Detail of "99896-85-2"

Reference

Isolation and characterization of a chymotryptic fragment of platelet glycoprotein IIb-IIIa retaining Arg-Gly-Asp binding activity

Isolation and characterization of a chymotryptic fragment of platelet glycoprotein IIb-IIIa retaining Arg-Gly-Asp binding activity. Lam, Stephen C.Several substances are used for example 99896-85-2 which is its cas registry number. T. (Dep. Pharmacol., Univ. Illinois, Chicago, IL 60612, USA). J. Biol. Chem., 267(8), 5649-55 (English) 1992. CODEN: JBCHA3. ISSN: 0021-9258. DOCUMENT TYPE: Journal CA Section: 6 (General Biochemistry) Section cross-reference(s): 13 Platelet membrane glycoprotein (GP)IIb-IIIa exists as a divalent cation-dependent heterodimer which recognizes the Arg-Gly-Asp (RGD) sequence of adhesive proteins. To isolate the RGD binding domain of GPIIb-IIIa proteolysis of GPIIb-IIIa was performed with a-chymotrypsin. GPIIb-IIIa was bound to an affinity matrix of GRGDSPK-coupled Sepharose 4B and was then treated with chymotrypsin. After washing the unbound fragments, two discrete polypeptides of 55 and 85 kDa remained bound to the RGD affinity matrix and were specifically eluted by sol. HHLGGAKQAGDV (H12) or by GRGDSP, but not by GRGESP. Immunoblotting with subunit-specific polyclonal antibodies showed that the 55- and 85-kDa fragments were derived from GPIIb and GPIIIa, resp. Amino-terminal sequencing and immunoblotting using site-specific antibodies indicated that these fragments contained the amino termini of their parent mols. In the presence of 1 mM Ca2+ and 1 mM Mg2+, these two fragments were maintained as a heterodimer inasmuch as both fragments were immunopptd. by the polyclonal anti-GPIIIa antibodies. In contrast, chelating the divalent cations with 5 mM EDTA resulted in the lack of coimmunopptn. of the 55-kDa GPIIb fragment. After removal of the H12 peptide, the 55/85-kDa heterodimer bound to immobilized fibrinogen in an ELISA by an RGD-dependent mechanism. These findings suggest that the RGD binding domain and structures required for heterodimer maintenance are present within the 55/85-kDa chymotryptic fragment of GPIIb-IIIa. .

Arg-Gly-Asp-containing peptides expose novel collagen receptors on fibroblasts: implications for wound healing

Arg-Gly-Asp-containing peptides expose novel collagen receptors on fibroblasts: implications for wound healing. Agrez, Michael V.; Bates, Richard C.; Boyd, Andrew W.; Burns, Gordon F. (Fac. Med., Univ. Newcastle, Newcastle, Australia). Cell Regul., 2(12), 1035-44 (English) 1991. CODEN: CELREQ. ISSN: 1044-2030. DOCUMENT TYPE: Journal CA Section: 14 (Mammalian Pathological Biochemistry) Section cross-reference(s): 13 Integrins are a family of cell-surface receptors intimately involved in the interactions of cells with their extracellular matrix. These receptors comprise an a and b subunit in noncovalent assocn. and many have been shown to recognize and bind an arginine-glycine-aspartate (RGD) sequence contained within their specific extracellular matrix ligand. Fibroblasts express integrin receptors belonging to two major subfamilies. Some of the members within the subfamily defined by b1 (VLA) are receptors for collagen but, perhaps surprisingly, the other major subfamily of integrins on fibroblasts (that defined by the a chain of the vitronectin receptor, av) all appear to bind primarily vitronectin and/or fibronectin. The present study shows that RGD-contg. peptides expose cryptic binding sites on the av-assocd. integrins enabling them to function as collagen receptors. The addn. of RGD-contg. peptides to fibroblasts cultured on type I collagen induced dramatic cell elongation and, when the cells were contained within collagen matrixes, the peptides induced marked contraction of the gels. These processes were inhibited by Fab fragments of a monoclonal antibody against an av integrin.There are some commonly used reagents with their cas registry numbers 93674-97-6 and 99896-85-2 in this article. Also, av-assocd. integrins from cell lysates bound to collagen I affinity columns in the presence, but not in the absence, of RGD-contg. peptides. These data suggest a novel regulatory control for integrin function. In addn., because the cryptic collagen receptors were shown to be implicated in the contraction of collagen gels, the generation of such binding forces suggests that this may be the major biol. role for these integrins in processes such as wound healing. .