Abstract
L1 is an axonal cell adhesion molecule found primarily on projection exons of both the CNS and PNS. It is a phosphorylated membrane-spanning glycoprotein that can be immunoprecipitated from rat brain membranes in association with protein kinase activities. Western blot analysis demonstrates that casein kinase II (CKII), a ubiquitous serine/threonine kinase enriched in brain, is present in these immunoprecipitates. CKII preparations partially purified from PC12 cells are able to phosphorylate recombinant L1 cytoplasmic domain (L1CD), which consists of residues 1,144- 1,257. Using these as well as more highly purified kinase preparations, phosphorylation assays of small peptides derived from the L1CD were performed. CKII was able to phosphorylate a peptide encompassing amino acids (aa) 1,173-1,185, as well as a related peptide representing an alternatively spliced nonneuronal L1 isoform that lacks aa 1,1771,180. Both peptides were phosphorylated with similar kinetic profiles. Serine to alanine substitutions in these peptides indicate that the CKII phosphorylation site is at Ser1,181. This is consistent with experiments in which L1CD was phosphorylated by these kinase preparations, digested, and the radiolabeled fragments sequenced. Furthermore, when L1 immunoprecipitates were used to phosphorylate L1CD, one of the residues phosphorylated is the same residue phosphorylated by CKII. Finally, in vivo radiolabeling indicates that Ser1,181 is phosphorylated in newborn rat brain. These data show that CKII is associated with and able to phosphorylate L1. This phosphorylation may be important in regulating certain aspects of L1 function, such as adhesivity or signal transduction.
| Original language | English |
|---|---|
| Pages (from-to) | 779-786 |
| Number of pages | 8 |
| Journal | Journal of Neurochemistry |
| Volume | 66 |
| Issue number | 2 |
| State | Published - Feb 1 1996 |
| Externally published | Yes |
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Keywords
- Casein kinase II
- Cell adhesion molecule
- L1 function
- Phosphorylation
- Rat brain
- Serine/threonine kinase
ASJC Scopus subject areas
- Biochemistry
- Cellular and Molecular Neuroscience
Cite this
Casein kinase II phosphorylates the neural cell adhesion molecule L1. / Wong, Eric V.; Schaefer, Andrew W.; Landreth, Gary; Lemmon, Vance.
In: Journal of Neurochemistry, Vol. 66, No. 2, 01.02.1996, p. 779-786.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Casein kinase II phosphorylates the neural cell adhesion molecule L1
AU - Wong, Eric V.
AU - Schaefer, Andrew W.
AU - Landreth, Gary
AU - Lemmon, Vance
PY - 1996/2/1
Y1 - 1996/2/1
N2 - L1 is an axonal cell adhesion molecule found primarily on projection exons of both the CNS and PNS. It is a phosphorylated membrane-spanning glycoprotein that can be immunoprecipitated from rat brain membranes in association with protein kinase activities. Western blot analysis demonstrates that casein kinase II (CKII), a ubiquitous serine/threonine kinase enriched in brain, is present in these immunoprecipitates. CKII preparations partially purified from PC12 cells are able to phosphorylate recombinant L1 cytoplasmic domain (L1CD), which consists of residues 1,144- 1,257. Using these as well as more highly purified kinase preparations, phosphorylation assays of small peptides derived from the L1CD were performed. CKII was able to phosphorylate a peptide encompassing amino acids (aa) 1,173-1,185, as well as a related peptide representing an alternatively spliced nonneuronal L1 isoform that lacks aa 1,1771,180. Both peptides were phosphorylated with similar kinetic profiles. Serine to alanine substitutions in these peptides indicate that the CKII phosphorylation site is at Ser1,181. This is consistent with experiments in which L1CD was phosphorylated by these kinase preparations, digested, and the radiolabeled fragments sequenced. Furthermore, when L1 immunoprecipitates were used to phosphorylate L1CD, one of the residues phosphorylated is the same residue phosphorylated by CKII. Finally, in vivo radiolabeling indicates that Ser1,181 is phosphorylated in newborn rat brain. These data show that CKII is associated with and able to phosphorylate L1. This phosphorylation may be important in regulating certain aspects of L1 function, such as adhesivity or signal transduction.
AB - L1 is an axonal cell adhesion molecule found primarily on projection exons of both the CNS and PNS. It is a phosphorylated membrane-spanning glycoprotein that can be immunoprecipitated from rat brain membranes in association with protein kinase activities. Western blot analysis demonstrates that casein kinase II (CKII), a ubiquitous serine/threonine kinase enriched in brain, is present in these immunoprecipitates. CKII preparations partially purified from PC12 cells are able to phosphorylate recombinant L1 cytoplasmic domain (L1CD), which consists of residues 1,144- 1,257. Using these as well as more highly purified kinase preparations, phosphorylation assays of small peptides derived from the L1CD were performed. CKII was able to phosphorylate a peptide encompassing amino acids (aa) 1,173-1,185, as well as a related peptide representing an alternatively spliced nonneuronal L1 isoform that lacks aa 1,1771,180. Both peptides were phosphorylated with similar kinetic profiles. Serine to alanine substitutions in these peptides indicate that the CKII phosphorylation site is at Ser1,181. This is consistent with experiments in which L1CD was phosphorylated by these kinase preparations, digested, and the radiolabeled fragments sequenced. Furthermore, when L1 immunoprecipitates were used to phosphorylate L1CD, one of the residues phosphorylated is the same residue phosphorylated by CKII. Finally, in vivo radiolabeling indicates that Ser1,181 is phosphorylated in newborn rat brain. These data show that CKII is associated with and able to phosphorylate L1. This phosphorylation may be important in regulating certain aspects of L1 function, such as adhesivity or signal transduction.
KW - Casein kinase II
KW - Cell adhesion molecule
KW - L1 function
KW - Phosphorylation
KW - Rat brain
KW - Serine/threonine kinase
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UR - http://www.scopus.com/inward/citedby.url?scp=0030066569&partnerID=8YFLogxK
M3 - Article
C2 - 8592152
AN - SCOPUS:0030066569
VL - 66
SP - 779
EP - 786
JO - Journal of Neurochemistry
JF - Journal of Neurochemistry
SN - 0022-3042
IS - 2
ER -