HPA045679HPA041736HPA025226 D-PASFontana Masson

Sudan Black

Auto-fluorescence

www.proteinatlas.org

The HPR project is funded by

the Knut & Alice Wallenberg

foundation. The atlas is part of

the HUPO Human Antibody

IDENTIFICATION OF PROTEINS IN LIPOFUSCIN USING ANTIBODIES WITHIN THE HUMAN PROTEIN ATLAS 1 Evelina Sjöstedt , Dijana Djureinovic 1 2 1, Jan Mulder and Caroline Kampf

BackgroundThe Human Protein Atlas (HPA) is a research project that aims to visualize the cellular and subcellular location of every human

1protein by using monospecific polyclonal antibodies . This high-throughput approach enables the discovery of new protein distribution profiles and can also provide deeper insights into already known patterns. Here we used HPA antibodies to identify proteins associated with the age pigment lipofuscin.

Lipofuscin is mainly present in post mitotic cells. It consists of lipids, proteins, carbohydrates and a small amount of metals. 2Despite that lipofuscin has been well-known for a long time the exact composition of the protein portion is uncertain .

Cerebral cortex

Heart muscle

Liver

Seminal vesicle

Kidney

Adrenal gland

Histochemical staining of lipofuscin using antibodies, D-PAS, FontanaMasson and Sudan Black show similar results in all tissues.

HPA025226 HPA028498

Autofluorescent lipofuscinconfirmed by immunofluorescence.

Conclusions

All methods; histochemical staining, confocal imaging and Western blot verified that the staining pattern observed by the antibodies was indeed lipofuscin.

The large collection of antibodies produced within the HPA project has proven to be a valuable tool to identify compartments of cellular complexes like lipofuscin.

A number of the previously unknown proteins within lipofuscin have been identified; GGH (HPA025226), MIP18 (HPA041736) and HDGL1 (HPA045679). Thereby a few pieces of the lipofuscin puzzle have been solved.

1. HPA025226, band in liver lysate around 40kDa (predicted mol weights are 36kDa and 18,4kDa.)

2. HPA041736, band in heart muscle lysate around 22kDa (predicted mol weight is 17.7kDa.)

3. HPA045679, band in heart muscle lysate around 26kDa (predicted mol weight is 27,2kDa.)

1. Department of Immunology, Genetics and Pathology, Human Protein Atlas, Science for Life Laboratory, Uppsala University, Uppsala, Sweden2. Department of Neuroscience, Human Protein Atlas, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden

3.1. 2.

References1. A human protein atlas for normal and cancer tissues based on antibody proteomics. Mol Cell Proteomics. 2005 4 (12):1920-32

2. Lipofuscin: Mechanisms of age-related accumulation and influence on cell functions. Free Radical Biology & Medicine, 33 (2002), pp. 611-619