Expression and function of C1q receptors and C1q binding proteins at the cell surface.
C1q is the recognition unit of the first component of complement that binds not only IgG and IgM containing immune complexes, but also recognizes foreign structures such as the lipid A of endotoxin, and molecules expressed at the surface of apoptotic cells. In this review, the plasma membrane receptors and binding proteins for C1q are discussed and new data are presented on calreticulin expression on human peripheral blood cells. Although much is known about C1q receptors and binding molecules there are still many questions regarding their role in vivo.
Ghiran
Ionita
I
Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Tyagi
Shiv-Raj
SR
Klickstein
Lloyd B
LB
Nicholson-Weller
Anne
A
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001773:Blood Cells / Q000502:physiology; D037282:Calreticulin / Q000378:metabolism; D002352:Carrier Proteins; D002462:Cell Membrane / Q000378:metabolism; D015922:Complement C1q / Q000737:chemistry / Q000378:metabolism*; D003171:Complement Pathway, Classical / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D018960:Hyaluronan Receptors; D008562:Membrane Glycoproteins; D024101:Mitochondrial Proteins; D011951:Receptors, Complement / Q000737:chemistry / Q000378:metabolism*; D017463:Receptors, Complement 3b / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism
D015703:Antigens, CD; C087299:C1QBP protein, human; D037282:Calreticulin; D002352:Carrier Proteins; D018960:Hyaluronan Receptors; D008562:Membrane Glycoproteins; D024101:Mitochondrial Proteins; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D012795:Sialoglycoproteins; C032402:complement 1q receptor; D015922:Complement C1q