Design a Western Blot for PAM

Band shift · Use the separately labelled calculated mass and catalog-observed evidence above. A sequence annotation does not establish an observed migration shift. Verify target identity with orthogonal controls.

Isoforms · UniProt lists six isoforms. Relative to the canonical sequence, isoform 2 lacks residues 388–494, isoform 3 lacks 829–896, isoform 4 lacks 829–914, and isoform 6 lacks 897–914; isoform 5 has a change at 896. Check whether the antibody epitope lies in an altered region before assigning bands to isoforms.

PTM · UniProt lists phosphoserine at 918, 929, 942, 946, and 957, plus phosphothreonine at 943. The 946 phosphorylation is attributed to UHMK1 in vitro; that does not establish it in the tested sample. These are UniProt coordinates, which may differ from antibody or paper numbering. Site annotations alone do not establish a visible shift.

Induction · No general induction response is established by this guide. A pathway or gene-set association is not evidence of induction in a particular specimen. Verify the relevant treatment and control in a target-specific experiment.

Transfer · Plan transfer around the approximately 120 kDa observed band and verify recovery with a molecular-weight marker. PAM is annotated as a single-pass secretory-vesicle membrane protein, so check both transfer and extraction when signal is weak. The supplied features do not identify a particular membrane, buffer, or transfer setting.

Blocking · Standard workflow guidance: follow the A00332-2 datasheet where specified. Otherwise compare 5% milk or 5% BSA in TBST; for a phospho-specific assay start with BSA. Optimize background and specific signal with matched controls.

Quantitation · Standard workflow guidance: quantify only a validated target band within the linear exposure range. Use consistent sample preparation and loading, retain biological replicates, and avoid interpreting saturation or loading differences as regulation.

Interpretation · The supplied observed band is approximately 120 kDa, while the predicted mass is 108.3 kDa. PAM has an N-linked glycosylation site at UniProt Asn762, a signal peptide at 1–20, and a propeptide at 21–30. These features merit consideration, but their presence alone does not establish the cause or size of the apparent mass difference.

PAM has a signal peptide at UniProt residues 1–20 and a propeptide at 21–30; its keywords also include cleavage on pairs of basic residues. Compare antibody epitope coverage and sample fractions before assigning a lower band to processing. The supplied features do not specify a cleavage product's size.

PAM is annotated at the secretory-vesicle membrane and in secretory granules, with a single-pass membrane segment. Include an appropriate membrane-containing fraction when comparing samples, and keep fraction preparation consistent for quantitation. A weak whole-lysate band alone does not establish low PAM abundance.

First compare each band's apparent size with the six annotated isoforms and the antibody epitope. PAM also has a signal peptide, propeptide, an N-linked site at UniProt Asn762, and cleavage-related annotation. These provide candidates to investigate, but do not identify any extra band without supporting evidence.