Abstract: Disclosed here is a method for measuring the kinetics (i.e., the molecular flux rates—synthesis and breakdown or removal rates) of a plurality of proteins or organic metabolites inn living systems. The methods may be accomplished in a high-throughput, large-scale automated manner, by using existing mass spectrometric profiling techniques and art well known in the fields of static proteomics and static organeomics, without the need for additional biochemical preparative steps or analytic/instrumental devices.

Abstract: Stable isotope labeling was used to measure dynamics of tubulin incorporation into microtubule subpopulations representing different neuronal compartments in the murine hippocampus. Neuronal microtubules were largely static. Basal turnover was highest in tau-associated (axona) and growth cone), lower in MAP2-associated (somatodendritic), and lowest in cold stable (axonal shaft) subpopulations. Intracerebroventricular glutamate injection stimulated label incorporation into axonal shaft and somatodendritic microtubules, the latter dependent on cAMP-PKA. Hippocampus-dependent memory formation after contextual fear conditioning was accompanied by increased assembly of MAP2- and cold stable-microtubules. Both microtubule assembly and memory formation were inhibited by the microtubule depolymerizing drug, nocodazole. This approach allows for correlation with behavioral measures of learning and memory and for the screening of candidate agents for stimulatory activities on learning memory.

Abstract: The methods of the present invention allow for the measurement of proliferation, clonal expansion trafficking and/or recruitment of lymphocytes into lymphoid tissue in an in vivo setting. Proliferation, clonal expansion, recruitment and/or trafficking of lymphocytes are measured by using stable isotopes to label newly synthesized DNA, isolating the newly-labeled DNA, and quantifying enrichment of the isolated DNA with mass spectrometry or other appropriate techniques. Such methods are useful in screening candidate drugs for stimulatory or inhibitory effects on proliferation, clonal expansion, recruitment and/or trafficking of lymphocytes. The methods also allow for the discovery of therapeutic agents in disorders of immune regulation such as HIV infection and for optimizing vaccine efficacy.