title: Immunohistochemical identification and fiber type specific localization of protein kinase C isoforms in equine skeletal muscle.
abstract: OBJECTIVE
  To investigate whether protein kinase C (PKC) isoforms are expressed in equine skeletal muscle and determine their distribution in various types of fibers by use of immunofluorescence microscopy.
  
  
  METHODS
  5 healthy adult Dutch Warmblood horses.
  
  
  METHODS
  In each horse, 2 biopsy specimens were obtained from the vastus lateralis muscle. Cryosections of equine muscle were stained with PKC isoform (alpha, beta1, beta2, delta, epsilon, or zeta)-specific polyclonal antibodies and examined by use of a fluorescence microscope. Homogenized muscle samples were evaluated via western blot analysis.
  
  
  RESULTS
  The PKC alpha, beta1, beta2, delta, epsilon, and zeta isoforms were localized within the fibers of equine skeletal muscle. In addition, PKC alpha and beta2 were detected near or in the plasma membrane of muscle cells. For some PKC isoforms, distribution was specific for fiber type. Staining of cell membranes for PKC alpha was observed predominantly in fibers that reacted positively with myosin heavy chain (MHC)-IIa; PKC delta and epsilon staining were more pronounced in MHC-I-positive fibers. In contrast, MHC-I negative fibers contained more PKC zeta than MHC-I-positive fibers. Distribution of PKC beta1 was equal among the different fiber types.
  
  
  CONCLUSIONS
  Results indicated that PKC isoforms are expressed in equine skeletal muscle in a fiber type-specific manner. Therefore, the involvement of PKC isoforms in signal transduction in equine skeletal muscle might be dependent on fiber type.
authors.affiliation: Department of Equine Sciences, Discipline of Internal Medicine, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
authors.forename: Mireille M E
authors.initials: MM
authors.lastname: van Ginneken
authors.forename: Hans A
authors.initials: HA
authors.lastname: Keizer
authors.forename: Inge D
authors.initials: ID
authors.lastname: Wijnberg
authors.forename: Klien G
authors.initials: KG
authors.lastname: van Dam
authors.forename: Gert
authors.initials: G
authors.lastname: Schaart
authors.forename: Ellen
authors.initials: E
authors.lastname: de Graaf-Roelfsema
authors.forename: Johannes H
authors.initials: JH
authors.lastname: van der Kolk
authors.forename: Eric
authors.initials: E
authors.lastname: van Breda
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006736:Horses / Q000378:metabolism*; D007527:Isoenzymes / Q000032:analysis; D008856:Microscopy, Fluorescence; D018485:Muscle Fibers, Skeletal / Q000201:enzymology*; D018482:Muscle, Skeletal / Q000201:enzymology*; D011493:Protein Kinase C / Q000032:analysis*; D015398:Signal Transduction
chemical_list: D007527:Isoenzymes; D011493:Protein Kinase C