220- and 130-kDa MLCKs have distinct tissue distributions and intracellular localization patterns.
To better understand the distinct functional roles of the 220- and 130-kDa forms of myosin light chain kinase (MLCK), expression and intracellular localization were determined during development and in adult mouse tissues. Northern blot, Western blot, and histochemical studies show that the 220-kDa MLCK is widely expressed during development as well as in several adult smooth muscle and nonmuscle tissues. The 130-kDa MLCK is highly expressed in all adult tissues examined and is also detectable during embryonic development. Colocalization studies examining the distribution of 130- and 220-kDa mouse MLCKs revealed that the 130-kDa MLCK colocalizes with nonmuscle myosin IIA but not with myosin IIB or F-actin. In contrast, the 220-kDa MLCK did not colocalize with either nonmuscle myosin II isoform but instead colocalizes with thick interconnected bundles of F-actin. These results suggest that in vivo, the physiological functions of the 220- and 130-kDa MLCKs are likely to be regulated by their intracellular trafficking and distribution.
Blue
Emily K
EK
Department of Cellular and Integrative Physiology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
Goeckeler
Zoe M
ZM
Jin
Yijun
Y
Hou
Ling
L
Dixon
Shelley A
SA
Herring
B Paul
BP
Wysolmerski
Robert B
RB
Gallagher
Patricia J
PJ
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004622:Embryo, Mammalian / Q000201:enzymology; D005314:Embryonic and Fetal Development; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000201:enzymology; D009219:Myosin-Light-Chain Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D009928:Organ Specificity; D020033:Protein Isoforms; D016415:Sequence Alignment; D014018:Tissue Distribution
D000199:Actins; D020033:Protein Isoforms; D009219:Myosin-Light-Chain Kinase; D009218:Myosins