Faculty Opinions recommendation of Induction of Na+/Pi cotransport system in the plasma membrane of Chara corallina requires external Na+ and low levels of Pi.

2002 ◽  
Author(s):  
Enrico Martinoia
Keyword(s):  
Plasma Membrane ◽  
Chara Corallina ◽  
Cotransport System ◽  
Low Levels

Differential binding of gold-labeled zona pellucida glycoproteins mZP2 and mZP3 to mouse sperm membrane compartments

Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 141-149 ◽  
Author(s):  
S. Mortillo ◽  
P.M. Wassarman
Keyword(s):  
Plasma Membrane ◽  
Zona Pellucida ◽  
Transmission Electron ◽  
Acrosomal Membrane ◽  
Membrane Compartments ◽  
Sperm Membrane ◽  
Differential Binding ◽  
Inner Acrosomal Membrane ◽  
Low Levels ◽  
Species Specific

Egg zona pellucida glycoproteins mZP3 and mZP2 serve as primary and secondary sperm receptors, respectively, during initial stages of fertilization in mice [Wassarman (1988) A. Rev. Biochem. 57, 415–442]. These receptors interact with complementary egg-binding proteins (EBPs) located on the sperm surface to support species-specific gamete adhesion. Results of whole-mount autoradiographic experiments suggest that purified egg mZP3 and mZP2 bind preferentially to acrosome-intact (AI) and acrosome-reacted (AR) sperm heads, respectively [Bleil and Wassarman (1986) J. Cell Biol. 102, 1363–1371]. Here, we used purified egg mZP2, egg mZP3 and fetuin, which were coupled directly to colloidal gold (‘gold-probes’), to examine binding of these glycoproteins to membrane compartments of AI and AR sperm by transmission electron microscopy. mZP3 gold-probes were found associated primarily with plasma membrane overlying the acrosomal and post-acrosomal regions of AI sperm heads. They were also found associated with plasma membrane overlying the post-acrosomal region of AR sperm heads. mZP2 gold-probes were found associated primarily with inner acrosomal membrane of AR sperm heads, although some gold was associated with outer acrosomal membrane of AI sperm that had holes in plasma membrane overlying the acrosome. Fetuin gold-probes, used to assess background levels of binding, were bound at relatively low levels to plasma membrane and inner acrosomal membrane of AI and AR sperm, respectively. None of the gold-probes exhibited significant binding to sperm tails, or to red blood cells and residual bodies present in sperm preparations. These results provide further evidence that mZP2 and mZP3 bind preferentially to heads of AR and AI sperm, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Control of phosphate transport across the plasma membrane of Chara corallina

1998 ◽  
Vol 49 (318) ◽  
pp. 13-19 ◽  
Author(s):  
T. Mimura ◽  
R. J. Reid ◽  
F. A. Smith
Keyword(s):  
Plasma Membrane ◽  
Phosphate Transport ◽  
Chara Corallina

Plasma membrane calcium pumps in smooth muscle: from fictional molecules to novel inhibitors

2005 ◽  
Vol 83 (8-9) ◽  
pp. 743-754 ◽  
Author(s):  
Jyoti Pande ◽  
Ashok K Grover
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Calcium Pumps ◽  
Cell Functions ◽  
Kinase C ◽  
Animal Survival ◽  
Biophysical Studies ◽  
Low Levels ◽  
And Function ◽  
Specific Inhibitors

Plasma membrane Ca2+ pumps (PMCA pumps) are Ca2+-Mg2+ ATPases that expel Ca2+ from the cytosol to extracellular space and are pivotal to cell survival and function. PMCA pumps are encoded by the genes PMCA1, -2, -3, and -4. Alternative splicing results in a large number of isoforms that differ in their kinetics and activation by calmodulin and protein kinases A and C. Expression by 4 genes and a multifactorial regulation provide redundancy to allow for animal survival despite genetic defects. Heterozygous mice with ablation of any of the PMCA genes survive and only the homozygous mice with PMCA1 ablation are embryolethal. Some PMCA isoforms may also be involved in other cell functions. Biochemical and biophysical studies of PMCA pumps have been limited by their low levels of expression. Delineation of the exact physiological roles of PMCA pumps has been difficult since most cells also express sarco/endoplasmic reticulum Ca2+ pumps and a Na+-Ca2+-exchanger, both of which can lower cytosolic Ca2+. A major limitation in the field has been the lack of specific inhibitors of PMCA pumps. More recently, a class of inhibitors named caloxins have emerged, and these may aid in delineating the roles of PMCA pumps.Key words: ATPases, hypertension, caloxin, protein kinase A, protein kinase C, calmodulin.

scholarly journals Insulin responsiveness of glucose transporter 4 in 3T3-L1 cells depends on the presence of sortilin

2013 ◽  
Vol 24 (19) ◽  
pp. 3115-3122 ◽  
Author(s):  
Guanrong Huang ◽  
Dana Buckler-Pena ◽  
Tessa Nauta ◽  
Maneet Singh ◽  
Agnes Asmar ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Sorting ◽  
Glucose Transporter ◽  
Glucose Transporter 4 ◽  
Insulin Stimulation ◽  
Cell Surface Biotinylation ◽  
Undifferentiated Cells ◽  
Insulin Dependent ◽  
Low Levels ◽  
Insulin Responsiveness

Insulin-dependent translocation of glucose transporter 4 (Glut4) to the plasma membrane of fat and skeletal muscle cells plays the key role in postprandial clearance of blood glucose. Glut4 represents the major cell-specific component of the insulin-responsive vesicles (IRVs). It is not clear, however, whether the presence of Glut4 in the IRVs is essential for their ability to respond to insulin stimulation. We prepared two lines of 3T3-L1 cells with low and high expression of myc7-Glut4 and studied its translocation to the plasma membrane upon insulin stimulation, using fluorescence-assisted cell sorting and cell surface biotinylation. In undifferentiated 3T3-L1 preadipocytes, translocation of myc7-Glut4 was low regardless of its expression levels. Coexpression of sortilin increased targeting of myc7-Glut4 to the IRVs, and its insulin responsiveness rose to the maximal levels observed in fully differentiated adipocytes. Sortilin ectopically expressed in undifferentiated cells was translocated to the plasma membrane regardless of the presence or absence of myc7-Glut4. AS160/TBC1D4 is expressed at low levels in preadipocytes but is induced in differentiation and provides an additional mechanism for the intracellular retention and insulin-stimulated release of Glut4.

Sign in / Sign up

Export Citation Format

Share Document