Related Experiment Video
Updated: Feb 22, 2026
Blood Collection from the American Horseshoe Crab, Limulus Polyphemus
Published on: October 13, 2008
Clotting protein - An extracellular matrix (ECM) protein involved in crustacean hematopoiesis
Kingkamon Junkunlo1, Kenneth Söderhäll1, Irene Söderhäll1
1Department of Comparative Physiology, Uppsala University, Norbyvägen 18A, 752 36 Uppsala, Sweden.
Hematopoietic progenitor cells in crustaceans are organized in lobule-like structures surrounded by different types of cells and extracellular matrix (ECM) proteins in a Hematopoietic tissue (HPT). Here we show that the clotting protein (CP) is part of the ECM in HPT and is secreted during HPT cell culture. The formation of a filamentous network of CP was observed in HPT cell culture. A high amount of CP protein was detected at the surfaces of undifferentiated cells (round-shaped) compared with migrating cells (spindle shaped). Co-localization of the CP protein and TGase activity was observed on the cell surface and filamentous network between cells. A role for CP together with collagen was revealed in a 3D culture in which a collagen-I matrix was immobilized with CP or supplemented with CP. The results showed possible functions of CP, collagen, TGase and the cytokine Ast1 in the regulation of HPT progenitor cell behavior. This is the first study to provide insight into the role of CP, which probably not only participates in clot formation but also functions as an ECM component protein controlling hematopoietic stem cell behavior.
Hematopoietic progenitor cells in crustaceans are organized in lobule-like structures surrounded by different types of cells and extracellular matrix (ECM) proteins in a Hematopoietic tissue (HPT). Here we show that the clotting protein (CP) is part of the ECM in HPT and is secreted during HPT cell culture. The formation of a filamentous network of CP was observed in HPT cell culture. A high amount of CP protein was detected at the surfaces of undifferentiated cells (round-shaped) compared with migrating cells (spindle shaped). Co-localization of the CP protein and TGase activity was observed on the cell surface and filamentous network between cells. A role for CP together with collagen was revealed in a 3D culture in which a collagen-I matrix was immobilized with CP or supplemented with CP. The results showed possible functions of CP, collagen, TGase and the cytokine Ast1 in the regulation of HPT progenitor cell behavior. This is the first study to provide insight into the role of CP, which probably not only participates in clot formation but also functions as an ECM component protein controlling hematopoietic stem cell behavior.
Related Concept Videos
01:09Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
01:06Coagulation
01:20Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
01:16Clot Retraction and Fibrinolysis
01:22Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
01:18Structure and Function of Platelets
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...