The protein tyrosine kinase, Lck plays a pivotal role in mediating signals generated through the T cell antigen receptor complex (TCR). Lck is a member of the Src family of tyrosine kinases. Several structural features of Lck mediate its function, including its catalytic domain, its src- homology 2 (SH2) and 3 (SH3) domains and its covalent modification by palmitic acid. Much recent interest in palmitoylation as a regulatory modification of Src kinases has been generated and a significant portion of this revised application is dedicated to investigating the role of palmitoylation in Lck function. Strategies are presented for determining the effect of surface receptor (e.g., TCR and CD4) engagement on the palmitoylation rate of Lck and for investigating the contribution hydrophobicity makes to Lck function by utilizing a novel synthetic analog of palmitic acid. Lck is also modified by phosphorylation on both serine and tyrosine residues and its tyrosine phosphorylation regulates its catalytic activity. In contrast little information is available concerning the role serine phosphorylation plays in mediating Lck function. Lck becomes serine phosphorylated following TCR ligation and at the mitotic phase of the cell cycle. We propose to investigate the role serine phosphorylation plays in Lck functioning by generating mutants of Lck that lack serine phosphorylation sites as well as mutants that mimic serine phosphorylated Lck. Strategies are presented: 1) to identify the sites of mitotic serine phosphorylation in Lck and the responsible kinase(s); 2) to define a role for the serine phosphorylation of Lck; and, 3) to define and characterize functions for mitotic Lck. These studies will further our understanding of the regulatory role of palmitoylation and serine phosphorylation in Lck function as well as our understanding of the function of Lck at mitosis. They will contribute information to what appears to be an emerging linkage between signaling pathways initiation entry into the cell cycle and events regulating the final stages of cell division.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Program Officer
Marino, Pamela
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Purdue University
Schools of Pharmacy
West Lafayette
United States
Zip Code
Jennings, Benjamin C; Nadolski, Marissa J; Ling, Yiping et al. (2009) 2-Bromopalmitate and 2-(2-hydroxy-5-nitro-benzylidene)-benzo[b]thiophen-3-one inhibit DHHC-mediated palmitoylation in vitro. J Lipid Res 50:233-42
Li, Manqing; Ong, Su Sien; Rajwa, Bartek et al. (2008) The SH3 domain of Lck modulates T-cell receptor-dependent activation of extracellular signal-regulated kinase through activation of Raf-1. Mol Cell Biol 28:630-41
Krzysiak, Amanda J; Rawat, Diwan S; Scott, Sarah A et al. (2007) Combinatorial modulation of protein prenylation. ACS Chem Biol 2:385-9
Geahlen, Robert L; Handley, Misty D; Harrison, Marietta L (2004) Molecular interdiction of Src-family kinase signaling in hematopoietic cells. Oncogene 23:8024-32
Hawash, Ibrahim Y; Kesavan, Kamala P; Magee, Anthony I et al. (2002) The Lck SH3 domain negatively regulates localization to lipid rafts through an interaction with c-Cbl. J Biol Chem 277:5683-91
Kesavan, Kamala P; Isaacson, Christina C; Ashendel, Curtis L et al. (2002) Characterization of the in vivo sites of serine phosphorylation on Lck identifying serine 59 as a site of mitotic phosphorylation. J Biol Chem 277:14666-73
Hawash, Ibrahim Y; Hu, X Eric; Adal, Adiam et al. (2002) The oxygen-substituted palmitic acid analogue, 13-oxypalmitic acid, inhibits Lck localization to lipid rafts and T cell signaling. Biochim Biophys Acta 1589:140-50
Pathan, N I; Geahlen, R L; Harrison, M L (1996) The protein-tyrosine kinase Lck associates with and is phosphorylated by Cdc2. J Biol Chem 271:27517-23
Pathan, N I; Ashendel, C L; Geahlen, R L et al. (1996) Activation of T cell Raf-1 at mitosis requires the protein-tyrosine kinase Lck. J Biol Chem 271:30315-7
Ford, C E; Furlong, M T; Geahlen, R L et al. (1994) Signaling-induced association of a tyrosine-phosphorylated 36-kDa protein with p50csk. J Biol Chem 269:30378-85

Showing the most recent 10 out of 12 publications