350
N. K. KARAMANOS
for migration of cells, act as growth factor receptors and their HS chains interact
with various growth factors via specific domains (David 1993). Human immunodeficiency type 2 viruses, for example, bind selectively to HS chains of syndecans
and in this way increase their effectiveness in infectivity. This PG family is considered as the bridge between the extracellular matrix (cell-cell and cell-matrix
interactions) and the cell signal transduction pathways.
Perlecan, is a HSPG and constitutes a major structural component of the basement membrane. The negative charges of HS provide the basement membranes
with a negative surface that acts either as antithrombogenic factor or as selective
filter in the kidney.
Serglycin, the PG found in storage granules of mast cells contains a large number of heparin or oversulfated CS chains with high molecular size. The GAG
chains are concentrated into a short protein core region that contains serineglycine repeats. Serglycin is, therefore, a compact PG with very high negative
charge density, able to bind and concentrate cationic histamines, proteases and
glucosaminidases. The bound constituents are released when mast cells degranulate in host defense responses. The other small PGs decorin, biglycan, fibromodulin, as well as the KSPG found in cornea (lumican), are of importance in the
network organization since they interact with collagen fibrils in most connective
tissues (Hardingham and Fosang 1992).
Hyaluronan is a ubiquitous GAG with a wide variety of functions. This GAG
forms the ligand structure for a family of aggregating proteins, the hyaladherins
(Prehm 1984). Through such bindings, HA, for example, can form huge complexes with PGs of the ECM and it can participate in the aggregation of lymphocytes. HA also plays important roles in tissue morphogenesis, in angiogenesis
and in tissue remodeling. Because of the universal presence of this molecule,
attempts have also been made to analyze HA for diagnostic purposes (Nurminen
et al. 1994, Karamanos and Hjerpe 1997, Lamari et al. 1998). High levels of this
GAG in a pleural effusion seem to be pathognomonic for a malignant mesothelioma, but serum levels are also affected in rheumatoid conditions, in liver diseases
and in malignancies (Cooper and Rathbone 1990). HA is now widely used pharmaceutically to relieve pain in osteoarthrosis and medico-technically in eye surgery.
4
Labelling, Isolation and Characterization of PGs
The steps we have to follow for studying PGs involve their labelling, extraction/
solubilization, fractionation and characterization of their type. Although there
are some definite procedures when studying PGs it should be noted that due to
the structural heterogeneity of PGs these procedures may be modified for solving
particular problems. Commonly used strategies are discussed below. For more
details on the labelling and fractionation of PGs the excellent review of Hascall et
al. 1994 is proposed.
N. K. KARAMANOS
for migration of cells, act as growth factor receptors and their HS chains interact
with various growth factors via specific domains (David 1993). Human immunodeficiency type 2 viruses, for example, bind selectively to HS chains of syndecans
and in this way increase their effectiveness in infectivity. This PG family is considered as the bridge between the extracellular matrix (cell-cell and cell-matrix
interactions) and the cell signal transduction pathways.
Perlecan, is a HSPG and constitutes a major structural component of the basement membrane. The negative charges of HS provide the basement membranes
with a negative surface that acts either as antithrombogenic factor or as selective
filter in the kidney.
Serglycin, the PG found in storage granules of mast cells contains a large number of heparin or oversulfated CS chains with high molecular size. The GAG
chains are concentrated into a short protein core region that contains serineglycine repeats. Serglycin is, therefore, a compact PG with very high negative
charge density, able to bind and concentrate cationic histamines, proteases and
glucosaminidases. The bound constituents are released when mast cells degranulate in host defense responses. The other small PGs decorin, biglycan, fibromodulin, as well as the KSPG found in cornea (lumican), are of importance in the
network organization since they interact with collagen fibrils in most connective
tissues (Hardingham and Fosang 1992).
Hyaluronan is a ubiquitous GAG with a wide variety of functions. This GAG
forms the ligand structure for a family of aggregating proteins, the hyaladherins
(Prehm 1984). Through such bindings, HA, for example, can form huge complexes with PGs of the ECM and it can participate in the aggregation of lymphocytes. HA also plays important roles in tissue morphogenesis, in angiogenesis
and in tissue remodeling. Because of the universal presence of this molecule,
attempts have also been made to analyze HA for diagnostic purposes (Nurminen
et al. 1994, Karamanos and Hjerpe 1997, Lamari et al. 1998). High levels of this
GAG in a pleural effusion seem to be pathognomonic for a malignant mesothelioma, but serum levels are also affected in rheumatoid conditions, in liver diseases
and in malignancies (Cooper and Rathbone 1990). HA is now widely used pharmaceutically to relieve pain in osteoarthrosis and medico-technically in eye surgery.
4
Labelling, Isolation and Characterization of PGs
The steps we have to follow for studying PGs involve their labelling, extraction/
solubilization, fractionation and characterization of their type. Although there
are some definite procedures when studying PGs it should be noted that due to
the structural heterogeneity of PGs these procedures may be modified for solving
particular problems. Commonly used strategies are discussed below. For more
details on the labelling and fractionation of PGs the excellent review of Hascall et
al. 1994 is proposed.