Introducing the HPA image of the week! Each week we will pick an image we find particularly interesting and briefly discuss it. This series will particularly focus on images brought to us by citizen scientists working on Project Discovery, though may include images from other projects in the atlas as well.

This week's image is brought to us by citizen scientist CalebAyrania who found this staining playing Project Discovery and correctly identified the antibody as labeling centrosomes in mitotic cells (cells undergoing division). This staining was observed in CACO-2 colorectal epithelial adenocarcinoma cells.

This is an antibody targets HSPA8 (heat shock 70kDa protein 8, ENSG00000109971). To our knowledge, HSPA8 was first mentioned as being part of the centrosome in 1996 by Brown et al. More recently, HSPA8 was found in an affinity capture mass spectrometry experiment with cell division cycle 20 (CDC20), suggesting that the two may interact either directly or in complex with common proteins ( Fogeron et al. 2013 ).

CDC20 is a known component of centrosomes, and is an anaphase-promoting complex activator, one of the key stages of mitosis. Interestingly, CDC20 over expression has been shown to play a role in adenocarcinoma differentiation and progression (Chang et al. 2012 ). This is the same cancer type as CACO-2 cells in which this staining pattern was observed.

HSPA8 was previously uncharacterized in the Protein Atlas, and we thank CalebAyrania and all the participants of Project Discovery for their contribution to science!

Devin Sullivan