Roger Karlsson

Professor Roger Karlsson

Stockholm University
The Wenner-Gren Institute
Cell Biology
Svante Arrheniusväg 20B, room F468/F473
106 91 Stockholm

Phone: 00 46 8 16 41 04
Fax: 00 46 8 15 98 37



The Microfilament system and Profilin: Actin

We study eukaryotic cell behavior with a focus on the organization and regulation of the microfilament system – a force generating machinery of proteins with actin as principal component. As an intimate component of the cell periphery, the microfilament system responds to receptor activation by forming surface-protruding actin containing processes used for substrate adhesions, contacts with other cells and for migration. It mediates intracellular movements of vesicles and macromolecular complexes, and actin and actin-binding proteins also function in different nuclear processes. Profilin is an actin-binding protein which together with the non-muscle actin isoforms has been under our study for nearly three decades. It controls actin polymerization through the docking of profilin:actin complexes to protein machineries like WASP/Wave, Ena/VASP and members of the formin family of proteins. Thus profilin is important for the fine-tuning and regulation in time and space of actin polymerization, for instance during formation of protruding lamellipodia and filopodia at advancing cell edges. Profilin also binds the phosphoinositide lipids PIP2 and PIP3 further emphasizing the close association to plasma membrane associated receptor signaling. The connection of the microfilament system with cell signaling, growth control, adhesion and migration explains why cancer cells often display changes in microfilament organization and actin regulatory components.

Selected publications

Johnsson AK, Karlsson R.
Synaptotagmin 1 causes phosphatidyl inositol lipid-dependent actin remodeling in cultured non-neuronal and neuronal cells.

Exp Cell Res. 2011 Oct 14. [Epub ahead of print]
PMID: 22036579

Lassing I, Hillberg L, Höglund AS, Karlsson R, Schutt C, Lindberg U.
Tropomyosin is a tetramer under physiological salt conditions.
Cytoskeleton (Hoboken). 2010 Sep;67(9):599-607.
PMID: 20658558

Johnsson AK, Karlsson R.
Microtubule-dependent localization of profilin I mRNA to actin polymerization sites in serum-stimulated cells.
Eur J Cell Biol. 2010 May;89(5):394-401. Epub 2010 Feb 2.
PMID: 20129697






Cell Biology  Per Ljungdahl, Phone: +46 8 16 41 01

Developmental Biology Christos Samakovlis, Phone: + 46 8 16 15 64

Immunology Marita Troye Blomberg, Phone: + 46 8 16 41 64

Physiology Barbara Cannon, Phone:+ 46 8 16 41 20


Imaging Facility, IFSU

Zeiss LSM 780