AlphaB-crystallin in the rat lens is phosphorylated at an early post-natal age.
We determined the developmental changes in the phosphorylation state of alphaB-crystallin in lenses from rats at various post-natal ages by isoelectric focusing gel electrophoresis or sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a subsequent Western blot analysis of extracts of lenses using antibodies that recognized the carboxy-terminal sequence or each of the three phosphorylated serine residues (Ser-19, Ser-45 and Ser-59) in alphaB-crystallin. Phosphorylated forms of alphaB-crystallin were barely detected at birth but they became detectable at 3 weeks of age and reached plateau levels at 8 weeks of age. The phosphorylation of alphaB-crystallin at Ser-45 was observed preferentially. The active form of p44/42 MAP kinase, which is responsible for the phosphorylation of Ser-45 in alphaB-crystallin, also increased in a development-dependent manner. Thus we found that the developmental increase of the phosphorylation at Ser-45 of alphaB-crystallin in the rat lens was due to the developmental activation of p44/42 MAP kinase.
Ito
H
H
Department of Biochemistry, Institute for Developmental Research, Aichi Human Service Center, Kasugai, Japan. itohide@inst-hsc.pref.aichi.jp
Iida
K
K
Kamei
K
K
Iwamoto
I
I
Inaguma
Y
Y
Kato
K
K
D000818:Animals; D000831:Animals, Newborn; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D003459:Crystallins / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D007908:Lens, Crystalline / Q000378:metabolism*; D008297:Male; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
D003459:Crystallins; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases