GO_REF:0000002

GO reference used by source annotation pipeline

GO_REF:0000033

GO reference used by source annotation pipeline

GO_REF:0000044

GO reference used by source annotation pipeline

GO_REF:0000117

GO reference used by source annotation pipeline

GO_REF:0000120

GO reference used by source annotation pipeline

PMID:3972849

Cardiolipin is the membrane receptor for mitochondrial creatine phosphokinase

Mitochondrial creatine kinase binds to membranes specifically through cardiolipin; it is bound by liposomes only when they contain cardiolipin, supporting the IDA cardiolipin binding annotation (GO:1901612) as a membrane-anchoring interaction.

"mt-CK was bound by liposomes but only if they contained cardiolipin."

PMID:8086475

Developmental expression of sarcomeric and ubiquitous mitochondrial creatine kinase is tissue-specific

sMtCK (Ckmt2) mRNA in heart is undetectable prenatally and dramatically upregulated postnatally; this developmental expression pattern is the basis for the IEP heart-development annotation, reflecting rising metabolic demand rather than a direct morphogenetic role.

"sMtCK mRNA in heart is undetectable prenatally but is dramatically upregulated by 28 d postnatally."
sMtCK (Ckmt2) mRNA in skeletal muscle is extremely low prenatally and markedly upregulated postnatally, the expression basis for the IEP skeletal-muscle-development annotation.

"sMtCK mRNA in skeletal muscle is also extremely low prenatally but is markedly upregulated at birth and doubles by 28 d postnatally."

file:rat/Ckmt2/Ckmt2-deep-research-falcon.md

Falcon (Edison Scientific) deep research report: rat Ckmt2 / mitochondrial creatine kinase S-type (UniProt P09605)

Ckmt2/sMtCK is a phosphotransferase that transfers the gamma-phosphoryl group of ATP to creatine, catalyzing the reversible creatine kinase reaction (EC 2.7.3.2), supporting GO:0004111 creatine kinase activity as the core molecular function.

"CKMT2 is a **phosphotransferase** transferring the γ-phosphoryl group of ATP to creatine."
The creatine kinase / phosphocreatine system buffers and transfers high-energy phosphoryl groups using the creatine/phosphocreatine pair, the biochemical basis for GO:0046314 phosphocreatine biosynthetic process.

"The creatine kinase system buffers and transfers high-energy phosphoryl groups using the creatine/phosphocreatine (Cr/PCr) pair to maintain cellular energy homeostasis"
Mitochondrial CK localizes to the mitochondrial intermembrane and cristae space as a peripherally membrane-associated octamer, consistent with the mitochondrion (GO:0005739) and mitochondrial inner membrane (GO:0005743) localization annotations.

"Mitochondrial CK is localized to the **mitochondrial intermembrane and cristae space** and assembles into **cuboidal homooctamers** that are peripherally membrane-associated."
mtCK forms proteolipid complexes via direct interaction with cardiolipin and with the outer-membrane VDAC channel, recruiting ANT into inner-outer membrane contact sites; this supports the IDA-based cardiolipin binding annotation (GO:1901612) as a real but non-catalytic, membrane-anchoring activity.

"A key mechanistic concept is that mtCK forms **proteolipid complexes** via direct interaction with **cardiolipin**"
In heart, CKMT2 converts mitochondrial ATP into phosphocreatine that diffuses to cytosolic ATPases (the CK/phosphocreatine shuttle), the physiological role underpinning phosphocreatine biosynthesis rather than direct developmental control.

"In heart, CKMT2 is positioned to convert mitochondrial ATP into PCr, which diffuses to ATPases"
CKMT2 is the muscle (sarcomeric) mitochondrial CK isoform co-expressed with cytosolic muscle CK, so its association with heart and skeletal muscle reflects tissue-specific expression context rather than a direct role in tissue development.

"It is the muscle mitochondrial CK isoform co-expressed with cytosolic muscle CK."