Neutrophil Granulocytes: A Model for Analyzing the Relationship Between Shape, Function and Cytoskeletal Structure

Summary

The results available so far allow to distinguish between three major groups of responses on the basis of the type of shape changes, functional activity and distribution of F-actin.

• 1. Agents capable of polarizing cells, such as cheraotactic peptides, microtubule disassembling agents and the protein kinase inhibitor H-7 elicit, at appropriate concentrations, a marked chemokinetic response, but little if any fluid pinocytosis.

• 2. Activators of protein kinase C such as PMA and diacylglycerols stimulate pinocytosis substantially but tend to inhibit locomotion or chemotaxis as an immediate response.

• 3. Circus movement may occur in response to D₂O. These cells show little or no stimulation of locomotion or pinocytosis. Thus the functional significance of this motor response remains to be elucidated.

The responses to chemotactic peptides, activators of protein kinase C (PMA, DAG’s) or the protein kinase inhibitor H-7 are as sociated with an increase in cytoskeletal actin. Furthermore, there is a redistribution of F-actin in stimulated cells, showing a similar diversity as the morphology of the shape changes.