ITK (IL-2

Injection of aspirated fat is now the most commonly used technique for the filling of depressed areas. Partial absorption of the injected fat is the main limitation of this procedure. Cariel T.M. is an enriched serum-free cell culture medium, its ability to enhance the survival of human aspirated fat grafts was investigated in the nude mouse model. A volume of 0.75-cc Cariel preprocessed fat was injected under the scalp skin of 16 nude mice in the experimental group, and the same volume of saline preprocessed fat was injected to 15 control group of mice. Significant maintenance of the weight, 46 percent in the experimental group compared with 29 percent in the control group (p < 0.008), and the volume, 44 percent in the experimental group compared with 31 percent in the control group (p < 0.026), was observed, after 15 weeks, in this newly used model. It seems that addition of the nutrients enriched with anabolic hormones enabled the survival and take of more adipose cells in the graft.

SLP-76 forms part of a hematopoietic-specific adaptor protein complex, and is absolutely required for T cell development and activation. T cell receptor (TCR)-induced activation of phospholipase C-␥1 (PLC-␥1) depends on three features of SLP-76: the N-terminal tyrosine phosphorylation sites, the Gads-binding site, and an intervening sequence, denoted the P-I region, which binds to the SH3 domain of PLC-␥1 (SH3 PLC ) via a low affinity interaction. Despite extensive research, the mechanism whereby SLP-76 regulates PLC-␥1 remains uncertain. In this study, we uncover and explore an apparent paradox: whereas the P-I region as a whole is essential for TCRinduced activation of PLC-␥1 and nuclear factor of activated T cells (NFAT), no particular part of this region is absolutely required. To better understand the contribution of the P-I region to PLC-␥1 activation, we mapped the PLC-␥1-binding site within the region, and created a SLP-76 mutant that fails to bind SH3 PLC , but is fully functional, mediating TCR-induced phosphorylation of PLC-␥1 at tyrosine 783, calcium flux, and nuclear factor of activated T cells activation. Unexpectedly, full functionality of this mutant was maintained even under less than optimal stimulation conditions, such as a low concentration of the anti-TCR antibody. Another SLP-76 mutant, in which the P-I region was scrambled to abolish any sequence-dependent protein-binding motifs, also retained significant functionality. Our results demonstrate that SLP-76 need not interact with SH3 PLC to activate PLC-␥1, and further suggest that the P-I region of SLP-76 serves a structural role that is sequence-independent and is not directly related to protein-protein interactions.

Phospholipase C-␥1 (PLC-␥1) activation depends on a heterotrimeric complex of adaptor proteins composed of LAT, Gads, and SLP-76. Upon T cell receptor stimulation, a portion of PLC-␥1 is recruited to a detergent-resistant membrane fraction known as the glycosphingolipid-enriched membrane microdomains (GEMs), or lipid rafts, to which LAT is constitutively localized. In addition to LAT, PLC-␥1 GEM recruitment depended on SLP-76, and, in particular, required the Gads-binding domain of SLP-76. The N-terminal tyrosine phosphorylation sites and P-I region of SLP-76 were not required for PLC-␥1 GEM recruitment, but were required for PLC-␥1 phosphorylation at Tyr A trio of hematopoiesis-specific adaptors, including LAT, 3 Gads, and SLP-76, serve as pathway-specific regulators of phospholipase C-␥1 (PLC-␥1) (1). PLC-␥1 is a ubiquitous enzyme, regulated by phosphorylation at Tyr 775 and Tyr 783 (2-4) and involved in many different signaling pathways (5, 6). When activated, PLC-␥1 hydrolyzes phosphatidylinositol 4,5-bisphosphate, producing the second messengers inositol 1,4,5-trisphosphate and diacylglycerol, which trigger calcium flux and contribute to protein kinase C and Ras activation, respectively. In T cells, the coordinated activity of calcium-and Rasdependent signaling pathways leads to the activation of NFAT, a regulator of interleukin-2 transcription (7,8). Given the importance of PLC-␥1-dependent signaling events, it is not surprising that the activation of PLC-␥1 is tightly regulated.The LAT, Gads, and SLP-76 adaptor proteins appear to constitute an integrated signaling unit that couples immunoreceptormediated activation of cytoplasmic tyrosine kinases to the activation of PLC-␥1 (1, 9). The use of three adaptor proteins to regulate one enzyme is a recurrent theme in complex signaling pathways. In a similar fashion, three adaptors (FRS2, Grb2, and Gab1) cooperate to activate phosphatidylinositol-3-kinase in the fibroblast growth factor receptor signaling pathway (10, 11). Evidence that LAT, Gads, and SLP-76 work in concert includes their similar expression patterns and localization to the same signaling complex; similar signaling defects observed in LATand SLP-76-deficient T cell lines; and similar T cell and mast cell phenotypes observed in LAT-, SLP-76-, and Gads-deficient mice (1,9,12). Most convincingly, SLP-76 alone cannot reconstitute B cell receptor signaling in a B cell line lacking the SLP-76 analog BLNK (B cell linker); rather, cotransfection of SLP-76, LAT, and Gads is required (13,14). Over the past years, the mechanisms whereby these adaptors mediate the activation of PLC-␥1 are beginning to be understood, as summarized briefly below.LAT, a transmembrane adaptor protein, is constitutively localized to specialized membrane microdomains known as glycosphingolipid-enriched membrane domains (GEMs), lipid rafts, or detergent-insoluble glycolipid-enriched membrane domains (15, 16). Upon T cell receptor (TCR) stimulation, LAT is heavily tyrosine-phosphorylated (17, 18), and a motif encompassing LAT phosph...