Quantitative analysis of membrane and secretory protein processing and intracellular transport

Quantitative experimental data from studies of intracellular processing and transport of secretory and membrane proteins are only rarely evaluated using kinetic modelling. Instead, the analysis of such data is usually limited to calculating either the apparent half-life or the transit time. Neither of these parameters accurately measures rates of cellular processing or transport. This paper describes a formal approach for the calculation of rate constants, half-lives and lag times for single and sequential processing and transport steps. Generalized kinetic models are presented that can be used to analyse data from both pulse-chase and continuous incubation experiments with labelled amino acids or sugars. The results from a number of published studies are reanalysed using the models to demonstrate the usefulness of kinetic modelling in the routine analysis of experimental data.