9M5Y: Ca2+/CaM-CASK-CaMK complex

the crystal structure of the Ca2+/CaM-CASK-CaMK complex. Determined by X-ray diffraction at 1.8 Å resolution. Released 12 Nov 2025.

Method: X-ray diffraction
Resolution: 1.8 Å
Organisms: Homo sapiens, Rattus norvegicus
Chains: 2
Atoms: 3,391
Mol. weight: 56.01 kDa
Ligands: ANP, CA, PO4
Released: 12 Nov 2025

Explore 9M5Y in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9M5Y contains 23 α-helices and 15 β-strands across 2 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 18 helices, 13 β-strands

Element	Residues	Length	Sheet
α-helix	8-11	4
β-strand	12-20	9	1
β-strand	24-31	8	1
β-strand	37-44	8	1
α-helix	45-49	5
α-helix	56-68	13
β-strand	74	1	2
β-strand	77-83	7	1
β-strand	86-92	7	1
β-strand	97-98	2	2
α-helix	99-108	10
α-helix	115-134	20
β-strand	137-138	2	3
α-helix	144-146	3
β-strand	147-149	3	2
α-helix	156-157	2
β-strand	158-160	3	2
β-strand	167-168	2	3
β-strand	174-175	2	4
α-helix	183-185	3
α-helix	188-191	4
β-strand	196-197	2	4
α-helix	199-214	16
α-helix	223-232	10
α-helix	239-242	4
α-helix	247-256	10
α-helix	265-266	2
α-helix	267-271	5
α-helix	274-277	4
α-helix	279-282	4
α-helix	289-311	23

Chain B: 5 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	84-93	10
β-strand	100-101	2	5
α-helix	103-112	10
α-helix	116-118	3
α-helix	119-129	11
β-strand	137-138	2	5
α-helix	139-146	8

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Peripheral plasma membrane protein CASK	A	protein	338	Homo sapiens	O14936 (AlphaFold model)
Calmodulin-1	B	protein	153	Rattus norvegicus	P0DP29 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9M5Y_1 Peripheral plasma membrane protein CASK (chains A)
GPGSEFMADDDVLFEDVYELCEVIGKGPFSVVRRCINRETGQQFAVKIVDVAKFTSSPGL
STEDLKREASICHMLKHPHIVELLETYSSDGMLYMVFEFMDGADLCFEIVKRADAGFVYS
EAVASHYMRQILEALRYCHDNNIIHRDVKPHCVLLASKENSAPVKLGGFGVAIQLGESGL
VAGGRVGTPHFMAPEVVKREPYGKPVDVWGCGVILFILLSGCLPFYGTKERLFEGIIKGK
YKMNPRQWSHISESAKDLVRRMLMLDPAERITVYEALNHPWLKERDRYAYKIHLPETVEQ
LRKFNARRKLKGAVLAAVSSHKFNSFYGDPPEELPDFS

Sequence of entity 2 (B), FASTA

>9M5Y_2 Calmodulin-1 (chains B)
GPGSMADQLTEEQIAEFKEAFSLFDKDGDGTITTKELGTVMRSLGQNPTEAELQDMINEV
DADGNGTIDFPEFLTMMARKMKDTDSEEEIREAFRVFDKDGNGYISAAELRHVMTNLGEK
LTDEEVDEMIREADIDGDGQVNYEEFVQMMTAK

Ligands and cofactors

ID	Name	Formula	Copies
ANP	Phosphoaminophosphonic acid-adenylate ester	C10 H17 N6 O12 P3	1
CA	Calcium ion	Ca	2
PO4	Phosphate ion	O4 P	1

Primary citation

Structural basis for the Ca 2+ /CaM-mediated regulation of CASK-CaMK. Li, W., Wang, Y., Feng, W. Int J Biol Macromol (2025) 332:148495-148495. DOI 10.1016/j.ijbiomac.2025.148495 · PubMed

Other PDB entries of the same protein (UniProt O14936 (AlphaFold model), which also has an AlphaFold model), best resolution first:

1KGD 1.31 Å, Crystal Structure of the Guanylate Kinase-like Domain of Human CASK
9M6G 1.7 Å, the crystal structure of the Ca2+/CaM-CASK-CaMK-Mint1-CID complex
9KYS 1.76 Å, the Ca2+/CaM-CASK-ARD complex
3C0I 1.85 Å, CASK CaM-Kinase Domain- 3'-AMP complex, P212121 form
6NH9 1.85 Å, Crystal structure of a human calcium/calmodulin dependent serine protein kinase (CASK)…
6NID 1.86 Å, Crystal structure of a human calcium/calmodulin dependent serine protein kinase (CASK)…
1KWA 1.93 Å, Human cask/lin-2 PDZ domain
7OAJ 1.93 Å, Crystal structure of pseudokinase CASK in complex with compound 7
3MFR 2.0 Å, CASK-4M CaM Kinase Domain, native
3MFS 2.1 Å, CASK-4M CaM Kinase Domain, AMPPNP
7OAL 2.17 Å, Crystal structure of pseudokinase CASK in complex with compound 25
3C0G 2.19 Å, CASK CaM-Kinase Domain- 3'-AMP complex, P1 form

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