TY - JOUR
T1 - Fibroblast contractility without an increase in basal myosin light chain phosphorylation in wild type cells and cells expressing the catalytic domain of myosin light chain kinase
AU - Obara, K.
AU - Nikcevic, G.
AU - Pestic, L.
AU - Nowak, G.
AU - Lorimer, D. D.
AU - Guerriero, V.
AU - Elson, E. L.
AU - Paul, R. J.
AU - De Lanerolle, P.
PY - 1995/8/11
Y1 - 1995/8/11
N2 - We investigated the role of myosin light chain (MLC20) phosphorylation (MLC-P) in non-muscle contractility by comparing MLC-P and the contractile properties of wild type 3T3 fibroblasts and 3T3 fibroblasts expressing the catalytic domain of myosin light chain kinase (tMK), MLC-P is 0.96 mol of PO4/mol of MLC20 in cells expressing tMK compared to 0.20 mol of PO4/mol of MLC20 in control cells. Expressing tMK also results in a 2-fold increase in cortical stiffness compared to control cells. Contractile properties were quantified by growing wild type and transfected fibroblasts in collagen and attaching the ensuing fibers to an apparatus for performing mechanical measurements. Serum stimulation resulted in a dose-dependent increase in force with maximal force generated in the presence of 30% (v/v) serum. Surprisingly, MLC-P did not increase in wild type cells following stimulation with 30% serum, and tMK expression did not affect the contractile properties of fibers made from these cells. Moreover, the dose responses to serum, maximal force, force-velocity relationships, and dynamic stiffness were similar in the wild type cells and fibroblasts expressing tMK. These data demonstrate that non-muscle cells can generate force without an increase in MLC-P, and that an increase in MLC-P does not affect the contractile properties of fibroblast fibers.
AB - We investigated the role of myosin light chain (MLC20) phosphorylation (MLC-P) in non-muscle contractility by comparing MLC-P and the contractile properties of wild type 3T3 fibroblasts and 3T3 fibroblasts expressing the catalytic domain of myosin light chain kinase (tMK), MLC-P is 0.96 mol of PO4/mol of MLC20 in cells expressing tMK compared to 0.20 mol of PO4/mol of MLC20 in control cells. Expressing tMK also results in a 2-fold increase in cortical stiffness compared to control cells. Contractile properties were quantified by growing wild type and transfected fibroblasts in collagen and attaching the ensuing fibers to an apparatus for performing mechanical measurements. Serum stimulation resulted in a dose-dependent increase in force with maximal force generated in the presence of 30% (v/v) serum. Surprisingly, MLC-P did not increase in wild type cells following stimulation with 30% serum, and tMK expression did not affect the contractile properties of fibers made from these cells. Moreover, the dose responses to serum, maximal force, force-velocity relationships, and dynamic stiffness were similar in the wild type cells and fibroblasts expressing tMK. These data demonstrate that non-muscle cells can generate force without an increase in MLC-P, and that an increase in MLC-P does not affect the contractile properties of fibroblast fibers.
UR - http://www.scopus.com/inward/record.url?scp=0029099125&partnerID=8YFLogxK
U2 - 10.1074/jbc.270.32.18734
DO - 10.1074/jbc.270.32.18734
M3 - Article
C2 - 7642521
AN - SCOPUS:0029099125
SN - 0021-9258
VL - 270
SP - 18734
EP - 18737
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 32
ER -