Carbonic anhydrase XIV in skeletal muscle: subcellular localization and function from wild-type and knockout mice.
The expression of carbonic anhydrase (CA) XIV was investigated in mouse skeletal muscles. Sarcoplasmic reticulum (SR) and sarcolemmal (SL) membrane fractions were isolated from wild-type (WT) and CA XIV knockout (KO) mice. The CA XIV protein of 54 kDa was present in SR and SL membrane fractions as shown by Western blot analysis. CA activity measurements of WT and KO membrane fractions showed that CA XIV accounts for approximately 50% and 66% of the total CA activities determined in the SR and SL fractions, respectively. This indicates the presence of at least one other membrane-associated CA isoform in these membranes, e.g., CA IV, CA IX, or CA XII. Muscle fibers of the extensor digitorum longus (EDL) muscle were immunostained with anti-CA XIV/FITC and anti-sarco(endo)plasmic reticulum Ca(2+)-ATPase 1/TRITC, with anti-CA XIV/FITC and anti-ryanodine receptor/TRITC, or with anti-CA XIV/FITC and anti-monocarboxylate transporter-4/TRITC. CA XIV was expressed in the plasma membrane and in the longitudinal SR but not in the terminal SR. Isometric contraction measurements of single twitches and tetani and a fatigue protocol applied to fiber bundles of the fast-twitch EDL and of the slow-twitch soleus muscle from WT and KO mice showed that the lack of SR membrane-associated CA XIV did not affect maximum force, rise and relaxation times, and fatigue behavior. Thus, it is concluded that a reduction of the total SR CA activity by approximately 50% in CA XIV KO mice does not lead to an impairment of SR function.
Wetzel
Petra
P
Zentrum Physiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany. wetzel.petra@mh-hannover.de
Scheibe
Renate J
RJ
Hellmann
Bernd
B
Hallerdei
Janine
J
Shah
Gul N
GN
Waheed
Abdul
A
Gros
Gerolf
G
Sly
William S
WS
D000136:Acid-Base Equilibrium; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D007537:Isometric Contraction; D051379:Mice; D018345:Mice, Knockout; D027501:Monocarboxylic Acid Transporters / Q000032:analysis; D018763:Muscle Fatigue; D018485:Muscle Fibers, Skeletal / Q000737:chemistry / Q000201:enzymology*; D009124:Muscle Proteins / Q000032:analysis; D009126:Muscle Relaxation; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D011499:Protein Processing, Post-Translational; D019837:Ryanodine Receptor Calcium Release Channel / Q000032:analysis; D012508:Sarcolemma / Q000201:enzymology; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
C506944:Atp2a1 protein, mouse; D027501:Monocarboxylic Acid Transporters; D009124:Muscle Proteins; D019837:Ryanodine Receptor Calcium Release Channel; C498648:Slc16a4 protein, mouse; D017301:Ca(2+) Mg(2+)-ATPase; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002256:Carbonic Anhydrases; C466621:carbonic anhydrase XIV; D000254:Sodium-Potassium-Exchanging ATPase