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University of Helsinki Laboratory of Professor Elina Ikonen

Neuroendocrine Membrane Traffic Research


Contact information:

Nils Bäck
Tel. +358-2941 25265
E-mail: nils dot back
at helsinki dot fi

Street address:
Haartmaninkatu 8
(Biomedicum Helsinki)
00290 Helsinki

Mailing address:
P.O.Box 63
00014 University of Helsinki


Tel: +358-2941 911
Fax +358-2941 25302

Business Identity Code:
(University of Helsinki)


Regulated secretion in neuroendocrine cells

Secretion and endocytosis are continuous processes in all cells. Regulated secretion occurs in cells which need to store their secretory products in secretory granules and release them only upon specific external stimuli. Examples are cells which produce peptide hormones or peptide neurotransmitters. About half of these cells contain PAM (peptidylglycine α-amidating monooxygenase).This enzyme catalyzes the amidation of many bioactive peptides, a modifiction needed for their full activity. In addition, the cytoplasmic domain of PAM regulates the secretion and reuptake of the secretory granule membrane. I study the mechanisms of this regulation in close collaboration with prof. Betty A. Eipper and prof. Richard E. Mains at the University of Connecticut Health Center and prof. Elina Ikonen at the Institute of Biomedicine. Major open questions are how PAM regulates the entry into and exit from multivesicular bodies, transport from endosomes to the trans-Golgi network and reuse of the granule membrane. The wider interest and clinical implication of the studies lie in the recently discovered role of multivesicular body trafficking and signaling in the maintenance of neuronal function and viability.

The figure shows PAM antibody-colloidal gold complexes internalized into multivesicular bodies