 in sustained signaling even after internalization (Barr et al., 2006; Bunnell et al., 2006) Nguyen et al, 2008). This behavior is strikingly similar to the observed movement of MHC-peptide based TCR microclusters, which occurs in the plane of the plasma membrane in the synapse (Varma et al., 2006). However, the anti-CD3ε driven TCR clusters become systematically F-actin independent after formation (Douglass and Vale, 2005). The inclusion of β1 integrin ligands like fibronectin on the surface with anti-CD3ε results in stabilization of the SLP-76 interaction with the TCR clusters and also appears to dampen F-actin dynamics (Nguyen et al., 2008). Integrin ligands generally enhance TCR signaling (Shimizu et al., 1990) and this study suggests that one component of this effect may be stabilization of TCR signaling complexes. There are clearly differences between the polyvalent anti-CD3ε interaction with the TCR complex, which contains two copies of the CD3ε chain (Call et al., 2002), and the monovalent interaction of MHC-peptide ligands with TCR that change requirements for signaling. The transport process in the planar bilayers also creates a very useful lateral segregation of TCR based structures by age with the earliest TCR microclusters in the periphery and the oldest TCR clusters in the cSMAC. Recently, monovalent biotinylation of anti-CD3εhas created a means to achieve such tempero-spatial segregation of TCR signaling complexes by attaching anti-CD3 to planar bilayers with lipid anchored ICAM-1 to form classical synapses with Jurkat cells or polyclonal T cell populations (Kaizuka et al., 2007). This method has contributed to our understanding of the synapse dynamics. We have two quite different ways to study microclusters that are appropriate for different questions and have different degrees of difficulty. It is impossible to say that one is better than the other at this point-it depends upon the experiment. Further study of microclusters in T cell-DC interfaces using advanced confocal methodologies and even in