RESUMO
Historically Black colleges and universities (HBCUs) offer high-quality education and produce leaders from various backgrounds, mainly being African American. Predominately White institutions can utilize practices that make HBCUs successful to mentor and graduate students of all backgrounds. We also suggest ways to bolster HBCUs so they can train more students.
Assuntos
Negro ou Afro-Americano , Estudantes , Logro , Humanos , UniversidadesRESUMO
It is becoming clear that in addition to gap junctions playing a role in cellâ»cell communication, gap junction proteins (connexins) located in cytoplasmic compartments may have other important functions. Mitochondrial connexin 43 (Cx43) is increased after ischemic preconditioning and has been suggested to play a protective role in the heart. How Cx43 traffics to the mitochondria and the interactions of mitochondria with other Cx43-containing structures are unclear. In this study, immunocytochemical, super-resolution, and transmission electron microscopy were used to detect cytoplasmic Cx43-containing structures and to demonstrate their interactions with other cytoplasmic organelles. The most prominent cytoplasmic Cx43-containing structures-annular gap junctions-were demonstrated to form intimate associations with lysosomes as well as with mitochondria. Surprisingly, the frequency of associations between mitochondria and annular gap junctions was greater than that between lysosomes and annular gap junctions. The benefits of annular gap junction/mitochondrial associations are not known. However, it is tempting to suggest, among other possibilities, that the contact between annular gap junction vesicles and mitochondria facilitates Cx43 delivery to the mitochondria. Furthermore, it points to the need for investigating annular gap junctions as more than only vesicles destined for degradation.
Assuntos
Vesículas Citoplasmáticas/metabolismo , Junções Comunicantes/metabolismo , Proteínas de Fluorescência Verde/metabolismo , Mitocôndrias/metabolismo , Imagem Óptica , Comunicação Celular , Linhagem Celular Tumoral , Conexina 43/química , Conexina 43/genética , Conexina 43/metabolismo , Vesículas Citoplasmáticas/química , Junções Comunicantes/química , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Humanos , Imuno-Histoquímica , Citometria de Varredura a Laser , Lisossomos/química , Lisossomos/metabolismo , Mitocôndrias/químicaRESUMO
Both connexins and signal transduction pathways have been independently shown to play critical roles in lens homeostasis, but little is known about potential cooperation between these two intercellular communication systems. To investigate whether growth factor signaling and gap junctional communication interact during the development of lens homeostasis, we examined the effect of mitogen-activated protein kinase (MAPK) signaling on coupling mediated by specific lens connexins by using a combination of in vitro and in vivo assays. Activation of MAPK signaling pathways significantly increased coupling provided by Cx50, but not Cx46, in paired Xenopus laevis oocytes in vitro, as well as between freshly isolated lens cells in vivo. Constitutively active MAPK signaling caused macrophthalmia, cataract, glucose accumulation, vacuole formation in differentiating fibers, and lens rupture in vivo. The specific removal or replacement of Cx50, but not Cx46, ameliorated all five pathological conditions in transgenic mice. These results indicate that MAPK signaling specifically modulates coupling mediated by Cx50 and that gap junctional communication and signal transduction pathways may interact in osmotic regulation during postnatal fiber development.