INVESTIGADORES
SCHNITTGER Leonhard
artículos
Título:
Initiation of translation and cellular localization of Theileria annulata casein kinase IIalpha: implication for its role in host cell transformation.
Autor/es:
BIERMANN R, SCHNITTGER L, BEYER D, AHMED JS.
Revista:
JOURNAL OF CELLULAR PHYSIOLOGY
Referencias:
Año: 2003 p. 444 - 453
ISSN:
0021-9541
Resumen:
Theileria annulata and T. parva are protozoa that infect bovine
leukocytes which leads to subsequent transformation and uncontrolled
proliferation of these cells. It has been proposed that the CKIIalpha
subunit of T. parva induces mitogenic pathways of host leukocytes by
being exported into the host cell. The evidence for this is the
existence of a predicted N-terminal secretion signal-like peptide. We
tested this hypothesis by analyzing gene structure, translation, and
protein localization of the T. annulata CKIIalpha (TaCKIIalpha). The
determined TaCKIIalpha-ORF potentially codes for a 50 kDa protein with
an N-terminal extension including a possible signal sequence not
present in CKIIalpha proteins of non-Theileria species. However,
antisera raised against TaCKIIalpha recognized a protein of a molecular
weight of about 40 kDa and, therefore, inconsistent with this predicted
molecular weight. We demonstrate by in vitro transcription/translation
that this discrepancy is due to translation from a downstream
initiation site omitting the putative N-terminal signal sequence and
thus excluding the notion that the protein product is secreted via the
classical secretory pathway. In corroboration immunofluorescence
investigations suggest that the TaCKIIalpha subunit is confined to the
parasite schizonts within the host cell. On the basis of the above
findings it seems highly unlikely that export via the classical pathway
of the parasite CKIIalpha is the way in which this protein possibly
contributes to host cell transformation. Copyright 2003 Wiley-Liss, Inc.