Abstract
We previously identified testicular protein kinase 1 (TESK1), which phosphorylates cofilin and induces actin cytoskeletal reorganization. We now report identification and characterization of another member of a TESK family, testicular protein kinase 2 (TESK2), with 48% amino acid identity with TESK1. Like TESK1, TESK2 phosphorylated cofilin specifically at Ser-3 and induced formation of actin stress fibers and focal adhesions. Both TESK1 and TESK2 are highly expressed in the testis, but in contrast to TESK1, which is predominantly expressed in testicular germ cells, TESK2 is expressed predominantly in nongerminal Sertoli cells. Thus, TESK1 and TESK2 seem to play distinct roles in spermatogenesis. In HeLa cells, TESK1 was localized mainly in the cytoplasm, whereas TESK2 was localized mainly in the nucleus, which means that TESK1 and TESK2 likely have distinct cellular functions. Because the kinase-inactive mutant of TESK2 was localized in the cytoplasm, nuclear/cytoplasmic localization of TESK2 depends on its kinase activity. A TESK2 mutant lacking the C-terminal noncatalytic region had about a 10-fold higher kinase activity in vitro and, when expressed in HeLa cells, induced punctate actin aggregates in the cytoplasm and unusual condensation and fragmentation of nuclei, followed by apoptosis. Thus, we propose that the C-terminal region plays important roles in regulating the kinase activity and cellular functions of TESK2.
| Original language | English |
|---|---|
| Pages (from-to) | 31449-31458 |
| Number of pages | 10 |
| Journal | Journal of Biological Chemistry |
| Volume | 276 |
| Issue number | 33 |
| DOIs | |
| Publication status | Published - 2001 Aug 17 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Cofilin Phosphorylation and Actin Reorganization Activities of Testicular Protein Kinase 2 and Its Predominant Expression in Testicular Sertoli Cells. / Toshima, Jiro; Toshima, Junko Y.; Takeuchi, Kazuhide; Mori, Reiko; Mizuno, Kensaku.
In: Journal of Biological Chemistry, Vol. 276, No. 33, 17.08.2001, p. 31449-31458.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cofilin Phosphorylation and Actin Reorganization Activities of Testicular Protein Kinase 2 and Its Predominant Expression in Testicular Sertoli Cells
AU - Toshima, Jiro
AU - Toshima, Junko Y.
AU - Takeuchi, Kazuhide
AU - Mori, Reiko
AU - Mizuno, Kensaku
PY - 2001/8/17
Y1 - 2001/8/17
N2 - We previously identified testicular protein kinase 1 (TESK1), which phosphorylates cofilin and induces actin cytoskeletal reorganization. We now report identification and characterization of another member of a TESK family, testicular protein kinase 2 (TESK2), with 48% amino acid identity with TESK1. Like TESK1, TESK2 phosphorylated cofilin specifically at Ser-3 and induced formation of actin stress fibers and focal adhesions. Both TESK1 and TESK2 are highly expressed in the testis, but in contrast to TESK1, which is predominantly expressed in testicular germ cells, TESK2 is expressed predominantly in nongerminal Sertoli cells. Thus, TESK1 and TESK2 seem to play distinct roles in spermatogenesis. In HeLa cells, TESK1 was localized mainly in the cytoplasm, whereas TESK2 was localized mainly in the nucleus, which means that TESK1 and TESK2 likely have distinct cellular functions. Because the kinase-inactive mutant of TESK2 was localized in the cytoplasm, nuclear/cytoplasmic localization of TESK2 depends on its kinase activity. A TESK2 mutant lacking the C-terminal noncatalytic region had about a 10-fold higher kinase activity in vitro and, when expressed in HeLa cells, induced punctate actin aggregates in the cytoplasm and unusual condensation and fragmentation of nuclei, followed by apoptosis. Thus, we propose that the C-terminal region plays important roles in regulating the kinase activity and cellular functions of TESK2.
AB - We previously identified testicular protein kinase 1 (TESK1), which phosphorylates cofilin and induces actin cytoskeletal reorganization. We now report identification and characterization of another member of a TESK family, testicular protein kinase 2 (TESK2), with 48% amino acid identity with TESK1. Like TESK1, TESK2 phosphorylated cofilin specifically at Ser-3 and induced formation of actin stress fibers and focal adhesions. Both TESK1 and TESK2 are highly expressed in the testis, but in contrast to TESK1, which is predominantly expressed in testicular germ cells, TESK2 is expressed predominantly in nongerminal Sertoli cells. Thus, TESK1 and TESK2 seem to play distinct roles in spermatogenesis. In HeLa cells, TESK1 was localized mainly in the cytoplasm, whereas TESK2 was localized mainly in the nucleus, which means that TESK1 and TESK2 likely have distinct cellular functions. Because the kinase-inactive mutant of TESK2 was localized in the cytoplasm, nuclear/cytoplasmic localization of TESK2 depends on its kinase activity. A TESK2 mutant lacking the C-terminal noncatalytic region had about a 10-fold higher kinase activity in vitro and, when expressed in HeLa cells, induced punctate actin aggregates in the cytoplasm and unusual condensation and fragmentation of nuclei, followed by apoptosis. Thus, we propose that the C-terminal region plays important roles in regulating the kinase activity and cellular functions of TESK2.
UR - http://www.scopus.com/inward/record.url?scp=0035903099&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035903099&partnerID=8YFLogxK
U2 - 10.1074/jbc.M102988200
DO - 10.1074/jbc.M102988200
M3 - Article
VL - 276
SP - 31449
EP - 31458
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 33
ER -