High molecular weight polypeptides related to dynein heavy chains in Nicotiana tabacum pollen tubes

1995 ◽  
Vol 108 (3) ◽  
pp. 1117-1125
Author(s):  
A. Moscatelli ◽  
C. Del Casino ◽  
L. Lozzi ◽  
G. Cai ◽  
M. Scali ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Nicotiana Tabacum ◽  
Pollen Tube ◽  
High Molecular Weight ◽  
Pollen Tubes ◽  
Biochemical Properties ◽  
Bovine Brain ◽  
Atp Binding ◽  
Heavy Chains ◽  
Dynein Heavy Chains

Nicotiana tabacum pollen tubes contain two high molecular weight polypeptides (about 400 kDa), which are specifically expressed during pollen germination and pollen tube growth in BK medium. The high molecular weight doublet resembles the dynein heavy chains in some biochemical properties. Sedimentation profiles of pollen tube extracts show that the high molecular weight bands have sedimentation coefficients of 22 S and 12 S, respectively. ATPase assay of sedimentation fractions shows an activity ten times higher when stimulated by the presence of bovine brain microtubules in fractions containing the 22 S high molecular weight polypeptide. Both these high molecular weight polypeptides can bind microtubules in an ATP-dependent fashion. A mouse antiserum to a synthetic peptide reproducing the sequence of the most conserved ATP-binding site among dynein heavy chains recognized the two high molecular weight polypeptides. Therefore these polypeptides have sequences immunologically related to the ATP binding sites of dynein heavy chains.

Heterogeneity of High-molecular-weight Human Salivary Mucins

2000 ◽  
Vol 14 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G.D. Offner ◽  
R.F. Troxler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Biochemical Properties ◽  
Salivary Proteins ◽  
Molecular Weights ◽  
Structural Framework ◽  
Buccal Epithelial Cells ◽  
Membrane Bound ◽  
Membrane Spanning ◽  
Micro Organisms

The existence of high-molecular-weight glycoproteins in saliva and salivary secretions has been recognized for nearly 30 years. These proteins, called mucins, are essential for oral health and perform many diverse functions in the oral cavity. Mucins have been intensively studied, and much has been learned about their biochemical properties and their interactions with oral micro-organisms and other salivary proteins. In the past several years, the major high-molecular-weight mucin in salivary secretions has been identified as MUC5B, one of a family of 11 human mucin gene products expressed in tissue-specific patterns in the gastrointestinal, respiratory, and reproductive tracts. MUC5B is one of four gel-forming mucins which exist as multimeric proteins with molecular weights greater than 20-40 million daltons. The heavily glycosylated mucin multimers form viscous layers which protect underlying epithelial surfaces from microbial, mechanical, and chemical assault. Another class of mucin molecules, the membrane-bound mucins, is structurally and functionally distinct from the gel-forming mucins. These proteins do not form multimers and can exist as both secreted and membrane-bound forms, with the latter anchored to epithelial cell membranes through a short membrane-spanning domain. In the present work, we show that two of the membrane-bound mucins, MUC1 and MUC4, are expressed in all major human salivary glands as well as in buccal epithelial cells. While the functions of these mucins in the oral environment are not understood, it is possible that they form a structural framework on the cell surface which not only is cytoprotective, but also may serve as a scaffold upon which MUC5B, and possibly other salivary proteins, assemble.

The high-molecular-weight proteins of bovine brain plain synaptic vesicles

1987 ◽  
Vol 12 (7) ◽  
pp. 635-640
Author(s):  
Paul E. March ◽  
Edna Antonian ◽  
Diane M. Schneider ◽  
David M. Rothwarf ◽  
Edward R. Thornton
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Synaptic Vesicles ◽  
Bovine Brain ◽  
High Molecular Weight Proteins

Regulation of high molecular weight bovine brain neutral protease by phospholipids in vitro

2005 ◽  
Vol 272 (1-2) ◽  
pp. 145-149 ◽  
Author(s):  
V. Chauhan ◽  
A. M. Sheikh ◽  
A. Chauhan ◽  
W. D. Spivack ◽  
M. D. Fenko ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Bovine Brain ◽  
Neutral Protease

Biochemical properties of some high molecular weight subunits of wheat glutenin

1985 ◽  
Vol 3 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Johannes H.E. Moonen ◽  
Auke Scheepstra ◽  
Aris Graveland
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Biochemical Properties

The kinesin-immunoreactive homologue from Nicotiana tabacum pollen tubes: Biochemical properties and subcellular localization

Planta ◽  
1993 ◽  
Vol 191 (4) ◽  
pp. 496-506 ◽  
Author(s):  
G. Cai ◽  
A. Bartalesi ◽  
C. Del Casino ◽  
A. Moscatelli ◽  
A. Tiezzi ◽  
...  
Keyword(s):  
Nicotiana Tabacum ◽  
Subcellular Localization ◽  
Pollen Tubes ◽  
Biochemical Properties

Confocal image analysis of spatial variations in immunocytochemically identified calmodulin during pollen hydration, germination and pollen tube tip growth in Nicotiana tabacum L.

Zygote ◽  
1994 ◽  
Vol 2 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Uday K. Tirlapur ◽  
Monica Scali ◽  
Alessandra Moscatelli ◽  
Cecilia Del Casino ◽  
Gianpiero Cai ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nicotiana Tabacum ◽  
Pollen Tube ◽  
Pollen Tubes ◽  
Spatial Variations ◽  
Tube Growth ◽  
Confocal Scanning Laser Microscopy ◽  
Pollen Hydration ◽  
Confocal Scanning Laser ◽  
High Level

SummaryUsing monoclonal anti-calmodulin antibodies in conjunction with confocal scanning laser microscopy we have analysed the spatial variations in the distribution pattern of calmodulin (CaM) during the sequential events of pollen hydration, germination and tube growth in Nicotiana tabacum. These immunocytochemical observations have been complemented by immunochemical studies wherein the anti-calmodulin antibody raised against pea CaM recognises a polypeptide of c. 18 kDa in the pollen extracts. Digitisation of confocally acquired optical sections of immunofluorescence images reveals that in hydrated pollen a high level of CaM is consistently present in the region of the germinal apertures. Subsequently, with the onset of germination a high CaM concentration was found associated with the plasma membrane of the germination bubble and in the cytoplasm in its vicinity, while in the vegetative cytoplasm a weak diffuse and intense punctate signal was registered. CaM immunostain was also detected in association with the plasma membrane of the tube tips in both short and long pollen tubes. Furthermore, the cytosol of the tubes invariably manifested an apically focused CaM gradient. We were, however, unable to detect any vacuolar association of CaM in the older regions of the pollen tubes. Although punctate immunostain was obvious across the pollen tube numerous punctate structures were invariably present in the extreme tip. The possible implications of these findings in development of cell polarity, polarised growth, maintenance of calcium homeostasis and CaM interactions with other mechanochemical motor proteins in effecting propulsion of organelles during pollen hydration, germination and pollen tube growth are discussed.

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