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Phosphorylation of microtubule‐associated proteins from the ovaries of hemipteran insects by MPF and MAP kinase: Possible roles in the regulation of microtubules during oogenesis
Author(s) -
Lane Jon D.,
Stebbings Howard
Publication year - 1998
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/(sici)1520-6327(1998)39:2<81::aid-arch4>3.0.co;2-r
Subject(s) - microtubule , biology , microbiology and biotechnology , kinase , phosphorylation , protein kinase a , maturation promoting factor , tubulin , oocyte , oogenesis , microtubule associated protein , metaphase , cyclin dependent kinase 1 , biochemistry , cell cycle , cell , embryo , gene , chromosome
Abstract Nutritive tubes that link the developing oocytes to the nurse cells in ovarioles of hemipteran insects contain extensive arrays of microtubules. These are established, then later depolymerised, by developmentally regulated processes. Breakdown of the microtubules corresponds with the activation of M‐phase promoting factor (MPF) and mitogen‐activated protein kinase (MAP kinase), late in oogenesis, as the oocytes proceed to arrest at the first meiotic metaphase [Lane and Stebbings, Roux's Arch Dev Biol 205: 150–159 (1995)]. The mechanisms that lead to the breakdown of nutritive tube microtubules are unknown. Here, we have investigated the possibility that the insect ovarian microtubules are regulated by MPF‐ or MAP kinase‐dependent phosphorylation, focusing upon the prominent high molecular weight microtubule‐associated protein (HMW MAP) enriched in this system, which is a potential target for protein kinase activity in vivo. We have purified the prominent HMW MAPs from the ovaries of two species of hemipterans, and have shown them to be substrates in vitro for the activities of MPF and MAP kinase. However, although the catalytic component of MPF (p34 cdc2 ) is present within microtubule‐rich portions of hemipteran ovarioles, we have found that neither this protein nor its regulatory partner (cyclin B) co‐purify with microtubules during taxol‐mediated microtubule isolation. Arch. Insect Biochem. Physiol. 39:81–90, 1998.© 1998 Wiley‐Liss, Inc.