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Smooth muscle sarcolemma‐associated phospholipase C‐β 2 ; agonist‐evoked translocation
Author(s) -
Coburn Ronald F.,
Labelle Edward F.,
Griffiths Thomas,
Baron Carl B.
Publication year - 1997
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199706)171:3<271::aid-jcp5>3.0.co;2-l
Subject(s) - sarcolemma , chromosomal translocation , agonist , microbiology and biotechnology , chemistry , myocyte , biophysics , receptor , biology , biochemistry , gene
About 25% of the total cellular PLCβ 2 content was found to be associated with a sarcolemmal fraction (SARC) isolated from unstimulated porcine trachealis smooth muscle. SARC‐associated PLCβ 2 was located within two compartments, a detergent‐extractable compartment and a nondetergent extractable compartment. SARC PLCβ 2 was measured after extraction with 0.6 M KCl; therefore, PLCβ 2 was not bound solely by electrostatic forces within either of these compartments. PLCβ 2 was shown to translocate from cytosol to SARC during a 20‐sec activation of intact muscle with a muscarinic agonist, carbachol (CARB); i.e., cytosolic total PLCβ 2 content decreased significantly to 73 ± 7% of control and SARC total PLCβ 2 content increased to 180 ± 15% of control value. This translocation was maintained at 5 min of CARB. CARB‐evoked translocation occurred into the detergent‐extractable SARC fraction, and PLCβ 2 content in this fraction increased 300% compared with that in unstimulated muscle. After CARB, SARC PLCβ 2 content accounted for >50% of total cellular PLCβ 2 content. CARB‐evoked increase in PLC activity in SARC paralleled the increase in PLCβ 2 content. CARB‐induced translocations of PLCβ 2 from the cytosol to SARC were of a similar magnitude as occurred with phorbol ester‐induced translocations of PKCα. J. Cell. Physiol. 171:271–283, 1997. © 1997 Wiley‐Liss, Inc.