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Characterization of mammalian heart annexins with special reference to CaBP33 (annexin V)
Author(s) -
Pula Grazia,
Bianchi Roberta,
Ceccarelli Paolo,
Giambanco Ileana,
Donato Rosario
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80808-v
Subject(s) - annexin , chemistry , annexin a2 , medicine , microbiology and biotechnology , biochemistry , biology , apoptosis
Porcine heart was observed to express annexins V (CaBP33) and VI in large amounts, and annexins III and IV in much smaller amounts. Annexin V (CaBP33) in porcine heart was examined in detail by immunochemistry. Homogenization and further processing of heart in the presence of EGTA resulted in the recovery of annexin V (CaBP33) in the cytosolic fraction and in an EGTA‐resistant, Triton X‐100‐soluble fraction from cardiac membranes. Including Ca 2+ in the homogenization medium resulted in a significant decrease in the annexin V (CaBP33) content of the cytosolic fraction with concomitant increase in the content of this protein in myofibrils, mitochrondria, the sarcoplasmic reticulum and the sarcolemma. The amount of annexin V (CaBP33) in each of these subfractions depended on the free Ca 2+ concentration in the homogenizing medium. At the lowest free Ca 2+ concentration tested, 0.8 μM, only the sarcolemma appeared to contain bound annexin V (CaBP33). Membrane‐bound annexins V (CaBP33) and VI partitioned in two fractions, one EGTA‐resistant and Triton X‐100‐extractable, and one Triton X‐100‐resistant and EGTA‐extractable. Altogether, these data suggest that annexins V and VI are involved in the regulation of membrane‐related processes.