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Two members of the unusually large family of protein phosphatase 2B (PP2B, calcineurin) in Paramecium have distinct roles in calcium dependent processes.
Author(s) -
Fraga Dean,
Sehring Ivonne,
Kissmehl Roland,
Reiss Martina,
Gaines Raymond,
Hinrichsen Robert
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.854.3
Subject(s) - subfamily , biology , paramecium , genetics , protein family , gene family , gene , protein subunit , calcineurin , genome , evolutionary biology , microbiology and biotechnology , medicine , surgery , transplantation
We have characterized the calcineurin (CaN) gene family including subunits CaN‐A and CaN‐B based on sequence information obtained from the Paramecium genome project. Paramecium tetraurelia has 7 subfamilies of the catalytic CaN‐A subunit and one subfamily of the regulatory CaN‐B subunit, each with two members of considerable identity on the amino acid level (≥55% between subfamilies, and ≥94% within CaN‐A subfamilies, and full identity in the CaN‐B subfamily). At 14 members, the size of the CaN‐A family is unprecedented. We hypothesized that the different CaN‐A subfamilies were not strictly redundant and fulfill different roles in the cell. This was tested by selecting two phylogenetically distinct members of this large family for posttranscriptional silencing by RNAi. The two targets resulted in differing effects in exocytosis, calcium dynamics, and backward swimming behavior that supported our hypothesis that the large, highly‐conserved CaN‐A family members are not strictly redundant and at least two members have evolved diverse but overlapping functions. The fact that CaN regulates similar processes in more complex organisms suggests that these functional roles were acquired early in the evolution of this protein family.