechanisms responsible for this precise regulation. In addition, a brief methodological section is also provided. Finally, the functional significance of cytosolic and organellar pH is discussed in some detail.

Calcium in plant peroxisomes. What for

Abstract: Peroxisome organelles have a versatile metabolism whose enzymatic content can be modulated by physiological and environment-dependent cellular conditions. They are characterized by a highly active nitro-oxidative metabolism and basic elements (H2O2 and nitric oxide (NO)) with signaling properties. However, new elements have increased our understanding of the connections between peroxisomes and other cellular compartments. Furthermore, the presence of calcium (Ca2+) intensifies communication between different signaling molecules and the relationship of Ca2+ itself with NO and H2O2.