PROTEIN KINASE C ISOTYPES IN LEUKEMIA CELL GROWTH

Project: Research project

Description

Protein kinase C (PKC) is an integral part of a major signal transduction
pathway for external stimuli. PKC has been implicated in the proliferation
and differentiation of both normal and leukemic hematopoietic cells.
Phorbol esters (i.e., PMA), which bind to and activate PKC directly, can
induce terminal differentiation of both promyelocytic leukemia HL-60 and
erythroleukemia K562 cells. In contrast, bryostatin 1 (bryo), a non-
phorbol ester PKC activator, stimulates continued cell division and blocks
the cytostatic effects of PMA in these cell lines. The divergent effects
of PMA and bryo correlate with the differential translocation and
activation of alpha and beta11 PKC in response to PMA and bryo. PMA and
bryo activate both alpha and beta11 PKC, however, bryo but not PMA causes
selective translocation and activation of beta11 PKC at the nucleus. In
the proposed studies the expression, cellular distribution and activation
state of the major PKC isotypes (alpha, beta1, beta11, gamma and epsilon)
will be examined in K562 cells during proliferation and PMA-induced
megakaryocytic differentiation. The role of individual PKC isotypes in
proliferation and differentiation will be probed by assessing the effect of
overexpressing and inhibiting the expression of individual PKC isotypes on
the proliferative and differentiation capacity of K562 cells. The
molecular basis for the selective translocation and activation of beta11
PKC at the nucleus in response to bryo will be assessed by constructing and
expressing alpha/beta11 PKC chimeras in K562 cells. PKC chimeras will be
assayed for translocation and activation phenotype in response to PMA and
bryo in intact cells. Likewise, PKC chimeras will be expressed in the
baculovirus expression system, purified from Sf9 insect cells and
characterized for co-factor requirements, activator responsiveness and
substrate specificity in-vitro. The aims of this proposal will be achieved
using a combination of biochemical, immunological, pharmacological and
molecular biological approaches.
StatusFinished
Effective start/end date4/1/922/28/04

Funding

  • National Institutes of Health: $233,248.00
  • National Institutes of Health
  • National Institutes of Health: $99,812.00
  • National Institutes of Health: $177,647.00
  • National Institutes of Health: $34,966.00
  • National Institutes of Health
  • National Institutes of Health: $193,925.00
  • National Institutes of Health: $33,947.00
  • National Institutes of Health: $339,747.00
  • National Institutes of Health: $32,957.00
  • National Institutes of Health
  • National Institutes of Health: $226,750.00
  • National Institutes of Health
  • National Institutes of Health: $131,012.00
  • National Institutes of Health

Fingerprint

Protein Kinase C beta
Protein Kinase C
K562 Cells
Leukemia
Cell Physiological Phenomena
Tetradecanoylphorbol Acetate
Cell Proliferation
Protein Kinase C-alpha
Cytostatic Agents
Leukemia, Erythroblastic, Acute
Growth
Enzymes
Organism Cloning
Cell Differentiation
Signal Transduction
Therapeutics
Paclitaxel
protein kinase C zeta
Proteins

ASJC

  • Medicine(all)