The Mammalian Cell as a Macromolecular Assembly

High resolution spot scan imaging of frozen, hydrated actin bundles with 400kV electrons

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122964 ◽

1992 ◽

Vol 50 (1) ◽

pp. 512-513

Author(s):

J. Jakana ◽

M.F. Schmid ◽

P. Matsudaira ◽

W. Chiu

Keyword(s):

High Resolution ◽

Binding Proteins ◽

Actin Binding ◽

Eukaryotic Cells ◽

Dimensional Structure ◽

Structural Basis ◽

Actin Bundle ◽

Actin Bundles ◽

3 Dimensional ◽

Macromolecular Assembly

Actin is a protein found in all eukaryotic cells. In its polymerized form, the cells use it for motility, cytokinesis and for cytoskeletal support. An example of this latter class is the actin bundle in the acrosomal process from the Limulus sperm. The different functions actin performs seem to arise from its interaction with the actin binding proteins. A 3-dimensional structure of this macromolecular assembly is essential to provide a structural basis for understanding this interaction in relationship to its development and functions.

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Metabolic biotinylation of mammalian cell receptors for imaging

Protocol Exchange ◽

10.1038/nprot.2006.132 ◽

2006 ◽

Author(s):

Bakhos A. Tannous ◽

Jan Grimm ◽

Katherine Perry ◽

Ralph Weissleder ◽

Xandra O. Breakefield

Keyword(s):

Mammalian Cell ◽

Cell Receptors

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The Influence of Glycosylation on the Catalytic and Fibrinolytic Properties of Pro-Urokinase

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646314 ◽

1992 ◽

Vol 68 (05) ◽

pp. 539-544 ◽

Cited By ~ 22

Author(s):

Catherine Lenich ◽

Ralph Pannell ◽

Jack Henkin ◽

Victor Gurewich

Keyword(s):

Escherichia Coli ◽

Mammalian Cell ◽

Human Gene ◽

Culture Media ◽

Mammalian Cell Culture ◽

Glycosylation Site ◽

Clot Lysis ◽

Cell Culture Media ◽

E Coli ◽

The Uk

SummaryWe previously found that human pro-UK expressed in Escherichia coli is more active in fibrinolysis than recombinant human pro-UK obtained from mammalian cell culture media. To determine whether this difference is related to the lack of glycosylation of the E. coli product, we compared the activity of E. coli-derived pro-UK [(-)pro-UK] with that of a glycosylated pro-UK [(+)pro-UK] and of a mutant of pro-UK missing the glycosylation site at Asn-302 [(-) (302) pro-UK]. The latter two pro-UKs were obtained by expression of the human gene in a mammalian cell. The nonglycosylated pro-UKs were activated by plasmin more efficiently (≈2-fold) and were more active in clot lysis (1.5-fold) than the (+)pro-UK. Similarly, the nonglycosylated two-chain derivatives (UKs) were more active against plasminogen and were more rapidly inactivated by plasma inhibitors than the (+)UK.These findings indicate that glycosylation at Asn-302 influences the activity of pro-UK/UK and could be the major factor responsible for the enhanced activity of E. coli-derived pro-UK.

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