MOLECULAR CONTROL OF INTRACELLULAR CA++ RELEASE PATTERNS

Project: Research project

Project Details

Description

Recent developments in the application of confocal microscopy to the
study of intracellular Ca2+ imaging have demonstrated the existence of
complex patterns of intracellular Ca2+ release generated in Xenopus
oocytes by the activation of hormone receptor pathways. In particular,
the patterns of Ca2+ foci and spiral waves of Ca2+ observed, behaved in
a fashion consistent with the notion that intracellular Ca2+ release is
an excitable process. Studying these patterns will generate information
about the underlying cellular machinery which contributes to Ca2+
signalling. The relevance of the proposed studies to the field of Ca2+
signalling lies in the fact that with great spatial and temporal
resolution one can study discrete entities (i.e. Ca2+ foci and/or spiral
Ca2+ waves) which fill a gap in the understanding of the steps that
follow hormone receptor activation to Ca2+ sensitive effectors downstream
in the cascade of cellular signal events. Precise knowledge of when and
where intracellular cellular Ca2+ is mobilized is relevant to all
enzymatic processes which use Ca2+ as their messenger (e.g. Ca2+ -
dependent kinases, phosphatases, proteases). This proposal presents
evidence that the production of inositol trisphosphate (IP3), the
activation of the IP3 receptor (IP3R) and Ca2+ itself, are critical to
the formation of Ca2+ release patterns. A multidisciplinary approach
which uses techniques of molecular biology, confocal imaging, and
electrophysiology is proposed. Simultaneous confocal Ca2+ imaging and
immunofluorescence will be used to determine the distribution of Ca2+
activity patterns in relation to the localization of the IP3R and to the
Ca2+ -ATPases of the endoplasmic reticulum (ER). Ca2+ pattern formation
will be studied by manipulating the expression levels of the IP3R, over-
expressing Ca2+ -ATPases to manipulate the size of the Ca2+ stores, and
by manipulating the production of IP3 by expression of different hormonal
receptor pathways. These components of the system are more likely to have
an impact in the formation of Ca2+ patterns. The Xenopus oocyte
translation system has been chosen because of the ease with which foreign
cDNAs are introduced and expressed, and because confocal Ca2+ imaging in
these preparation has yielded excellent temporal and spatial resolution
in the imaging of Ca2+ patterns.
StatusFinished
Effective start/end date1/1/937/31/07

Funding

  • National Institutes of Health: $65,250.00
  • National Institutes of Health: $251,234.00
  • National Institutes of Health: $183,116.00
  • National Institutes of Health: $302,246.00
  • National Institutes of Health: $309,520.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $309,520.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health: $244,002.00
  • National Institutes of Health: $309,520.00
  • National Institutes of Health: $171,273.00
  • National Institutes of Health: $258,684.00

ASJC

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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