Mechanisms of T cell motility and arrest: deciphering the relationship between intra- and extracellular determinants.
T lymphocytes are capable of rapid motility in vitro and in vivo. Upon antigen recognition, they may stop crawling and form a stable cell-cell contact called the 'immunological synapse' (IS). However, it is becoming clear that this outcome may not occur with the reliability that was once presumed. T cells, particularly naïve cells, are apparently triggered partly 'on the fly' during short contacts with peptide-MHC (pMHC) bearing antigen-presenting cells (APCs) and are also influenced in both activity and synapse duration by a multitude of external cues. Underlying the emerging issues is a paucity of data concerning the cell biology of T lymphocytes. Here, we review the molecular mechanisms of crawling and adhesion versus the various potential modes of 'stopping' in T lymphocytes. Both motility and arrest involve similar processes: adhesion, actin elongation and internal tension control, but with different coordination. We will attempt to integrate this with the known and potential external cues that signal for T cell motility versus stopping to form a synapse in vivo. Finally, we discuss how this interplay may give rise to unexpectedly complex motile and morphological behavior.
Friedman
Rachel S
RS
Department of Pathology, University of California at San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143-0511, USA.
Jacobelli
Jordan
J
Krummel
Matthew F
MF
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D002465:Cell Movement / Q000276:immunology*; D000939:Epitopes / Q000276:immunology*; D045604:Extracellular Fluid / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007424:Intracellular Fluid / Q000276:immunology* / Q000378:metabolism; D036641:Microscopy, Fluorescence, Multiphoton; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology*
D000939:Epitopes