Project V

Analysis of mouse models and osteoclast function with lysosomal deficiencies.

David Massa Lopez

My name is David Massa Lopez and I am from Spain, from the city of Barcelona. I am in the middle of the picture below. I did my Biology degree at the University of Barcelona and I did a Master of Molecular Biotechnology at the same University. I performed my Masters project in the Cancer Epigenetics Biology Program (PEBC) in Bellvitge, and my studies were focused on the characterization of RANK receptor in PC-3/Mc and PC-3/S cell lines. Since May 2014 I am the Early Stage Researcher located in Kiel (Germany), at the Biochemistry department of Christian Albrechts Universität. When I am not in the lab I like to spend time with my friends and family, play tennis and travel whenever I have the opportunity to do it. I can be reached by email on

Paul Saftig

I am Paul Saftig, the PI and supervisor and am to the left of David in the picture below. I have been involved in research on lysosomes for 20 years. The overall research areas in my laboratory include proteolytic events at the cell surface, lysosome biology, lysosomal storage disorders and Alzheimer’s disease. When I am not in the lab I enjoy playing and following soccer and spending time with friends and family. I can be reached via email on

Markus Damme

I am Markus Damme, the co-supervisor and am to the right of David in the picture below. I have experience in research on lysosomes, lysosomal proteins and lysosome-related diseases. I moved to Kiel in May 2013 and before that I worked in Göttingen and Bielefeld (Germany). My current research focuses on the characterization of new lysosomal membrane proteins of unknown function I enjoy nature and when I am not in the lab I love to spend time outside. I can be contacted by email on

Our Project

The general aim of this project is to get a deeper insight into the function of lysosomal membrane proteins in the biology of osteoclasts. The specific focus of the project is the newly identified lysosomal membrane protein Major facilitator superfamily domain-containing protein 1 (Mfsd1).   According to high-throughput gene expression profiling analysis this protein shows highest expression in osteoclasts compared to other bone cells such as osteoblasts and compared to other tissues.  It is hypothesized to be acting as an exporter for metabolites from lysosomes, the supposed “waste bag” of the cell.

I will study the localization of the protein in osteoclasts ex vivo (using microscopical methods) and examine its function in vivo using an osteoclast-specific Mfsd1 knock-out mouse. This conditional knockout will be generated by crossing the mouse strain with floxed Mfsd1 alleles with a strain that expresses Cre recombinase under the control of the CathepsinK promoter, a promoter that is highly active in osteoclasts.

Because of the similarities between the limiting membrane of the lysosome and the ruffled border of the osteoclast, we hypothesize that Mfsd1 may be localized at the ruffled border where it may play a role in uptake of bone resorption products.

Postal address:
Biochemisches Institut
Christian-Albrechts-Universität Kiel
Otto-Hahn-Platz 9
D-24118 Kiel

Left to right: Paul Saftig, David Massa and Markus Damme

Left to right: Paul Saftig, David Massa and Markus Damme