scholarly journals THE STRUCTURE, ORIGIN, ISOLATION, AND COMPOSITION OF THE TUBULAR MASTIGONEMES OF THE OCHROMONAS FLAGELLUM

1971 ◽  
Vol 50 (2) ◽  
pp. 362-384 ◽  
Author(s):  
G. Benjamin Bouck

The structure, assembly, and composition of the extracellular hairs (mastigonemes) of Ochromonas are detailed in this report. These mastigonemes form two lateral unbalanced rows, each row on opposite sides of the long anterior flagellum. Each mastigoneme consists of lateral filaments of two distinct sizes attached to a tubular shaft. The shaft is further differentiated into a basal region at one end and a group of from one to three terminal filaments at the free end. Mastigoneme ontogeny as revealed especially in deflagellated and regenerating cells appears to begin by assembly of the basal region and shaft within the perinuclear continuum. However, addition of lateral filaments to the shaft and extrusion of the mastigonemes to the cell surface is mediated by the Golgi complex. The ultimate distribution of mastigonemes on the flagellar surface seems to be the result of extrusion of mastigonemes near the base of the flagellum, and it is suggested that mastigonemes are then pulled up the flagellum as the axoneme elongates. Efforts to characterize mastigonemes biochemically after isolation and purification on cesium chloride (CsCl) followed by electrophoresis on acrylamide gels have demonstrated what appear to be a single major polypeptide and several differentially migrating carbohydrates. The polypeptide is not homologous with microtuble protein. The functionally anomalous role of mastigonemes in reversing flagellar thrust is discussed in relation to their distribution relative to flagellar anatomy and to the plane of flagellar undulations.

2000 ◽  
Vol 97 (15) ◽  
pp. 8375-8380 ◽  
Author(s):  
S. Heino ◽  
S. Lusa ◽  
P. Somerharju ◽  
C. Ehnholm ◽  
V. M. Olkkonen ◽  
...  

2013 ◽  
Vol 202 (2) ◽  
pp. 241-250 ◽  
Author(s):  
Yuichi Wakana ◽  
Julien Villeneuve ◽  
Josse van Galen ◽  
David Cruz-Garcia ◽  
Mitsuo Tagaya ◽  
...  

Here we report that the kinesin-5 motor Klp61F, which is known for its role in bipolar spindle formation in mitosis, is required for protein transport from the Golgi complex to the cell surface in Drosophila S2 cells. Disrupting the function of its mammalian orthologue, Eg5, in HeLa cells inhibited secretion of a protein called pancreatic adenocarcinoma up-regulated factor (PAUF) but, surprisingly, not the trafficking of vesicular stomatitis virus G protein (VSV-G) to the cell surface. We have previously reported that PAUF is transported from the trans-Golgi network (TGN) to the cell surface in specific carriers called CARTS that exclude VSV-G. Inhibition of Eg5 function did not affect the biogenesis of CARTS; however, their migration was delayed and they accumulated near the Golgi complex. Altogether, our findings reveal a surprising new role of Eg5 in nonmitotic cells in the facilitation of the transport of specific carriers, CARTS, from the TGN to the cell surface.


1991 ◽  
Vol 30 (06) ◽  
pp. 290-293 ◽  
Author(s):  
P. Maleki ◽  
A. Martinezi ◽  
M. C. Crone-Escanye ◽  
J. Robert ◽  
L. J. Anghileri

The study of the interaction between complexed iron and tumor cells in the presence of 67Ga-citrate indicates that a phenomenon of iron-binding related to the thermodynamic constant of stability of the iron complex, and a hydrolysis (or anion penetration) of the interaction product determine the uptake of 67Ga. The effects of various parameters such as ionic composition of the medium, nature of the iron complex, time of incubation and number of cells are discussed.


2001 ◽  
Vol 155 (3) ◽  
pp. 369-380 ◽  
Author(s):  
Hein Sprong ◽  
Sophie Degroote ◽  
Tijs Claessens ◽  
Judith van Drunen ◽  
Viola Oorschot ◽  
...  

A;lthough glycosphingolipids are ubiquitously expressed and essential for multicellular organisms, surprisingly little is known about their intracellular functions. To explore the role of glycosphingolipids in membrane transport, we used the glycosphingolipid-deficient GM95 mouse melanoma cell line. We found that GM95 cells do not make melanin pigment because tyrosinase, the first and rate-limiting enzyme in melanin synthesis, was not targeted to melanosomes but accumulated in the Golgi complex. However, tyrosinase-related protein 1 still reached melanosomal structures via the plasma membrane instead of the direct pathway from the Golgi. Delivery of lysosomal enzymes from the Golgi complex to endosomes was normal, suggesting that this pathway is not affected by the absence of glycosphingolipids. Loss of pigmentation was due to tyrosinase mislocalization, since transfection of tyrosinase with an extended transmembrane domain, which bypassed the transport block, restored pigmentation. Transfection of ceramide glucosyltransferase or addition of glucosylsphingosine restored tyrosinase transport and pigmentation. We conclude that protein transport from Golgi to melanosomes via the direct pathway requires glycosphingolipids.


1999 ◽  
Vol 11 (12) ◽  
pp. 2043-2052 ◽  
Author(s):  
Kazuhito Toyo-oka ◽  
Yumi Yashiro-Ohtani ◽  
Cheung-Seog Park ◽  
Xu-Guang Tai ◽  
Kensuke Miyake ◽  
...  

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