Cytosolic targeting domains of gamma and delta calmodulin-dependent protein kinase II.
Ca(2+)/calmodulin-dependent protein kinase II (CaMK-II) isozyme variability is the result of alternative usage of variable domain sequences. Isozyme expression is cell type-specific to transduce the appropriate Ca(2+) signals. We have determined the subcellular targeting domain of delta(E) CaMK-II, an isozyme that induces neurite outgrowth, and of a structurally similar isozyme, gamma(C) CaMK-II, which does not induce neurite outgrowth. delta(E) CaMK-II co-localizes with filamentous actin in the perinuclear region and in cellular extensions. In contrast, gamma(C) CaMK-II is uniformly cytosolic. Constitutively active delta(E) CaMK-II induces F-actin-rich extensions, thereby supporting a functional role for its localization. C-terminal constructs, which lack central variable domain sequences, can oligomerize and localize like full-length delta(E) and gamma(C) CaMK-II. Central variable domains themselves are monomeric and have no targeting capability. The C-terminal 95 residues of delta CaMK-II also has no targeting capability but can efficiently oligomerize. These findings define a targeting domain for gamma and delta CaMK-IIs that is in between the central variable and association domains. This domain is responsible for the subcellular targeting differences between gamma and delta CaMK-IIs.
Caran
N
N
Department of Biology, Virginia Commonwealth University, Richmond Virginia 23284-2012, USA.
Johnson
L D
LD
Jenkins
K J
KJ
Tombes
R M
RM
D016475:3T3 Cells; D000199:Actins / Q000032:analysis; D000595:Amino Acid Sequence; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D003599:Cytoskeleton / Q000737:chemistry; D003600:Cytosol / Q000378:metabolism*; D019281:Dimerization; D007527:Isoenzymes / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data
D000199:Actins; D007527:Isoenzymes; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases