Evidence for firm linkages between microtubules and membrane-bounded vesicles.

Abstract

Direct evidence is presented in support of the widely held idea that membrane-bounded vesicles can bind firmly to microtubules. This is shown in P. caudatum which contains ribbons of straight microtubules located in open cytoplasm and uniquely associated with the disk-shaped vesicles. These vesicles frequently lie flat against the face of the ribbons at a constant distance of 30-40 nm. Under certain conditions the ribbons are compressed into zigzag pattern, but the vesicles continue to maintain their 30-40 nm spacing with the tubules and The author's interpretation of this phenomena is that the vesicles and the microtubules are strongly bound together. This interaction appears to be via a filamentous material rather than bridges.

Ultrastructural characteristics of tuft cells in mouse gallbladder epithelium

“…In the intestinal brush border, actin filaments form the core of the microvilli and are attached to the surround ing membrane at the microvillar tip [Ishikawa et al, 1969;Mooseker, 1974: Mooseker andTilney, 1975], The microtubules which consist of tubulin are widely distributed in eukaryotic cells. Their functions include participation in ciliary motility, chromosome movement dur ing mitosis, axonal flow in neurones, and intra cellular movements and secretory phenomena in various cells [Dustin, 1972;Allen, 1975;Salir, 1975;/noué and Ritter, 1975]. The well-known function of the gallbladder is to store and concentrate bile.…”

Mitochondria are associated with microtubules and not with intermediate filaments in cultured fibroblasts.

“…Axons are, however, specialized structures in which intracellular transport mechanisms are especially highly developed, and it is therefore a question whether similar interactions between microtubules and mitochondria occur more generally in nonneuronal cells. In particular, in amorphous cells without a high degree of organization of the cytoskeleton, it may be difficult to observe cross-bridges between microtubules and certain membrane-bound organelles by electron microscopy even though indirect evidence for the existence of linkages is strong (1). In such cases, the technique ofimmunofluorescence, although its resolution is much lower than that of electron microscopy, may nevertheless have advantages in giving an overview of the distributions of two different intracellular components in the same cell.…”

“…refs. [1][2][3][4][5][6][7][8][9][10], including the mitochondria. Such functions might be mediated by one or more kinds ofmolecular interactions between microtubules and the several organelles.…”

Cytoskeleton, microtubules, tubulin and colchicine : A review.

“…Some authors' ideas that non protein and enzymic components which could be found in microtubule extracts are impurities have been the current opinion in this subject (Murphy et al 1983, Snyder and McIntosh 1976, Eipper 1972). However, clear structural associations between these fibrous protein assemblies and membranes are present (Marchant 1978, Esau and Hoefert 1980, Allen 1975, Franke 1971, Bird 1976, Aufderheide 1980, Heggeness et al 1978, Raine et al 1971, Ball and Singer 1982, Bell 1978, Smith et al 1977, Jarlfors and Smith 1969. Therefore, evidences that emphasize membranous nature of these fibrous assemblies were added to this review.…”