Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016632 (Fox)
 1,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Calpain is distributed ubiquitously in virtually every tissue (Croall, D. E., and DeMartino, G. N. (1991) Physiol. Rev. 71, 813-846), but its physiological role remains to be determined. The identification of its natural endogenous substrates would be of great interest. Since pp60src, a major tyrosine kinase in platelets, is known to be easily cleaved during purification from cells (Feder, D., and Bishop, J. M. (1990) J. Biol. Chem. 265, 8205-8211), we examined the possibility that it is an endogenous substrate of calpain. In the whole cell lysate from resting platelets, which was analyzed by Western blotting with monoclonal antibody 327, we found pp60src almost exclusively in a 60-kDa form, with a trace of 52-kDa form. Addition of A23187 (a calcium ionophore) or dibucaine, which are known to be activators of platelet calpain (Croall and DeMartino, 1991; Fox, J. E., Reynolds, C., Morrow, J. S., and Phillips, D. R. (1987) Blood 76, 2510-2519; Fox, J. E., Austin, C. D., Boyles, J. K., and Steffen, P. K. (1990b) J. Cell Biol. 111, 483-493), caused dose- and time-dependent cleavage of actin-binding protein and p235 protein (talin). At the same time, loss of the 60-kDa species of pp60src and generation of the 52-kDa (occasionally seen as doublets) and 47-kDa species were detected by the Western blotting. In platelets aggregated by 1 unit/ml thrombin, apparently identical cleavage products were found. The cleavage of pp60src was inhibited by calpeptin (20 microM), an inhibitor of calpain (Tsujinaka, T., Kajiwara, Y., Kambayashi, J., Sakon, M., Higuchi, N., Tanaka, T., and Mori, T. (1988) Biochem. Biophys. Res. Commun. 153, 1201-1208; Tsujinaka, T., Ariyoshi, H., Uemura, Y., Sakon, M., Kambayashi, J., and Mori, T. (1990) Life Sci. 46, 1059-1066; Fox, J. E., Clifford, C. C., and Austin, C. D. (1990) Blood 76, 2510-2519; Fox, J. E., Austin, C. D., Boyles, J. K., and Steffen, P. K. (1990) J. Cell. Biol. 111, 483-493; Fox, J. E., Austin, C. D., Clifford, C. C., and Steffen, P. K. (1991) J. Biol. Chem. 266, 13289-13295). Addition of EGTA (3 mM) to the extracellular media completely inhibited the cleavage of actin-binding protein, talin, and pp60src in response to A23187 (1 microM). Intact pp60src was distributed in both cytosolic and particulate (membrane) fractions. Cleaved species were found exclusively in the cytosolic fraction. pp60src-associated enolase kinase activity was reduced. Thus, pp60src is an endogenous substrate for calpain, the cleavage of which may have regulatory effects on the kinase.
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PMID:pp60src is an endogenous substrate for calpain in human blood platelets. 768 44

1 Ophthalmic manifestations of presumed rifabutin-related uveitis. Arevalo JF, Freeman WR, La Jolla, CA, USA. 2 Diagnosis of toxoplasmosis acute anterior uveitis by PCR. Cano J, Diaz M, Navee A, Maldonado M, Barcelona, Spain. 3 Neuroretinits in patients with AIDS. Berger B, Austin TX, USA. 4 Presumed varicella zoster retinitis in a pediatric patient with AIDS. El Baba F, Nachman S, Stony Brook, NY, USA. 5 ARN with hypopyon caused by EVB and herpes type VI viruses. Cano J, Diaz M, Navea A, Maldonado MJ, Barcelona, Spain. 6 CD8(+) T-lymphocytes and ocular infections in HIV(+) patients. Lowder CY, Butler CP, Dodds EM, Recillas-Gispert C, Cleveland, OH, USA. 7 Intravitreal foscanet for persistent CMV. Lieberman RM, Orellana J, New York, NY, USA. 8 Perfluorocarbon liquid versus air-fluid exchange during surgical repair of retinal detachment caused by cytomegalovirus retinitis in patients with AIDS. Sery T, Gomes J, Sando R, Dua H, Donoso L, Vrabec T, Philadelphia, PA, USA. 9 Endogenous ophthalmitis simulating retinoblastoma: a report of six cases. Shields J, Shields C, Eagle R, Barrett J, DePotter P, Philadelphia, PA, USA. 10 Ocular lymphoma resembling chronic postoperative endophthalmitis. Fox G, Chan CC, Whitcup SM, Nussenblatt R, Bethesda, MD, USA. 11 A phase II trial of combination chemotherapy for primary central nervous system lymphoma. Whitcup SM, Stark-Vanes V, Nussenblatt RB, Heiss H, Witte R, Bethesda, MD, USA. 12 Cancer-induced autoimmune retinopathy. Thirkill C, Sacramento, CA, USA. 13 Leukocytoclastic vasculitis. Tessler H. Chicago, IL, USA. 14 Bilateral choroidal neovascular membranes after Candida albicans chorioretinitis. Dodds E, Townsend-Pico W, Lowder CY, Lewis H, Cleveland, OH, USA. 15 An unusual complications of Toxoplasma retinochoroiditis. Gormley PD, Flaxel CJ, Pavesio CE, Conrad DK, Lightman S, London, UK. 16 Surgical removal of a choroidal neovascular membrane in sympahtetic ophthalmia. Conrad DK, McCluskey PJ, Schwartz S, Gregor Z. Lightman S, London, UK. 17 Peripheral laser scatter ablation in pars planitia. Park SE, Mieler WF, Pulido JS, Milwaukee, WI, USA.
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PMID:American uveitis society meeting october 31, 1994 san francisco, california. 2282 44