MARILYN RESH

..Heterogeneity in the types of membrane subdomains, as well as in the types of lipophilic groups that are attached to proteins, provide an additional level of complexity in the regulation of signaling by membrane bound proteins...

..Finally, general approaches to determining the effect of altered palmitoylation status on YFPP association with membranes and lipid rafts, as well as signal transduction, are described...

..Agents that alter the palmitoylation status of Ras, Wnt and Hh proteins have recently been discovered, and represent the next generation of potential chemotherapeutics...

..Viral recruitment of ESCRT proteins could therefore impact on host cell processes such as receptor downregulation...

..However, the authors show that Cbp-mediated Src suppression is Csk independent. These findings suggest that Cbp is a tumor suppressor whose expression is downregulated during Src-driven cancer progression...

..The identification of the palmitoyl acyltransferases has provided new insights into the biochemistry of this posttranslational process and permitted new substrates to be identified...

..These findings provide new insights into the biochemical and biophysical mechanisms that regulate membrane targeting, trafficking and signaling by lipid-modified proteins...

..Given that MVB exocytosis is an essential host-cell pathway, effective antiviral agents will need to specifically target interaction of Gag with the endocytic pathway without perturbing the normal host-cell trafficking network...

..The biochemistry and cell biology of protein myristoylation, farnesylation and geranylgeranylation is reviewed here, with emphasis on the Src family of tyrosine kinases, Ras proteins and G protein coupled signalling systems...

..Alteration of the levels of Fyn in appropriate target tissues may lead to better treatments for alcoholism and autoimmune disease...

..The use of myristoyl switches and regulated depalmitoylation as mechanisms for achieving reversible membrane binding and regulated signaling will also be explored...

..These studies suggest a strategy to attack HIV assembly by selectively altering the patterns of fatty acid modification...

..Lysine mutants of Fyn that could not be methylated failed to promote cell adhesion and spreading, suggesting that methylation is important for Fyn function...

..These data suggest a role for palmitoylation in restricting Spitz diffusion, allowing its local concentration to reach the threshold required for biological function...

..Moreover, these studies reveal a novel mode of action of MbetaCD, in addition to its ability to disrupt membrane rafts...

..These data reveal the heterogeneous nature of S-acylation in vivo and illustrate the power of mass spectrometry for identification of key regulatory protein modifications...

..These results indicate that HIV-1 Gag can impinge upon the functioning of the cellular vacuolar protein sorting pathway and reveal yet another facet of the intricate effects of HIV-1 infection on host cell physiology...

..All of the pocket mutants exhibited decreased kinase activity. We concluded that myristoylation and the pocket residues regulate c-Src, but in a manner very different from that for c-Abl...

..Taken together, these data indicate that activation of PI 3-kinase by KL promotes binding of the Dok pleckstrin homology domain and Dok-1 recruitment to the plasma membrane where Dok-1 is phosphorylated by Src and/or Tec family kinases...

..We propose that HIV-1 Gag contains a signal that promotes interaction with the cellular endocytic machinery and that the site of particle production is regulated by the subcellular distribution of cholesterol...

..Thus, compartmentalization in lipid rafts is necessary to couple the alpha6beta4 integrin to a palmitoylated SFK and promote EGF-dependent mitogenesis...

..These data indicate that Anx2 is not required for HIV-1 assembly or Gag processing but rather plays a cell type-dependent role in regulating production of infectious HIV-1 by macrophages...

..These studies identify a novel transit station through which Gag traffics en route to particle assembly and highlight the importance of KIF4 in regulating HIV-1 Gag trafficking and stability...

..These data suggest that the synergy between c-Src and EGFR also occurs as these two kinases traffic together, and that their co-localization promotes EGFR-mediated signaling...

..We propose that the regulation of Gag association with MVB-like compartments regulates the site of HIV-1 budding and particle formation...

..This study establishes Hhat as a bona fide Shh PAT and serves as a model for understanding how secreted morphogens are modified by distinct PATs...

..Taken together, these results suggest a linear signal transduction pathway of integrin-Fyn-Rho family GTPases that controls morphologic differentiation of oligodendrocytes...

....

..These results suggest that lack of palmitoylation may influence the partitioning of apoB48 between microsomal membranes and microsomal lumen, but it does not compromise the ability of apoB48 to assemble lipoproteins...

..These results demonstrate the simplicity and utility of SILAC as a method to quantify dynamic changes in phosphorylation at specific sites in response to stimuli or drug treatment in cell culture...

..We will test the abilities of wt, dominant negative and fatty acylation mutants of Fyn to promote the oligodendrocyte differentiation process. ..

..These experiments will complement the biochemical studies in Aims 1 and 2 and are likely to provide a fascinating view of Gag movement and dynamics in live cells. ..

..The activity of the above proteins in human glioma tumor samples will be determined. ..

..We are therefore requesting continuation of this grant, with a level of funding to support a total of 8 first and second year graduate students. ..

..Multicolor imaging with site-specific fluorescein derivatives (FLASH and ReAsH) will be used to determine the order in which Gag assembly sites are formed and maintained in the cell. ..

..Multicolor imaging with site-specific fluorescein derivatives (FLASH and ReAsH) will be used to determine the order in which Gag assembly sites are formed and maintained in the cell. ..

..The proposed studies will help us understand how Hh proteins work in normal and malignant cells and will aim to develop Hh inhibitors that could potentially be clinically useful as anti-tumor agents in Hh driven malignancies. ..

..We will test whether SFKs interact with components of the endocytic machinery en route to the plasma membrane. ..

..abstract_text> ..