Developmentally Regulated Protein Secretion

Regulated secretion of proteins is an important aspect of the developmental program of all multicellular organisms. In Dictyostelium, secretion of the spore coat proteins from the prespore vesicles (PSVs) occurs synchronously at the terminal stage of development. Thus, it is particularly amenable to study using biochemical approaches. We have purified and characterized the prespore vesicles and used a global proteomic approach to identify the component proteins of the vesicles. This is the first example of using proteomics to identify all the proteins in a previously uncharacterized organelle. We have identified approximately 50 proteins, and this has lead to the development of testable hypotheses on how they function to regulate secretion during development.

Selected Publications

Alexander, S., Srinivasan, S., and Alexander, H. (2003). Proteomics opens doors to the mechanisms of developmentally regulated secretion. Mol. Cell. Proteomics. 2:1156-1163. (COVER ARTICLE)

Srinivasan, S., M. Traini, B. Herbert, D. Sexton, J. Harry, H. Alexander K.L.Williams and S. Alexander. (2001). Proteomic analysis of a developmentally regulated secretory vesicle. Proteomics, 1:1119-1127. MEDLINE

Srinivasan, S., K.R. Griffiths, V. McGuire, A. Champion, K.L. Williams and S. Alexander. 2000. The cellulose-binding activity of the PsB multiprotein complex is required for proper assembly of the spore coat and spore viability in Dictyostelium discoideum. Microbiology, 146: 1829-1839. MEDLINE

Srinivasan, S., H. Alexander and S.Alexander. 2000. Crossing the finish line of development: Regulated secretion and assembly of the Dictyostelium spore coat proteins. Trends Cell Biol., 10: 215-219. MEDLINE

Srinivasan, S., H. Alexander and S.Alexander. 1999. The prespore vesicle of Dictyostelium discoideum: Purification, characterization and developmental regulation. J. Biol. Chem., 274: 35823-35831. MEDLINE

McGuire, V. and S. Alexander. 1996. PsB multiprotein complex of Dictyostelium discoideum: Demonstration of cellulose binding activity and order of protein subunit assembly. J. Biol. Chem., 271: 14596-14603. MEDLINE

Alexander, S. 1997. Developmental regulation and function of glycoproteins in Dictyostelium discoideum. In Dictyostelium-a model system for cell and developmental biology. (Y. Maeda, I. Takeuchi and K. Inouye, eds.) Universal Academy Press, Tokyo., 349-362.