Isoform 5 of Tropomyosin alpha-3 chain

Tropomyosin alpha-3 chain (TPM3) is a cytoskeletal protein that regulates actin filament dynamics and contractility in muscle and non-muscle cells (UniProt: P06753-5). This isoform 5 variant is a 248-amino-acid product derived from the TPM3 gene. Tropomyosins are fundamental components of the thin filament apparatus and modulate interactions between actin and myosin-binding proteins across diverse tissues.

TPM3 is expressed broadly, including in the nervous system where it contributes to neuronal cytoskeletal organization and synaptic function. No specific disease associations were annotated in the UniProt record for this isoform (UniProt: P06753-5).

In Alzheimer's Disease, TPM3 isoform 5 shows an ambiguous regulation profile across subcellular fractions from human post-mortem AD brain tissue compared to age-matched controls (Chaparral AD proteomics). The mean log2 fold-change was +0.0787 across three measured fractions, suggesting minimal overall change, though directional variation exists between cellular compartments in the TMT-labeled proteomics experiment.