What is the clinical evidence from this study?

Study design: Other. Population: Skeletal muscle fiber identity. Intervention: CaMKIIγ/δ deletion vs. Control. Primary outcome: Skeletal muscle fiber type proportions and proteomic profile.

What does this research mean for the field?

Endogenous CaMKIIγ and CaMKIIδ maintain adult skeletal muscle type II myofiber identity, and their deletion causes a shift toward a type I-like proteomic program without a corresponding oxidative shift. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

To determine whether endogenous CaMKIIγ and CaMKIIδ maintain type II myofiber identity and coordinate contractile and metabolic programs in adult skeletal muscle.

September 17, 2026AJP Cell PhysiologyOpen Access

CaMKIIγ/δ deletion in mice increases type I fibers and induces type I-like remodeling without oxidative shift.

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Population

Tamoxifen-inducible, skeletal muscle-specific Camk2g/Camk2d double-knockout adult mice

Comparison

Deletion of CaMKIIγ/δ vs Control mice

Design

Preclinical

Follow-up

1 and 3 months

Key result

CaMKIIγ/δ deletion in adult mice increased type I fibers and reduced total type II fibers, inducing a type I-like proteomic remodeling without an accompanying oxidative shift.

Authors

HIHikaru Iwase YIYuka Ichihashi RTRyoka Tsukahara

Discussion

Member takes

Overview

Hypothesis-generating for CaMKIIγ/δ in adult myofiber identity; human studies required before any clinical relevance.

Key Points

To determine whether endogenous CaMKIIγ and CaMKIIδ maintain type II myofiber identity and coordinate contractile and metabolic programs in adult skeletal muscle.
Generated tamoxifen-inducible, skeletal muscle-specific Camk2g and Camk2d double-knockout adult mice.
Analyzed soleus muscles at 1 and 3 months post-deletion using muscle fiber typing, immunofluorescence, and laser microdissection proteomics.
CaMKIIγ/δ deletion did not alter body weight or muscle mass but led to an increased proportion of type I fibers, a reduction in total type II fibers, and a progressive decline in type IIa fibers.
Proteomic analysis revealed that knockout type II fibers acquired type I-like protein features despite maintaining a type II myosin heavy chain profile.
Mitochondrial oxidative phosphorylation protein programs decreased across type I, type II, and hybrid fibers, demonstrating that myofiber identity remodeling diverged from oxidative metabolic shifts.

Structured PICO

Population

Adult mice with tamoxifen-inducible, skeletal muscle-specific Camk2g/Camk2d double-knockout analyzed 1 and 3 months after deletion.

Intervention

Deletion of CaMKIIγ/δ

Comparator

Control mice

Outcome

Myofiber identity (proportion of type I and type II fibers) and proteomic remodelingsurrogate

Endogenous CaMKIIγ/δ acts as a homeostatic regulator of adult type II skeletal myofiber identity, uncoupling fiber identity-associated proteomic features from mitochondrial oxidative programs.

Cite This Study

Iwase et al. (2026) studied Skeletal muscle fiber identity. CaMKIIγ/δ deletion vs. Control was evaluated on Skeletal muscle fiber type proportions and proteomic profile. CaMKIIγ/δ deletion in adult mice increased type I fibers and reduced total type II fibers, inducing a type I-like proteomic remodeling without an accompanying oxidative shift.

synapsesocial.com/papers/6aabb6b55f706d05830e540b https://doi.org/10.1152/ajpcell.00464.2026

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September 17, 2026AJP Cell PhysiologyOpen Access

CaMKIIγ/δ deletion in mice increases type I fibers and induces type I-like remodeling without oxidative shift.

View Full Paper

Ask AI

Bookmark

Population

Tamoxifen-inducible, skeletal muscle-specific Camk2g/Camk2d double-knockout adult mice

Comparison

Deletion of CaMKIIγ/δ vs Control mice

Design

Preclinical

Follow-up

1 and 3 months

Key result

CaMKIIγ/δ deletion in adult mice increased type I fibers and reduced total type II fibers, inducing a type I-like proteomic remodeling without an accompanying oxidative shift.

Authors

HIHikaru Iwase YIYuka Ichihashi RTRyoka Tsukahara

Discussion

Member takes

Overview

Hypothesis-generating for CaMKIIγ/δ in adult myofiber identity; human studies required before any clinical relevance.

Key Points

To determine whether endogenous CaMKIIγ and CaMKIIδ maintain type II myofiber identity and coordinate contractile and metabolic programs in adult skeletal muscle.
Generated tamoxifen-inducible, skeletal muscle-specific Camk2g and Camk2d double-knockout adult mice.
Analyzed soleus muscles at 1 and 3 months post-deletion using muscle fiber typing, immunofluorescence, and laser microdissection proteomics.
CaMKIIγ/δ deletion did not alter body weight or muscle mass but led to an increased proportion of type I fibers, a reduction in total type II fibers, and a progressive decline in type IIa fibers.
Proteomic analysis revealed that knockout type II fibers acquired type I-like protein features despite maintaining a type II myosin heavy chain profile.
Mitochondrial oxidative phosphorylation protein programs decreased across type I, type II, and hybrid fibers, demonstrating that myofiber identity remodeling diverged from oxidative metabolic shifts.

Structured PICO

Population

Adult mice with tamoxifen-inducible, skeletal muscle-specific Camk2g/Camk2d double-knockout analyzed 1 and 3 months after deletion.

Intervention

Deletion of CaMKIIγ/δ

Comparator

Control mice

Outcome

Myofiber identity (proportion of type I and type II fibers) and proteomic remodelingsurrogate

Endogenous CaMKIIγ/δ acts as a homeostatic regulator of adult type II skeletal myofiber identity, uncoupling fiber identity-associated proteomic features from mitochondrial oxidative programs.

Cite This Study

synapsesocial.com/papers/6aabb6b55f706d05830e540b https://doi.org/10.1152/ajpcell.00464.2026

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

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