Tyrosyl phosphorylation and activation of the myelin basic protein kinase p44mpk during sea star oocyte maturation

Sanghera, J. S., McNabb, C. K., Tonks, N., Pelech, S. L. (October 1991) Tyrosyl phosphorylation and activation of the myelin basic protein kinase p44mpk during sea star oocyte maturation. Biochimica Et Biophysica Acta, 1095 (2). pp. 153-160. ISSN 0006-3002

URL: http://www.ncbi.nlm.nih.gov/pubmed/1718436
DOI: 10.1016/0167-4889(91)90078-c

Abstract

The most prominent tyrosyl-phosphorylated protein in maturing sea star oocytes was identified as the 44 kDa myelin basic protein (MBP) kinase p44mpk. Immunoblotting studies with anti-phosphotyrosine PY-20 antibody and phosphoamino acid analysis of in vivo [P-32]phosphate-labelled p44mpk showed that the tyrosyl phosphorylation of the kinase correlated with a greater than 10-fold stimulation of its MBP phosphotransferase activity. The activation of p44mpk was reversed almost completely by purified preparations of the protein-tyrosyl phosphatases CD45 and 1B. Purified p44mpk has previously been shown to undergo autophosphorylation in vitro on seryl residues and this was associated with further enhancement of its MBP phosphorylating activity (Sanghera et al. (1991) J. Biol. Chem. 266, 6700-6707). p44mpk also underwent seryl phosphorylation during oocyte maturation, and the protein-seryl/threonyl phosphatase 2A reversed partially the maturation-associated stimulation of its MBP kinase activity. The properties of p44mpk resemble the murine 42 kDa mitogen-activated protein kinase (p42mapk). While p44mpk may feature the phosphorylatable tyrosyl residue that is critical for activation in p42mapk, it lacks the upstream threonyl phosphorylation site that is also required for p42mapk activity (Payne et al. (1991) EMBO J. 10, 885-892). These findings indicate partial differences in the regulatory mechanisms that govern the activities of these isozymes.

Item Type: Paper
Uncontrolled Keywords: MYELIN BASIC PROTEIN KINASE P44MPK KINASE OOCYTE MATURATION CELL-CYCLE CONTROL XENOPUS OOCYTES KINASE PHOSPHATASE-2A PURIFICATION DIVISION
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > myelin basic protein
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression > phosphorylation
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
CSHL Authors:
Communities: CSHL labs > Tonks lab
Depositing User: Matt Covey
Date: October 1991
Date Deposited: 17 Dec 2013 15:38
Last Modified: 17 Dec 2013 15:38
Related URLs:
URI: http://repository.cshl.edu/id/eprint/29091

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