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Microtubule-associated protein function: lessons from expression in Spodoptera frugiperda cells
1Harvard Medical School, Department of Medicine, Brigham and Women's Hospital, Boston.
Cell Motility and the Cytoskeleton
|January 1, 1994
Summary
Neuronal microtubule-associated proteins (MAPs) like MAP2 and tau induce cell processes in Sf9 cells. However, tau’s in vitro properties don’t fully explain its in vivo cell shape changes.
Area of Science:
- Cell Biology
- Neuroscience
- Biochemistry
Background:
- Neuronal microtubule-associated proteins (MAPs) are crucial for neuronal structure and function.
- Understanding the in situ function of MAPs provides insights into cellular morphogenesis.
Purpose of the Study:
- To investigate the in situ function of neuronal MAPs, specifically MAP2 and tau, in Sf9 cells.
- To determine if the in vitro properties of tau fully explain its role in inducing cell shape changes.
Main Methods:
- Expression of neuronal MAPs (MAP2 and tau) in Sf9 insect cells.
- Microscopic analysis of induced cellular phenotypes, including process formation and microtubule organization.
- Comparison with Taxol-induced microtubule assembly.
Main Results:
- Both MAP2 and tau expression induced long, microtubule-bundle-containing processes in Sf9 cells.
- Tau typically induced a single, unbranched process, while MAP2 induced distinct morphological features.
- Microtubule plus ends were distal in induced processes; terminal regions were actin-rich.
- Taxol induced microtubule bundling but not process formation, indicating MAPs are necessary for shape change.
Conclusions:
- The in vitro properties of tau (assembly, stabilization, bundling) do not fully account for its in vivo ability to induce cell shape changes.
- MAP2 and tau exhibit distinct mechanisms in transducing microtubule assembly into altered cell morphology.
- Sf9 cells provide a valuable model for studying the in situ functions of neuronal MAPs.