The time-honored paradigm for mammary gland transepithelial calcium transport into milk is centered on the view that most, if not all, calcium enters milk through the secretory pathway, and no ionic calcium directly crosses the apical plasma membrane. Data from several recent studies all strongly suggest that most calcium, in fact, is extruded across the apical plasma membrane directly by the plasma membrane calcium-ATPase isoform 2 (PMCA2). In this review we break down transcellular calcium transport into the tasks of calcium entry, calcium sequestration and compartmentalization, and calcium extrusion. We compare and contrast the steps of calcium transport into milk by mammary epithelial cells, and the specific molecules that might perform these tasks, with well-characterized calcium transport mechanisms in other epithelia, such as the kidney, small intestine, and salivary gland. Finally, we suggest an updated model for calcium transport into milk that incorporates calcium transport across the apical plasma membrane.
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http://dx.doi.org/10.1007/s10911-007-9057-1 | DOI Listing |
Nat Commun
December 2024
Nanobiology Institute, Yale University, West Haven, CT, USA.
Neurotransmitters are released from synaptic vesicles with remarkable precision in response to presynaptic calcium influx but exhibit significant heterogeneity in exocytosis timing and efficacy based on the recent history of activity. This heterogeneity is critical for information transfer in the brain, yet its molecular basis remains poorly understood. Here, we employ a biochemically-defined fusion assay under physiologically relevant conditions to delineate the minimal protein machinery sufficient to account for various modes of calcium-triggered vesicle fusion dynamics.
View Article and Find Full Text PDFArch Razi Inst
June 2024
Medical Plants Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran.
In the present study, the mechanisms involved in scopolamine-induced memory impairment have been investigated. The molecular events that take place during memory mostly include mechanisms that are seen in the acquisition phase. Results showed that one of the mechanisms of memory destruction caused by scopolamine, in addition to weakening the cholinergic system, is the indirect effect of scopolamine on other neurotransmitter systems, including the glutamatergic system.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
December 2024
Department of Biochemistry, Cell Biology and Microbiology, Mari State University, 424001 Yoshkar-Ola, Russia.
Objective: Ca overload of muscle fibers is one of the factors that secondarily aggravate the development of Duchenne muscular dystrophy (DMD). The purpose of this study is to evaluate the effects of the Ca channel modulator 2-aminoethoxydiphenyl borate (APB) on skeletal muscle pathology in dystrophin-deficient mice.
Methods: Mice were randomly divided into six groups: wild type (WT), WT+3 mg/kg APB, WT+10 mg/kg APB, , +3 mg/kg APB, +10 mg/kg APB.
Bioact Mater
April 2025
Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Human long bones exhibit pore size gradients with small pores in the exterior cortical bone and large pores in the interior cancellous bone. However, most current bone tissue engineering (BTE) scaffolds only have homogeneous porous structures that do not resemble the graded architectures of natural bones. Pore-size graded (PSG) scaffolds are attractive for BTE since they can provide biomimicking porous structures that may lead to enhanced bone tissue regeneration.
View Article and Find Full Text PDFCell Biosci
December 2024
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, USA.
Mammalian reproduction requires that nursing mothers transfer large amounts of calcium to their offspring through milk. Meeting this demand requires the activation of a brain-breast-bone circuit during lactation that coordinates changes in systemic hormones, dietary calcium intake, skeletal turnover, and calcium transport into milk. Classically, increased bone resorption via increased parathyroid hormone-related protein and low estrogen levels is the main source of calcium for milk production during lactation.
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