Table 1 MG Proteins in Cancer and Normal Tissues

HMGA1a (HMG-I, HMG-I/Y),

HMGA1b (HMG-Y),

HMGA1c (HMG-I/R)

6p21

Highly modified with numerous sites of phosphorylation, acetylation and/or methylation. Possibly SUMOylated and ADP-ribosylated.

Nucleus but has role in shuttling HIPK2 (homeodomain-interacting protein kinase 2) to the cytosol

Abundantly expressed in undifferentiated and proliferating embryonic cells but usually undetectable in adult tissue

Overexpressed in malignant epithelial tumors and leukemia

HMGA2 (HMGI-C, HMGIC)

12q14-15

Phosphorylated

Nucleus – the second AT-hook is necessary and sufficient for nuclear localization

See HMGA1's

Invasive front of carcinomas. A splice variant without the acidic tail is found in some benign tumors.

HMGB1 (HMG1, Amphoterin)

13q12

Acetylated, methylated, phosphorylated, and/or ADP-ribosylated when actively secreted. An acidic tail-deleted isoform has been purified from calf thymus

Often nuclear but translocates to the cytosol and is actively secreted and passively released

Abundantly expressed in all tissues except neurons. Highest levels in thymus, liver and pancreas.

See Table 2

HMGB2 (HMG2)

4q31

Phosphorylated on up to three residues

see HMGB1

Thymus and testes

Squamous cell carcinoma of the skin, ovarian cancer

HMGB3 (HMG-4, HMG-2a)

Xq28

Lymphoid organs. mRNA detected in embryos and mouse bone marrow

mRNA detected in small cell and non-small cell lung carcinomas (SCLC, NSCLC)

HMGN1 (HMG14)

21q22.3

Acetylated, highly phosphorylated,

nucleus

Weakly expressed in most tissues

HMGN2 (HMG17)

1p36.1-1p35

Acetylated

nucleus

Weakly expressed in most tissues, but strong in thymus, bone marrow, thyroid and pituitary gland

HMGN3 (TRIP-7)

6q14.1

nucleus

Abundantly expressed in kidney, skeletal muscle and heart. Low levels found in lung, liver and pancreas

HMGN4 (HMG17, L3 NHC)

6p21.3

Highly phosphorylated

nucleus

Weakly expressed in all tissues