6 research outputs found
Recommended from our members
Student Interviews: 1967
A series of fifteen- to thirty-minute interviews was conducted with eight members of the first graduating class of the University of California, Santa Cruz, and with four sophomores who were members of the first four-year class to graduate from the Santa Cruz campus. The students spoke quite candidly about the strengths and weaknesses of the University, administration, faculty, classes, and general campus life, and commented on the changes that they thought should or would occur as the campus grows larger
Recommended from our members
Student Interviews: 1967
A series of fifteen- to thirty-minute interviews was conducted with eight members of the first graduating class of the University of California, Santa Cruz, and with four sophomores who were members of the first four-year class to graduate from the Santa Cruz campus. The students spoke quite candidly about the strengths and weaknesses of the University, administration, faculty, classes, and general campus life, and commented on the changes that they thought should or would occur as the campus grows larger
Mitochondrial organization and Ca2+ uptake
Mitochondria may function as multiple separate organelles or as a single electrically coupled continuum to modulate changes in [Ca2+]c (cytoplasmic Ca2+ concentration) in various cell types. Mitochondria may also be tethered to the internal Ca2+ store or plasma membrane in particular parts of cells to facilitate the organelles modulation of local and global [Ca2+]c increases. Differences in the organization and positioning contributes significantly to the at times apparently contradictory reports on the way mitochondria modulate [Ca2+]c signals. In the present paper, we review the organization of mitochondria and the organelles role in Ca2+ signalling
Mitochondrial regulation of cytosolic Ca2+ signals in smooth muscle
The cytosolic Ca2+ concentration ([Ca2+]c) controls virtually every activity of smooth muscle, including contraction, migration, transcription, division and apoptosis. These processes may be activated by large (>10 μM) amplitude [Ca2+]c increases, which occur in small restricted regions of the cell or by smaller (<1 μM) amplitude changes throughout the bulk cytoplasm. Mitochondria contribute to the regulation of these signals by taking up Ca2+. However, mitochondria’s reported low affinity for Ca2+ is thought to require the organelle to be positioned close to ion channels and within a microdomain of high [Ca2+]. In cultured smooth muscle, mitochondria are highly dynamic structures but in native smooth muscle mitochondria are immobile, apparently strategically positioned organelles that regulate the upstroke and amplitude of IP3-evoked Ca2+ signals and IP3 receptor (IP3R) cluster activity. These observations suggest mitochondria are positioned within the high [Ca2+] microdomain arising from an IP3R cluster to exert significant local control of channel activity. On the other hand, neither the upstroke nor amplitude of voltage-dependent Ca2+ entry is modulated by mitochondria; rather, it is the declining phase of the transient that is regulated by the organelle. Control of the declining phase of the transient requires a high mitochondrial affinity for Ca2+ to enable uptake to occur over the normal physiological Ca2+ range (<1 μM). Thus, in smooth muscle, mitochondria regulate Ca2+ signals exerting effects over a large range of [Ca2+] (∼200 nM to at least tens of micromolar) to provide a wide dynamic range in the control of Ca2+ signals